Most Common Buffing and Polishing Errors
This cannot be stressed enough.
When trying to achieve a fine or polished surface finish you work in stages.
Do not move on to the next stage until you are completely finished with the current stage.
If you skip steps or do not completely finish each then you either pay for it with extra labor or end up with a poor job.
Machinery can speed up the process but replaces steps in the processes at the cost of efficiency and wear and tear on the equipment.
Common Finishing Stages:
- Chiseling / Forging / Casting / Machining
- Roughing with rasp or heavy grinder - fine machining
- Removing rasp marks with bastard file OR fine powered grinder (belt grinder)
- Sanding out file marks with 80 to 180 grit cloth abrasive
- Removing heavy sanding marks with 240 to 320 grit wet-or-dry
- Finishing with 400 to 600 grit (may be skipped depending on the materials or power buffing)
- Buffing with Tripoli, Emery or White - OR polishing with rubbing compound
- Buffing with Rouge (on soft metals)
- Polish the Wax
Each worker has slightly different steps.
When trying to create very flat crisp surfaces a hard flat surface and fine abrasive paper is used or a hard disk grinder with fine abrasive.
Some craftsmen use small handled tools with flat surfaces and fine abrasive paper attached.
When making smooth curved surfaces abrasive cloth strips are used and pulled across the surface.
Belt grinders have areas without a platen to conform to curves and curved platens are made for specific shapes as well.
Smooth curves starts with the eye and changes to feel by hand and then blending with a soft surface or cloth.
Importance of Steps
No matter what the steps each one should end with a uniform surface without showing any of the previous marks.
You MAY have smoother areas but never rougher texture than the current finishing method provides.
If a step is skipped or incomplete the next will create a smoother but uneven surface.
When polished the tool marks from the skipped steps will still show.
They will be shiny rough areas.
I am sure you have seen this on cheap polished goods.
These often go striaght from rough shaping to finish polishing.
Stiff buffing wheels can be used to "cut" running at high speed bringing down an uneven surface to a flat even one but it is an art that takes pressure and creates a lot of heat.
The heat and pressure makes the work stressfull and difficult to handle.
Using cutting to smooth, the results have rounded edges and muddled features.
For crisp edges the work must be done in careful stages rather than using a buff.
When a finishing system relies on cutting, especially in production, the results will not be consistent or top quality.
Coloring is the final finishing when a brilliant finish is the goal.
This is done with a soft cloth or buffing wheel and broken down or fine compound.
A very light amount of broken down Tripoli or rouge is used with a light touch.
When hand polishing the rag used to remove the last worn compound is used with a light touch for coloring.
As mentioned above, when crisp lines and beveled edges are wanted they are finished by hand.
Final polishing can be done with power tools.
However, using the steps in the list above and polishing compound such as
DuPont Orange Automotive Rubbing Compound a perfect finish can be achieved by hand.
When hand finishing it is even more important to carefully complete each step and to use fine paper (at least 320 or 400 grit) for the final sanding before polishing.
Done with care, a hand finish can be just as smooth and bright as a machine assisted finish.
It just takes care and persistence.