WELCOME to the anvilfire Guru's Den - V. 3.3

THIS is a forum for questions and answers about blacksmithing and general metalworking. Ask the Guru any reasonable question and he or one of his helpers will answer your question, find someone that can, OR research the question for you.

This is an archive of posts from August 8 - 15, 2011 on the Guru's Den
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Gravity and weapons : Somewhere I saw a statistic that said every time there is one of those gun shooting celebrations in the Middle East with dozens of idiots firing rifles and machine guns up into the air that one of more people are killed by the falling bullets. . . I wounder how many of these are blamed on the other side so they can start killing each other again?

During WWI when planes first went into combat they needed weapons FAST. SO they made little cast iron "bombs" that looked like a cartoon rocket with fins and a hard steel point. They only weighed about a pound and were dumped out of open cockpit airplanes by the box full. The reason I knew about them is because they were selling them as surplus when I was a kid. "Genuine WWI bombs" No explosive, just dead weight. I suspect the planes could not carry enough of them to be useful.
   - guru - Sunday, 08/07/11 22:54:27 EDT

Imagine what the fall out in WWII was when a thousand plane raid was over a big German city. The Germans had a dud rate of about 40% at the end of the war, and think of the thousands of AA shells fired and also all the rounds fired by the bombers and fighters. Anything that did not explode fell back to earth. The US had a 17% dud rate on aerial bombs, the Brits about 19%, so if a thousand US planes made a raid with 10 500#ers each that is 1700 unexploded bombs. And that is why in the 70's they were still digging house foundations by hand in Germany. I think finding a unexploded bomb or AA shell with a shovel would be better than with a backhoe.
   ptree - Monday, 08/08/11 07:12:29 EDT

I had one of those little "bombs" when I was a kid. The guy who sold it to me at the surplus shop told me that by the time the little munitions got to the ground they would have enough velocity to punch little holes in everything, roofs, helmets, cars, pretty much anything.

A year ago in Turkey, as it is customary to shoot guns in the air for events, at a wedding the groom held an AK with one hand and fired in the air. The recoil made the gun push frontal and out of control, the man ended up killing his father, mother and some of the brides family.
   - Nippulini - Monday, 08/08/11 10:33:10 EDT

The anvil was unusable as anything but a really heavy paperweight when I got it. The edges were chipped and the face looked like it had been used for sledge hammer training on cold steel. The build up rod I used for the mild steel parts was 7018 or equivalent. for the last half inch on the face I used MG710 a tool steel electrode that will produce a rockwell of about 55. The TIG rod I am going to use is also a tool steel rod. The reason I do not want to heat it up is because it is very difficult to be that close to that much heat and do precise work.
   Tim Mann - Monday, 08/08/11 12:24:53 EDT

Tim, It sounds like you are doing a good job. I would look at the recommendations for the rod first. But I would think modest preheat in the necessary areas would be more than sufficient. What you want to avoid is thermal shock. The difference between room temperature and a few hundred degrees Fahrenheit makes a big difference in this regard.

I understand the being near the heat. . and nowhere to rest ones hands.

The way the weather has been lately a good soak in the sun might do the job ;)
   - guru - Monday, 08/08/11 13:08:00 EDT

Steel crossbow : Mike, if you plan on making a crossbow one could do worse than starting with "The Book of the Crossbow" by Ralph Payne-Gallwey. He was essentially a English gentlemen with a lot of time, money and fascination with crossbows. If I recall he gives specifics on the bow design and temper. He details a lot of internal workings too as well as windlasses, cranequins, etc. Of course it is still buyer beware.
   Martin - Monday, 08/08/11 14:51:56 EDT

Crossbow : A few books are where I would start on such a project. There is a lot of good info on the web but you can't beat something with drawings, detail dimensions, all the caveats. . . One $25 book can save hundreds of dollars of expense, labor, heart break, injury. . . AND if you are cheap you can borrow it from the library or via ILL.
   - guru - Monday, 08/08/11 15:54:12 EDT

"The Crossbow" by Ralph Payne-Gallwey : http://www.crossbowbook.com/

Not sure if this is the same book. A lot of it is on-line
   - guru - Monday, 08/08/11 16:04:41 EDT

Yes that's it. Note that he has plans for a medieval bow and commends his springmaker to you for the prod. Of course there has been 2 world wars in that area Liege IIRC since he wrote it.

He was the curator of ancient weapons for the British Museum at one time.

Popular [Science?, Mechanics?] once had a write up on how to build a crossbow using leaf springs including some calculations on what the pull would be. I believe the article was published in the 1950's, I saw a copy in the 1970's or 1980's...

As the prod is truly the most dangerous part---Hold this stressed metal part up near your eyes and head and give it a sudden shock! And as most crossbow manufacturers sell replacement prods I would advise that one think of *buying* a commercially made prod.
   Thomas P - Monday, 08/08/11 16:12:31 EDT

Book : Martin, Guru
I bookmarked the web-site, looks like it might be a good book. I watched a program about the Roman Balista, they made a reproduction of it and it was a nasty weapon, there were two levers on the back with which they jacked the cable back, when the bolt was released it could go through several men at one time. The head of the bolt was tapered back on four sides, they found a skull with a square (hole) and made the assumption that a bolt from a balista had made it.
   Mike T. - Monday, 08/08/11 17:16:56 EDT

I suspect that if you do a little searching there is probably a couple more up to date books.
   - guru - Monday, 08/08/11 17:43:44 EDT

forging cast iron : I have been blacksmithing for 7yrs but I have only dealt with barstock & scrap parts off machinery, recently I decided to try using iron because I have plenty of cast iron laying around & steel is now getting expensive to expensive for a college boy, however I have trouble forging cast iron when I begin to hammer it, it seems as though it is sticking and holding when I place it back for a reheat it falls apart either in the fire or when I pick it up with my tongs. What am I missing here is cast iron unforgeable, I've become interested in this because of one of my history classes, I figured cast iron today is far superior than medieval iron. Has anyone tried this and what issues have they had and was anybody successful what was their trick. Like I have previously stated I've only had experience with bar stock, Iron is a different animal altogether
   Tye Bledsoe - Monday, 08/08/11 19:55:45 EDT

I have recently became interested in forging cast iron, one I became interested in because of a history class and two because bar stock is to expensive for a college student. I have only had experience with bar stock and parts off machinery, when I try to forge iron it falls apart even when it is beginning to stick together or so I think it falls apart after a reheat what am I missing I thought maybe its my coal I get my coal free because my dad is a coalminer some of it has sulfur you don't get the good stuff for free..lol
if there is any tips on what a problem maybe it would be appreciated and from what Ive read I believe I'm doing everything right obviously not lol.
   - Tye Bledsoe - Monday, 08/08/11 20:04:19 EDT

Tim : I would stay with the 400f preheat, but put a layer of kayowool, a thin firebrick, asbestos shingle or even a piece of wood between the hot surface and where I would rest My hand to reduce the "felt" heat.

