METAL POLISHING TERMS
by Lorne Goldman November 2009

M21
SMOOTH SPECULAR – initial cutting using aluminum oxide compounds.Beginning coarse and finishing with 320 grit, followed by buffing with aluminum oxide buffing compounds.
M22
SPECULAR – cutting with compounds the same an M21finish, followed by a final light buff.
M31
FINE SATIN – wheel or belt polishing with aluminum oxide or silicon carbide abrasives of 180 – 240 grit. 
M32 MEDIUM SATIN – same operation as M31, except 120 –180 grit is used.
M33  COARSE SATIN – same operation as M31, except 80 –120 grit is used.
#3
FINISH – a polish obtained by finishing with approx. 100 grit abrasive.More commonly used as a precursor to the final finish. 
#4
FINISH – general purpose, bright, clean finish, 150 –240 mesh abrasive used following prior grinding with coarser grit abrasives. 
#4 NON-DIRECTIONAL SATIN – 80 – 150 grit with no grain direction.
#4 LONG GRAIN – not the rice but a long continuous grain.
#6
FINISH – a soft satin finish, with lower reflectivity than the #4 finish.Use a medium abrasive oil 
#6
FINISH MIRROR BRIGHT – a highly finished product by buffing a surface which has been finely ground but still has grit lines heavier than a #7 finish.
#7
FINISH – a highly reflective finish produced by buffing a surface that has been finely ground, the grit lines are not removed during the final buffing process.
#8
FINISH – standard polished finish. It is quite reflective and is achieved by polishing with successively finer abrasives, then buffing with a fine compound.The surface is basically free of grit lines, although not completely invisible.
Finishing Compounds

Green Rouge

Primarily used in final finish buff operations on stainless steel, steel, brass, aluminum, nickel, and chrome. The green rouge is a chrome oxide, and is considered the best all around luster compound.

White Rouge

The white rouge is the softer than green rouge. Primarily used in the final finish of steel, stainless steel, and zinc. This compound is also a favorite in coloring aluminum and brass.

Red Rouge

Primarily used in the final finish of gold and silver, it is the finest of all rouges. It also produces an excellent finish on brass. 


 Stains & Rust with Stainless Steel Welds
by Lorne Goldman November 2009

stainless steel welding I have often received inquiries on why Morgan stainless steel (ss) welds discolor and can even rust at the sites. The reasons are quite simple and well-known to most properly trained welders. The surface discoloration on stainless steel after welding or even after grindingis oxidation. At too high a temperature, the stainless steel will combine with oxygen to form an oxide layer on the metal surfaceor within the weld. The color of the "stain" is a function of the layer thickness. This will also vary with the type of stainless chosen. The oxidation indicates that the metal temperature when welding was too high..probably in excess of 500C when 315C would have done better, been much stronger and looked like a jeweler had a hand in it. OR it could also be a unwise choise of stainless welding wire or a combination of these factors. It is a simply matter to try different heat and stainless types to determine what will be idea. Improperly chosen equipment can also make a decent weld more difficult.

Sadly, the high heat also destroys the anti-rusting elements in the stainless and weakens the metal eventially causing rust and breakage. Trying to grind off the discoloration or rust makes the weld even weaker. Polishing can sometimes correct the aesthetic effect but will not otherwise address the damage caused by the welding.

Prevention is simple and costless. The Factory simply needs to use the right type of stainless steel welding wire at the correct temperature with the correct technique. That will prevent the stains, keep the metal strong and rust resistant and be considerably more attractive.

There is no cure for any of this after the fact.