Power Buffing Technique
Polishing metals with a rag wheel on a hand held machine, or on a lathe is called power buffing. It is an excellent way of getting very fast results. It is also an excellent way of getting a knot on the head, scalped, strangled or destroying your work piece. So do it right and protect yourself and others around you.
Firstly, ensure that you are using all the necessary protective equipment, that all objects that may be ensnared in the buff (necklaces, wristbands, long hair etc.) are secure, and out of the way, and that the item you are going to polish is also secure. Make sure that you have room to move around the workpiece, and do not work in any areas where if the buffer becomes snagged - it may force your hands into sharp objects, or where parts may break loose and hit you, or those around you.
Normally the first cut will involve a relatively stiff buff and coarse compounds.
MAKE SURE that your machine turns at the correct speed, a useful formula is
i.e.: 3500X8" = 28000, divided by 4 =7000
This is the feet per minute that your buffer edge is travelling . This, by the way is practically the optimum speed for most compounds. As a point of interest, if something does come off the buff at this speed it will be travelling at 81.6 miles per hour, so DUCK!
If your buff turns much faster than this you will be wearing the compound. I often buff much slower, depending on the surface I am finishing and its ease of accessibility, as a slower turning buff is much more controllable and it also generates a lot less heat.
The first thing is to clean the surface with our Greasy Joe grime and crud remover to ensure that the area is clean - you can't polish dirt.
Then load up the buff with compound. Make sure that when you do this you apply the bar to a section of the buff that is turning away from you. The Ideal method is to dampen the buff wheel around its edge and then dip the compound into hot water to soften it, and rub this into the buff, loading it up with abrasive and then stand it to dry. This will make the buff cut at its best and will not waste compound.
Do not apply varying grades of compound to one wheel, the finish that you will achieve will only be as good as the coarsest piece of grit on that wheel, and you will find scratches in your finished article.
OK, tThe buff is loaded and we will now take the buff to the item, or the item to the buff,
if you are using a pedestal. Again the important thing is to be aware of the rotation
and the forces in action. Make sure that if the item or buff kick in any way, that they are pushed away from you, and be aware that if the buff meets an edge, IT WILL SNAG IT!
If you push the item against the rotation of the buff this is called a cutting stroke, and it will normally leave a small trail of compound on the item where the buff has been.
To go with the rotation of the buff is called a coloring stroke. This will remove polish from the item and brightens up the finish. One cutting stroke and one polishing stroke equals one cut.
A lot of people tend to press hard on the buff, this is unnecessary and is a sure fire way to generate heat that will discolor or maybe even warp the piece. It is far better to use light pressure and allow the compound to do its work. This also makes the buff much more controllable and leaves less buff marks on the piece.
The first cut being completed we blend in any areas that we could not get at by hand.
Then clean off any surplus compound.
Progress to the next cut, using a different buff wheel.
The second cut will show up the scratches from the first cut best if it is at 90 ° to the first. This cut is continued until all the marks from the first cut are gone, and so we continue through the cuts and grades, going from one angle to the other until we reach our finishing cut.
This will achieve the best finish if it is done in the direction of the grain in the piece that we are polishing. On a cylinder, like a tank, or something of that nature, we finish in the direction it was rolled.
On a stamping it is not quite so easy to see the grain, but normally one direction of cut will yield a slightly better finish than another: that is the grain. Of course on a casting there is no grain as such because the metal is poured, but it can still be directional in its ability to yield finish.
Remember to NOT apply pressure to the buff. On the last cut this is the surest way to leave buff marks, and possibly over heat the item. If you find you still have buff marks, remove them by powdering your piece with sodium bicarbonate or talc and buff it again.