I take it those tool steel rods air harden. When We used similar rod for die repair, We would temper at 400 after welding just to be safe, but the base material was A2 & D2.
   - Dave Boyer - Monday, 08/08/11 20:42:43 EDT

Cast Iron, Wrought Iron and Steel :
Tye, Cast Iron (CI) IS NOT forgeable. It is extremely high carbon and virtually inflexible. The only way to form it is to melt it and cast in molds OR to machine it making chips. There is also ductile iron which is a little flexible, can be welded by modern processes but not forged.

Wrought Iron is nearly pure iron with little or no carbon in a matrix of siliceous slag. Wrought is very ductile, generally forged at high temperature, is eminently forge weldable and cannot be hardened. This is the forgeable iron from the early Western iron age up until fairly recent times historically (about 100 years ago).

Steel is Iron plus a small amount of carbon (.01% to 1.2%) and some trace elements (silicon and manganese). All steel (even mild steel) is hardenable to varying degrees by heat treating. Mild steel has a wide forging range but is not as easy to forge weld as wrought which tends to be self fluxing.

The problem IS that in common language all three are simply called IRON as well as things made from them (guns = iron, all magnetic scrap = iron. . .). But there are large differences technically.

Buying bar stock is far more efficient than trying to forge ugly cast lumps even if they were forgeable.
   - guru - Monday, 08/08/11 20:59:24 EDT

Falling bullets : There are many reasons why a bullet, having been fired almost vertical, is highly unlikely to kill anybody on it's return to earth! One is that that same air which slowed it on the way up will also slow it just as much on the way down. The bullet will also have lost all spin so it will be tumbling rather than travelling point first. This will also slow it further as the side of a bullet isn't aerodynamic. I don't dispute that it would be unpleasant to be hit by such a falling bullet but the chances of being killed are tiny.
   - Philip in China - Monday, 08/08/11 21:17:09 EDT

Well. . . they ARE going a lot slower when they come down. 230 Feet per second (156 MPH) for an average proportion lead slug according to the NASA terminal velocity calculator. That is about 1/4 the velocity of the average large caliber bullet at 200 yards and close to the same at 400 yards. . .

In comparison, I've had gravel (a lower density than lead) thrown in front of me from the side of the road while traveling 55 MPH. Broke a headlight, put a hole through the radiator and cracked the windshield. At 3 times that speed . . ??
   - guru - Monday, 08/08/11 21:59:25 EDT

Falling bullets : Actually don't kill very many people. The NASA chart is pretty much correct and a projectile of say, .38" (9mm) diameter will be unlikely to penetrate much at only 200 fps. The old Daisy Red Ryder BB guns did almost that for velocity and a .177" BB has much less cross section than a .38 bullet. (Yes, a gigantic difference in mass, but that cross section is really what governs penetration, all other factors being more or less equal.) A .45 ACP Colt Model 1911 pistol has a muzzle velocity of around 970 fps and is noted for its "stopping power" because of two factors -- the relatively low velocity that means it doesn't over-penetrate and the high mass of the projectile - around 210 grains. Total effective force on target is on the order of 430+ ft/lb of energy. On the other hand, the falling .38 caliber projectile, with a mass of about 128 grains traveling at 230 fps will have a kinetic energy of only about 12 ft/lbs - roughly equal to a BB gun.
   Rich - Monday, 08/08/11 23:07:13 EDT

Ok, how many of you guys are willing to volunteer that test? You stand on the "X" and I'll fire as many rounds in the air as I can. Let me know when they land. :)
   - Nippulini - Tuesday, 08/09/11 08:37:41 EDT

Falling Bullets : SO maybe the reports of people being killed by falling bullets are a modern myth. Might be a good one for Mythbusters, they love things that go bang and using ballistic jell.

I do know our arrow shot straight up penetrated the hard ground several inches. . . . but then arrow mass is very high for their wind resistance.

Anyone ever shoot "flu-flus". Arrows with a single spiraled feather. Go like crazy for about 15 to 20 feet and stop dead. . .
   - guru - Tuesday, 08/09/11 08:45:05 EDT

American Wrought Anvil : Hello,

I have been on the hunt for an anvil for many years and recently lucked out. I found a small (100lb) anvil in very good condition. It has "American Wrought" with a horse shoe stamped in the side of the anvil. As said earlier, the anvil is in pristine condition but it does not sit flat on the floor or on a bench. The bottom has a hump in the middle. I was considering setting it up in my milling machine and milling it flat but I do not want to alter it if it will diminish the value of the anvil. My question is do I have a rare collectable anvil that should be left alone (maybe sell it and get something more usable)?

Thomas Mitchell
   Thomas Mitchell - Tuesday, 08/09/11 08:58:12 EDT

American Wrought Anvil : Thomas, a hump in the middle is often the sign of an unfinished casting. No matter what the brand of anvil someone may have used an original as a pattern and made a cheap cast iron copy. This is currently being done in Mexico and many show up in Southwestern flea markets. There should be square handling holes under horn, heel and centered in the bottom. Lack of these is an easy indication of a cast copy.

American wrought anvils were made by a former employee and competitor of Hay-Budden both in Brooklyn NY. All the logos recorded by Richard Postman were the word American in all caps forming a diamond shape (letters taller in the middle) with the weight under the name. No horseshoes in the logo but that is not and absolute. But you could be mistaking a part of the weight marking as a horseshoe.

These were a good quality wrought anvil with steel face and fairly rare.

Flattening the bottom should not hurt the value but bases of forged anvils are rarely parallel to the face. Without careful leveling an excessive amount of material may be removed. I would go after the high place with a grinder. Generally you want some relief in the middle to prevent rocking.

On the other hand, it would be a LOT easier and simpler to make a stand to fit. Either relieve the center or cut a hole in the middle of the stand. Cutting or carving wood is a lot easier than metal and does not reduce the weight of the anvil.
   - guru - Tuesday, 08/09/11 09:45:02 EDT

Stand Reliefs : On a steel stand a hole could also be cut OR a wooden pad with relief put between anvil and stand. Many commercial cast iron stands had a large oval hole where the anvil sits for this purpose.
   - guru - Tuesday, 08/09/11 09:57:24 EDT

Anvils are often caulked in place with silicon caulk to reduce noise. This would also stop rocking.
   - guru - Tuesday, 08/09/11 10:04:39 EDT

Flu-flus : I recall that when I was messing with archery as a kid we had some arrows with that spiral fletching - they were supposed to be for shooting birds on the wing and kept your misses from going into the next county. I wouldn't know, as I never missed. Right!

My brothers and I did the same damn dumb "shoot the arrow straight up" deal as you did Jock, but we had a different twist on it. We had a cardboard box with a bulls-eye painted on it and one guy would shoot the arrow and the other idiot would run around with the box to "catch" the arrow. The arrow thing was by no means our dumbest or most reckless adventure, either. I will never understand how we managed to survive growing up with all our digits and organs intact.
   Rich - Tuesday, 08/09/11 11:19:45 EDT

bullets falling : Mythbusters did a segment on that. Their conclusion was that it it is a myth.
   JimG - Tuesday, 08/09/11 11:36:29 EDT

How we got started :
Its funny the things that get you started on various interests. Our archery stint started when my dad was doing some wood working and my brother picked up a long slender piece of pine trimmed from a board and made a bow out of it. Then another one of us broke his make shift bow. . . So we got into bow making, the purchased various bows from the sporting goods store. Dad found a Herter's Catalog and we bought fletchings, knocks, tips, and various bits and pieces. . .

Our guitar making stint started when I found my son using up a supply of balsa wood to make a model guitar. . . I asked why not build the real thing? He responded I don't know how. I said I'll teach you and he gave me one of those "Oh right" looks. . . He didn't know I'd spent a couple years studying violin and guitar construction when I was in high school and wasn't completely clueless. We spent two years studying, working, making fixtures and two so-so guitars. But it was a lot of fun.

My interest in blacksmithing started when I was about 12 and I had the idea of making a gift of hand made jewelery for a girl and putting fancy marbled temper blue on them. That is when I started reading Machinery's Handbook and looking for blacksmithing references. There was nothing in the library at the time except Eric Sloanes American books (Museum of Early American Tools, Barns and Covered Bridges. . .).
   - guru - Tuesday, 08/09/11 11:46:15 EDT

Rich I can just so picture you doing that! (And then as an adult you got into a career where you ran around trying to avoid projectiles...).

Cast Iron vs Wrought Iron is sort of comparing apples to zebras. Also remember that a lot of modern industrial practice is not focused on making things *better* but in making them *cheaper*.

Since a goodly part of grey cast iron is graphite lenses you need to consider what happens to them as you heat and hit the metal. In wrought iron you can heat the silicates till they are plastic. Graphite doesn't do that so much and pretty much waits until it can go into solid solution in the iron.

And don't let's forget galvanized metal called "tin" as in "a cat on a hot tin roof."
   Thomas P - Tuesday, 08/09/11 13:30:34 EDT

Actually, mythbusters confirmed AND busted the shooting bullets in the air story at the same time- it turns out that if you fire the bullet absolutely perfectly straight up, it acts as Rich describes, losing its spin and becoming a slower falling dead weight.
Unfortunately, almost nobody does this- and any angle, however slight, tends to mean the bullet keeps acting as a bullet should, and penetrates when it hits.
So sometimes the bullets dont hurt, and sometimes they do.
The main thing in your favor in terms of survival is how big the world is, and how small, relatively speaking, you are- but if you get hit by a bullet that was shot more or less up, it can still kill you.
   - ries - Tuesday, 08/09/11 13:41:37 EDT

American Wrought Anvil : Not sure what is meant by "square handling holes under horn, heel and centered in the bottom. Lack of these is an easy indication of a cast copy." I will look tonight for any indication of something in these areas. I was thinking of welding up an angle iron stand for the anvil, with the center open so the bulge should not be a problem. As for the weight stamped on the side, is that typically done after the casting is finished? I purchased the anvil from an estate sale where I got a lot of other antique tools. The owner passed away at the age of 99. How long ago did the copies start showing up out of Mexico? I would like to think it is a real original but I have been fooled before. It has a nice ring and the rebound is great. Thanks for knowledge dump.

   Thomas Mitchell - Tuesday, 08/09/11 14:43:09 EDT

Falling bullets : I have a little experience with them. When I was a kid in the post-war Philippines, a wedding took place about a mile from our house. I felt a poke in the back, and awoke to the sound of falling glass. I put mu hand to the small of my back and found it was bloody. Mother bandaged me and in the morning we went 17 miles by bus to the hospital. The doc removed a .30 M1 carbine round that had penetrated about half an inch. I still have the bullet.
   John Odom - Tuesday, 08/09/11 15:50:24 EDT

bullit strike : something else to factor in. consider all things equal, then add wind speed and direction at 3000 ft. mean elevation, then the actual rotation of the earth, shoot straight up and stand there, not moving. it is probably the safest place. DO NOT TRY THIS AT HOME, i am only posting the beginning of the lesson affecting the path and speed of bullet travel. this comes from 6 years of professional shooting for Uncle Sam. end result is you may hurt or kill your neighbor or the person in the next camp.
   - keith - Tuesday, 08/09/11 15:52:36 EDT

If I were to die tomorrow there would be anvils I bought in 1983 and anvils I bought in 2010 in my estate. The age of the anvil would not correlate strongly with when I bought it either.

Handling holes are easy to find. They were used as places the large tongs used to manipulate traditionally made anvils would lock into. As cast anvils don't need to be held under steamhammers to shape them they are skipped.
   Thomas P - Tuesday, 08/09/11 16:12:14 EDT

American Wrought Anvil : If its a casting then its NOT an American Wrought, it is a cheap copy.

Wrought anvils have marking stamped IN and cast anvils generally have raised markings but not always. An Example is Kohlswa Swedish cast steel anvils, their name is cut shallowly into the pattern and almost looks stamped.

Most cast anvils with weights have them marked in the nearest 10 pounds and often just in tens (10 = 100 lbs +/-, 25 = 250 lbs +/-. . . )

If you haven't seen the handling holes then you probably have not looked at the bottom to see why it is rocking. Might be thick paint, tar, goo, something stuck in the handling hole (rock/gravel). .

Note that while cast steel anvils do not NEED handling holes many have been case with them in the sides for heat treating (See Hungarian Cast Steel Anvil

Cheap cast copies have been being made by foundries for a very long time, its just that the current crop are coming from South of the border. . Taking advantage of NAFTA. But if it has a nice ring and rebound its probably not cast iron.
   - guru - Tuesday, 08/09/11 16:36:18 EDT

Schools for Metallurgy : Hayden-I got my degree from Ohio State in 2001 and have been working in the open die forging industry since 2003. There aren't too many schools that still offer a true metallurgical engineering degree any more. Most have replaced that with materials science and you then specialize in metals if that is your interest. There are quite a few universities and colleges with this program. I'd check Consumer Reports or do web search as they are located all over the country and I am sure that I am not familiar with most of them. There are still quite a few forges shops in the US, though most are closed die shops, but they still need metallurgists. There are also opportunities for metallurgists at many of the large manufacturers (automotive, heavey equipment, mining, military etc) as well as in steel mills. I doubt you'd have trouble finding work if you are a hard working individual. One suggestion I can make is that you consider a dual degree in both metallurgy and welding engineering. There are only two schools that offer welding engineering and one is Ohio State. Heavy fabricators and good machinists seem to be in demand in the mid-west and northern parts of the US as well as in Canada and Texas since the demand for oil and other mineral and energy sources is spurring a great deal of activity in both mining and oil/gas exploration. If you have any interest in metalworking at all, these two degrees should allow you to combine your vocation and avocation as I have done.
   Patrick Nowak - Tuesday, 08/09/11 23:02:23 EDT

American Wrought Anvil : If the anvil is a truly wrought anvil, "American" above the horseshoe, and "Wrought" below is an "American horseshoe wrought anvil" Sold by Montgomery Wards. Originally made by Hay-Budden, later by Columbus Forge & iron Co., though I do not know if there were other makers.

Tonight if you need page numbers I will find them for you from "Anvils in America". I just bought a later American horseshoe brand at an auction this spring.

   Milton - Wednesday, 08/10/11 06:57:46 EDT

My American Wrought anvil has AMERICAN above the horseshoe, WROUGHT under, the weight in pounds marked under THAT. Inside the horseshoe it reads TRADEMARK. Serial number on right foot under horn. It has a pretty narrow waist and long face. The ring is incredible, due to this I hardly use it save for public demos (so the whole town can hear!)
   - Nippulini - Wednesday, 08/10/11 08:29:34 EDT

NM Tech just made it into a "Top Ten College List for Value"!

My wife got home from play practice last night and said the director wants me to do some more forge work for the production---cutting into my production time for the State Fair which cuts into my budget for Quad-State, grrr.
   Thomas P - Wednesday, 08/10/11 12:08:35 EDT

Thomas : So don't do it. Sometimes you just have to tell your spouse "no" - and then deal with the fallout. Yeah, I wouldn't have the nerve, either. (grin)
   Rich - Wednesday, 08/10/11 14:26:13 EDT

American Wrought Anvil : On page 290 in "Anvils in America" shows a Hay-Budden made for Montgomery Wards. The description of the anvil is under Hay-Budden section and also mentioned on 289.

Page 344 states:..."In the fall of 1925 Montgomery Ward had stopped buying anvils from the Columbus Forge and Iron Co. ..."

If you know what to look for the two different makers of American Horseshoe brand will not be confused. One of the differences is the number of handling holes.

Hope this helps.

   Milton - Wednesday, 08/10/11 18:55:43 EDT

American Wrought Anvils : It seems there are two of these made at different times.
   - guru - Wednesday, 08/10/11 23:07:51 EDT

Casting Brass Etc. : I was watching How It's Made last night. It showed how a jeweler casts gold into a ring. He made a ring out of wax, placed it in a container of casting plaster, hardened it, then placed the plaster cast in an oven and heated to it to 350 deg. until the wax melted, then placed the mold in a centrifugal machine, used blow torch to melt the gold and then spun the cast to force the gold into it. That looked easy to me, however, I know gold has a low melting point. The centrifigal machine looks very easy to build, and if I could get the jewelers casting plaster ( whatever it's called ) it looks like knife butts-guards etc. would be easy to mold. I was wondering about mokume gane, partially melt silver, copper etc., spin it into the mold, let harden and it looks to me like that would work. Just an idea.
   mike t. - Thursday, 08/11/11 05:16:17 EDT

Centrifugal Casting and Lost Wax :
Mike, The 350°F gets the wax out but generally plaster molds must be calcined at 1100 to 1200°F. Otherwise the chemically bound water separates from the plaster making steam and you get a bubble ridden ugly casting. I've lost a number of hand made wax originals by not calcining properly.

Photo by Jock Dempsey  Figure 13, Failed castings. Click for detail What Can Go Wrong:

At the 2002 Camp Fenby weekend I was listed under "experimental casting" and THAT it definitely was.

It was also a comedy of other errors. These are the result of not calcining properly.

Lost wax is a wonderful way to make one-off pieces with complex shapes but the down side is if you have a failed casting all your work that went into the wax is lost. In modern lost wax casting the waxes are often made in silicon rubber molds made from a more permanent master or an existing item. So a "lost" wax is not a big deal because it is not the original.

While centrifugal casting gives a denser slightly better casting there is little advantage unless you are making many parts. In this case the molds for the many parts are made on a "tree" and they are all poured at one time.

You cannot melt and recast Mokume' Gane'. It is a laminated product that if melted would become a uniform alloy. Mokume' Gane' is made by fusing (welding) at less than the melting point. Then the material is rolled or forged to shape. Often is is cut, bent and twisted then reformed to create patterns the same as laminated "Damascus" steel. In Japanese Mokume' Gane' means "Wood grain like".

You can use common plaster of Paris for lost wax but there are special mixes that work better for metal casting. You can also add sand, talc and corn starch to common molding plaster to increase its refractoriness, strength and porosity. . . But like many DIY formulae you are on your own. . .
   - guru - Thursday, 08/11/11 08:57:32 EDT

Laminated Metals without Laminates :
There is a process for making laminated steels that could probably be applied to none ferrous as well. Powder metallurgy is used. This is a relatively high tech method where layers are created with various metal powders and then they are hot pressed together. This welds the powder into a solid with the layers intact. The heavy billet with thick layers is then rolled out into one with thin layers. . .

I've probably muddled the terms above but you get the point.
   - guru - Thursday, 08/11/11 09:18:58 EDT

American Wrought Anvil : I have taken some pictures of the anvil. The square handling holes are now glaringly obvious. Wish I would have studied the anvil a little more before I started conversing with yall but oh well. Based on what Milton said it appears the anvil is an "American horseshoe wrought anvil" sold by Montgomery Wards. I would like to thank you all for your knowledge. Pictures of the anvil can be seen here: http://tinkerordie.com/2011/08/11/american-horseshoe-wrought-anvil/
   Thomas Mitchell - Thursday, 08/11/11 11:29:31 EDT

The term for casting mold material is "Investment" and there are different types for different temperatures/metals.

If you are interested in the subject (and live in the USA) many community colleges offer out of hours jewelrymaking classes that usually include a lost wax class as part of the series.

You may want to look into Precious Metal Clay, PMC, as well as an easier method of making things.

I generally use oil sand, (petrobond), for casting knife fittings as the turn around time is minimal. I've had a problem with a casting and remade the mold and re-cast it in under 15 minutes before! (I've also inadvertently transferred fingerprints with it before.)

   Thomas P - Thursday, 08/11/11 13:41:09 EDT

Rich; as my wife has OK'd me going to Quad-State I would not dare to do anything that may end up rescinding that OK!

I'll just have to go into production mode over the weekend to get caught up, ugg I hate production mode! OTOH we have a good chance of thunder storms which makes for a much cooler Smithy!

Going to start the "last?" project for the play tonight---if I have the stock on hand.

   Thomas P - Thursday, 08/11/11 13:46:43 EDT

Petroboand and PMC :
I had someone give me some of the early "clay" casting material and it is actually fine sand with a Petro bond type binder. I have some regular Petro bond sand that I got from my foundry supplier. Same red color just slightly coarser sand. I suspect they are the same binder.

As Thomas noted if you have a good reusable flask you can make oil bond molds very fast and unlike green sand they are pretty fool proof. The sand is reusable except some of the burned parts that should picked out and thrown away. Low temperature alloys such as aluminum and zinc do not burn the sand but brass and bronze do.
   - guru - Thursday, 08/11/11 14:03:37 EDT

Actually I tend to use cat food cans and chile cans for my flasks, indexed along the side seam and held together with a hose clamp.

I figured out that the more flasks you could pour at a time the easier things were.

I did have formal training in making petrobond molds through an out of hours casting class held at the local (at that time) University through their art department. Great class---we started making molds day 1; though sad to say after the two swordmakers took it at the same time the NEXT time it was offered there was a limit on how many ounces of brass you could use. Too late we already knew the drill and could do it on our own!

I used to use petrobond a lot for pouring silver till silver went so high; now I wished I had hogged all the ingots I got for US$1 a troy oz.

They "PMC clay" I was talking about burns out to be fine silver in whatever shape you formed it in. I think you are thinking of the "Delft Clay" casting stuff which I never had a chance to use as I got 100# of new petrobond in a school auction. Another 5 years and I will have to buy some more...
   Thomas P - Thursday, 08/11/11 19:17:54 EDT

Mike t,

Gold melts at over 1900 degrees Fahrenheit. There are a lot of metals with higher melting points, but not many that are routinely cast on a small scale.
   Mike BR - Thursday, 08/11/11 20:08:43 EDT

Delft clay - That's the stuff. Not really clay. Just a fine grade of Petro bond for jewelery and small fine work.

The melting point of brass is only a little higher than gold. It melts easy enough in a small propane fired melter. Aluminum is about half and zinc melts at 900 and pours best at 1,100°.

A lot of home foundry guys do nothing but aluminum due to the low temperature and ease of finding scrap. There is a LOT you can do with Al including machinery parts especially if you make parts relatively heavy.

In the late 19th and early 20th century casting used to be part of much decorative ironwork. Lead and zinc accents (balls, "turnings" and flowers) were cast around bars and at places where collars would be used. Occasionally these hid welds or rivets but were often the joining means themselves.
   - guru - Thursday, 08/11/11 23:10:14 EDT

Melting Point : Mike BR....the reason I thought that gold had a lower melting point is because the jeweler used a blow torch to melt the small amount of gold. Seemed like it only took him a minute. Guru, I also noticed when the jeweler put the wax ring in the casting material, he set it in a vaccum chamber to get all of the air out of it ( you could see the casting material bubble up ), I wonder if that could have anything to do with the bubbly look in your little casts above ?
   Mike T. - Friday, 08/12/11 08:21:08 EDT

Vacuum Degassing :
Mike, this helps degas the metal and get small amounts of dissolved gas out of the metal but would not help the problems with the castings I had above. Steam was actually blowing the metal out the sprue as I kept pouring more metal in. . . These molds had been force dried over a forge fire but were far from fully dried much less calcined. It was an amateur mistake. I show it here and in our iForge article on lost wax casting of an example of just how wrong casting can go.

I've gotten very good plaster mold castings but they need to be heated to over 1,000°F and the best results are gotten when the metal is poured into a hot mold.

Most folks that do very much investment casting have a special furnace for the calcining. Plenty hot but not too hot. Some dewax at a lower temperature and recycle the wax, others just burn off the wax. Collecting the bulk of the wax is a much cleaner process.

Melting small amounts of metal in a melting bowl with a torch is common jewelery making practice. It also works with brass in small amounts but works better over a forge fire or in a gas furnace.

When you get into casting there are all kinds of techniques you can apply. I've built multi-part five piece ceramic molds, cast resin handles with a low temperature melting core to run wires through, designed and machined permanent cast iron molds for zinc casting and made plaster molds from large plasticine clay sculptures. Every mold and casting process usually applies to some other field or material either directly or indirectly.
   - guru - Friday, 08/12/11 08:56:48 EDT

On the same topic, how would gold and silver be laminated? Is flux needed? I don't have the money, technology nor equipment for the powdered method described above.
   - Nippulini - Friday, 08/12/11 10:10:26 EDT

Lost wax casting : MikeT, In that How They Do it show they did several things that are not normal routine for casting in a rotary caster. Fist any prudent user has a cover over the machine. Did you note that the actual caster was in a deep tub? If the hot metal hits the bottom of a too thin or weak investment it will rupture the bottom and the hot metal comes on out and splatters the tub. Not good if there is no cover. You normal heat the metal insert the HOT flask, heat the metal a little more, and in one fluid dance remove the touch, grasp the arm to let the retaining pin drop and as you let the arm go you drop the hinged cover.

Second the burn out and calcining of the investment was reported to have been 1300F about right from my memory.

The vacuum degas of the investment was too hard, but done to display, If done as vigorously as shown the water would have started to boil. In vacuum degassing the negative pressure is held to just get the bubbles out. Some folks hand paint the wax model with a very thin slurry of investment let that part dry and then invest.

Most of my experience is with Vacuum casting. The hot flask is set on a high temp rubber seal and the vacuum applied from beneath the flask as hot metal is poured. The investment is slightly pourous and the gasses in the mold hollow are pulled out. With good investment and good practice I never ever got the rough finish on the ring shown in the show. Mt castings were ready for light sanding and then on to polish. The exceptions were when i handled wax that was warm and left my fingerprints in the wax, and those faithfully appeared in the casting.

The biggest casting I did as a jeweler was probably 2 ounces. Mostly sterling silver, some coin silver and a little gold.

The burnouts to remove the wax were a step change in temp, ie take the kiln to say 350F for an hour to get the gross water out and start the wax burn then ramp up to say 1300F and then ramp back down to about 900F for the pour. I was using Kerr investment.
Also in the show they held the flask in water after the pour and then tilted the casting out into his hand. Saw a guy get a third degree burn that way. The investment had shattered as expected from thermal shock, but the casting was big, and still very hot. I used a metal bucket, dropped the flask and backed up as sometimes the flask would act as a percolator and shot boiling water. Once the rumbling sound stopped I would fish around for the flask and casting with tongs.
   ptree - Friday, 08/12/11 10:19:27 EDT

Nip,gold to silver can be done with solder. There are sever very nice fluxes but being cheap and having been taught by a German Master in the 70's I use borax dissolved in water, and Sparex in water to clean after.
   ptree - Friday, 08/12/11 10:21:20 EDT

Gold Silver Mokume' Gane' : Nip, the layers of clean metal are just stacked up, clamped between two steel plates, heated to the fusing temperature of the lower melting point alloy and then given a whack with a hammer while still clamped to help finish the weld. No flux is used.

Mokume' Gane' laminations are made with copper/silver, gold/silver, copper/brass. . Any two metals that show color differences. Some are enhanced by etching other not. Once the initial billet is made then patterns can be created the same as with laminated steel Damascus.

   - guru - Friday, 08/12/11 10:49:34 EDT

Don't forget steam casting and the poorman's centrifugal where you swing the mold in a sling around you *manually*.

For an interesting set of instructions for lost Wax Casting Theophilus gives details in "Divers Arts" on how they did it in 1120 AD. Both for large things like bells and small things like censors.

I have always considered casting to be inherently more dangerous than blacksmithing because while the temps may be hotter smithing; stuff stays where you put it or drop it! Casting mistakes can jump up and chase you screaming down the hall!
   Thomas P - Friday, 08/12/11 13:28:26 EDT

In casting if you drop the metal it goes everywhere FAST in many bits. In blacksmithing the (usually one) piece is all you have to be concerned about AND it can be picked back up and worked or put back in the forge. . .
   - guru - Friday, 08/12/11 15:03:11 EDT

I blame my opinions on the dangers of molten metal on Johnny Tremain!
   Thomas P - Friday, 08/12/11 17:08:59 EDT

I blame my opinions on spin casting on a friend who had a blow out on a spin caster with no lid. He had a number of spot burn scars.
   ptree - Friday, 08/12/11 18:39:48 EDT

Mike T,

I used to think gold must have a low melting point because it is so soft. Then one day I looked it up . . .
   Mike BR - Friday, 08/12/11 21:02:57 EDT

Mike T : Oxy Acetylene burns about 5700f, if that is what he was using. That is the hottest of the usual oxy fuel torch combinations.
   - Dave Boyer - Friday, 08/12/11 21:56:39 EDT

Joanny Tremain : I've read that book, Dove gave Johnny the cracke dcrucible to pour silver, the crucible nroke, pouring molten silver on his hand
   Hayden - Friday, 08/12/11 23:05:07 EDT

Johnny Tremain :
As a way of getting back at Johnny, Dove hands him a cracked crucible. When Johnny pours the silver for casting, the crucible cracks and the silver leaks onto the furnace. Johnny loses his footing and his right hand falls into the melted silver.
   - guru - Saturday, 08/13/11 00:03:32 EDT

Johnny Tremain : Holy Crap, what a memory!! After seeing that show with Paul Revere on Disney on a Summer Sunday night (1956 ?), a few day's later I burned several fingers reaching into what I thought was a cold ash pit looking for a piece of charcoal to write on the sidewalk. Mom swabbed my hand with vasoline then proceeded to wrap the entire group of burned fingers together. The pain wasn't that bad but I started to cry and wail uncontrollably. My mom asked if it hurt and between sniffles I said no, "but I don't want to have my finger's cut apart when they heal!!!!. I'll never forget on the show, Paul Revere telling Johnny, as he cut his fingers apart, "The Revolution need's whole men!!" By the way, I did all my casting using Oxy/Propane, plenty hot and a cleaner fuel than Acet, and blowout's are pretty much non-existant if you pay attention to leaving at least 3/4 of an inch of investment over the top of the wax. If you are in doubt but must cast anyway, a damp piece of non combustable fiberboard(I used to get pieces of asbestos, probably not available any more), placed behind the flask will prevent blowout's and not cool the plaster down at all. The other trick is to make a collar of stiff paper along the top of the flask, held in place with a rubberband, if it's too short for the wax. Pour up to an extra inch of investment and thing's will be fine.
   Thumper - Saturday, 08/13/11 01:23:00 EDT

Casting & Johnny : I tell my friends: "Blacksmithing can injure, but casting can maim." using the old dichotomy between hand tools and power tools.

We must have all read Johnny Tremain as kids, and the moment the casting incident was mentioned I remembered the finale of the book where the fingers were to be cut and freed. That really got your attention in 6th Grade!

So, Thumper, did your mother wrap the fingers separately, or do you have to wear a mitten on that hand when you go out in the winter? ;-)

A lovely morning on the banks of the lower Potomac; but lots of thunderstorms on the way for the weekend. Longship voyage had to be canceled for Sunday. :-( (But it's good for the crops! :-)

Visit your National Parks; New River Gorge is pretty cool: www.nps.gov/neri/

Go viking: www.longshipco.org
   Bruce Blackistone (Atli) - Saturday, 08/13/11 08:59:04 EDT

Buried explosives : Catching up on my forum reading. We were digging a trench in Vietnam and about 4' down found a French mortar round from the last "conflict". I would have been really pissed if that thing had gone off! An intersting place to say the least!
   S K Smith - Saturday, 08/13/11 09:32:35 EDT

Johnnt Tremain : Bruce to tell you the truth, I can't remember....however, since mom's are always right, whatever she did, didn't require surgery when it was all over....whew !
   Thumper - Saturday, 08/13/11 20:58:32 EDT

Heating to Release Stuck Stuff : I've been working on rebuilding an antique gun and have had great success using 1/2 & 1/2 tranny fluid and acetone as a rust release. After almost 2 weeks of soaking and testing, I've come to some part's that need heat to get them loose. I've done it on nut's and bolts, but never a revolver cylinder, I need to get the stuck nipples out (the cap and ball firing aparatus' which hold the ignition cap's in place and are screwed into the cylinder). Should I; A) Torch each chamber individually, or B) Soak the cylinder in the forge till just barely red and do all 6 at once? I'm worried about potential cracking on 150 yr old metal. There's one other 2 piece part that will take heat also but because of it's size, I'll use the torch method. By the way, The pistol is a "Savage Navy", by the Savage North Company, Google it up if you want to see a real unique Civil War handgun.
   Thumper - Saturday, 08/13/11 21:10:16 EDT

If you are replacing all the nipples I would drill them out and then use easy-outs to remove the remaining shell which generally loosens after the center is drilled out. Often there is nothing left except a coil of threads to remove. Then clean up with a tap. Use never-seize on the replacements so the powder corrosives do not get in the threads again.
   - guru - Saturday, 08/13/11 23:31:59 EDT

Johnny Tremain :
I vaguely remember the Disney movies running a number of times when I was a kid but few details. Never read the story. Tried to read part of it on-line but it was a much condensed version (plot outline) and not very interesting.

While the plot with many major figures of the revolution seems far fetched I had a great great grandfather that ran an Inn in Dumfires, Virginia before the Revolution and was a Ranking member of the Militia. It was at the cross roads traveled by Washington, Madison, Jefferson and others and surely a place where politics and revolution were discussed in secret.
   - guru - Saturday, 08/13/11 23:41:52 EDT

Stuck Stuff : Guru, That sounds a lot less dangerous, I had to do that to a few of the screws before they would soak loose enough to be removed. I always oil the nipples before replacing, been doing BP for 18+ yrs and never had a problem. Going against conventional wisdom, I use Hoppes Gun oil.
   Thumper - Sunday, 08/14/11 12:46:54 EDT

On a part that sits squarely on the table and the items to be drilled out have natural pilot holes its a no-brainer. Other times there may be more to consider.

On the nuclear jobs we did the most difficult job was getting the big 30 pound impeller nuts off the pumps. They all had a small hex and a large flange. The biggest impact wrenches and heat failed to get these loose most of the time. It was determined that reducing these big expensive custom nuclear parts to chips was the most efficient, least damaging and most cost effective method of removal by far. After we made a machine to do this it became the standard method of removal. Machine enough material off the nut and they just backed off.
   - guru - Sunday, 08/14/11 14:32:24 EDT

The nipples are on an arc flaring out from square with the cylinder, but as you said, with pilot holes it really is a no brainer. Interesting about those large nut's, you'd think removal after normal wear would have been engineered into the design with set screws or the like.
   Thumper - Sunday, 08/14/11 18:32:47 EDT

I've never had to replace my nipples. One tore in '05, but I'm much better now.
   - Nippulini - Sunday, 08/14/11 20:15:54 EDT

10,000 HP Pump Nuts :
First you have to read the reports from back in the late 60's about materials for nuclear power plants. It sounds like the introduction to an old Star Trek "Unknown conditions never before seen by man. . ."

Then there is the fact that many of these things were just conventional designs scaled up (Super Nuclear Size Me). AND they were expected to last a very long time. . . 10 years to first major inspection and maintenance and a 30 year life (now being stretched to 50 or more).

They also expected to maintain a nuclear power plant with a small crew of dozens. . . now thousands. . .

So with no experience in the actual conditions and the results these huge machines were built, and tweeked and modified to work.

These large nuts with 5" diameter threads and 12" and larger flanges were only installed at 250 foot pounds of torque and the same was expected to remove them. But the problem is that the pump propellers are trying to pull them selves off the shaft and they heat up faster than the shaft. Thus their shrink fit slips down toward the nut and over time the force makes the nut tighter and tighter until there was no way to hold the shaft from rotating it without damaging it when removing the nut. AND they don't make an impact wrench big enough. Torque multipliers couldn't do it. . .

Part of the problem is the large flange on the cone shaped nut results in a very large diameter friction surface that multiplies the problem.

Machining it off consisted of reducing the thickness outside the threads to about 1/2" and the flange to about 1/4" thick. The thin flange flexes a little and the nut loosens. . . Then it is easily removed without damaging the rest of the pump.

   - guru - Sunday, 08/14/11 21:27:00 EDT

Gold : Mike BR
My mother had a gold wedding band that she kept in a small box with cotton padding. The first time I took it out of the box to look at it, I noticed it would bend with hardly any pressure. I believe it was pure gold. It does surprise me that the melting point is so high.
   Mike T. - Monday, 08/15/11 05:08:55 EDT

Mike, Cerromet (now Bolton Metal Products) made a series of bismuth alloys that melt at temperatures as low as 117°F. They also make alloys that expand when they solidify. These are heavy dense alloys that look like lead. We used one that melted at around 250°F to create a fancy hollow core in a cast epoxy handle which was then heated in an oven to remove the core material. The core was for wires and a series of very small push button switches.

The fact that pure gold and copper are so soft they are what launched early man into working metals. It is found in its native state and can be worked with stone and wood tools. In fact, gold leaf was made by putting a thin piece of gold between two pieces of sheep skin and beating it with a wood or stone mallet.

Alloy gold has copper, silver, zinc or other metals added to it to make it harder and more durable. These also change the color of the gold (thus "white" gold) so the alloys vary. 14k (14 parts to 10 part alloy) is about 58% gold.

Using different colors of 14 karat gold it is possible to make striped or variegated 14k gold Mokume' Gane'. However, it is more common to use silver and copper alloys for this purpose.

Years ago Paw-Paw had some kind of project where he wanted to replace a plated zinc medalian with gold. He had some old gold jewelery to melt down for the project. I was not sure it was all gold and he insisted it was. . . It turned out the wings on some little butterflies were brass. The result was red gold and VERY hard. We put the small globular piece on the anvil and struck it with a 4 pound hammer and didn't hardly mark it. . .

The world of alloys is infinite and the research is all trial and error. While all the binary alloys have been created and tested in a global project there are many alloys with three or more metals each in infinite variations. There is still much to do in metals research. As in all research however funding is the problem.
   - guru - Monday, 08/15/11 08:27:22 EDT

Mike T, In Europe 18 Kt gold was the standard for wedding rings and at 18Kt the gold is very soft, and will self mold to the finger very quickly. One reason high school rings and the like are 10Kt at most is the 10Kt is hard enough to retain the fine detail in the design.
   ptree - Monday, 08/15/11 10:23:02 EDT

I don't think the correlation between hardness at room temperature and melting point is very strong. We all know that high carbon steels have a lower melting point than low carbon steels for instance.

Ptree all the HS rings when I was in school were at best sterling silver and at worst some odd alloy they were pushing as gold was too high
   Thomas P - Monday, 08/15/11 15:14:50 EDT

Hardness vs. Melting Point (Tungsten, Wolfram, Tungsteno, Volfram, Wolframio, Tungstène) : Tungsten is a good example. It has one of the highest melting points of any metal (5018°F - 2770°C) but is softer than hard tool steel.

While it is not as hard as tool steels for cutting it retains it hardness well into a red heat. This makes it excellent for some types of hot punches.
   - guru - Monday, 08/15/11 16:33:11 EDT

NOTE: Many articles confuse Tungsten with Tungsten Carbide while is MUCH harder. Its another reason not to abbreviate with writing or speaking.
   - guru - Monday, 08/15/11 16:43:27 EDT

ThomasP, when I bought my HS ring in 1973 the price had doubled from the year before to about $79, which to a 16 to 20 hour a week min wager was a bundle. They did not offer any other choices that year, but the year following they had the fake gold alloy.

In Germany when I was apprenticing, that Sterling Silver was about $6 to 7 an Oz, and so when I came how I had plenty, close to a kilo. I used it in trying to start a jewelery biz while in college and had maybe 3/4 kilo when the hunt bros tried to corner the market and silver jumped to $40 an Oz. I thought of selling but then I thought where would I get more to make stuff. I did not sell and reap the profits and then silver came down and I used up most of the remainder. Unless it drops again I will not be making many jewels.
   ptree - Monday, 08/15/11 18:56:35 EDT

Yeah. I'm not even 100% sure there's a correlation at all between melting point and hardness at room temperature. But there was once a time when I *thought* there was. Then I read a novel about smuggling gold by casting it into a boat keel. I figured the book was wrong when it described how hard it was to get the necessary temperature -- until I looked it up.
   Mike BR - Monday, 08/15/11 19:17:52 EDT

Yup I once ran into a real deal on silver---an emergency sale where I had money on hand on a Sunday and picked up quite a lot. I ended up selling most of it to a close friend who's a silversmith for what I had in it. If I had just kept it to now I'd be in a *much* nicer truck. OTOH I helped out a good friend and didn't lose anything from it.

   Thomas P - Monday, 08/15/11 19:51:38 EDT

Deals :
Back in the 70's HUD paid to have several blocks of old buildings in downtown Lynchburg VA including a number of businesses leveled to be replaced with low income housing. The demolition contractor pushed all the structural steel up in a big pile. Apparently it was not part of their contract to dispose of the steel and at the time it cost more to move scrap than it was worth. . . There was several tons of heavy angle lintel from brick buildings, over 100 feet of I beam from 12" to 20". . all in a big tangled pile.

The steel sat there for a long time and I finally asked a friend that had property in the area what was up with it. Turns out it was given away twice and didn't get moved. . . The next weekend we moved it ALL. I had to give about half of it to a friend who helped us load. We each took about 4 loads.

I am still using pieces of that steel. But like Thomas had to do a few years ago I've been moving. . . Its hard to move a good collection of scrap. . .
   - guru - Tuesday, 08/16/11 08:18:10 EDT

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