Can you suggest a good silica free cut down product?
Out of curiosity, why?
The main concern I’m aware of with silica is silicosis, caused by
chronic inhalation of crystaline silica, such as found in casting
investments and some ceramics materials. But the “silica” normally
used in polishing compounds, such as brown tripoli or white diamond
tripoli, is not that form of silica. It’s diatomacious earth, the
fossil remains of tiny seaborne diatoms, a form of algae (thanks
wikipedia). While this is still silica, it’s mostly an amorphous
form, with only a small percentage being the crystaline form. In the
polishing compounds, it’s all held together with wax or grease based
binders, which also reduces the airborne amount of free floating tiny
crystals that can be inhaled.
Yes, there is a small risk if you have no protection from it, but
even with the pure crystaline silica found in things like platinum
investments, it takes long term chronic exposure to lead to
silicosis. With polishing, if you’ve got a decent machine with dust
collector, the amount you’d be inhaling would be miniscule, and a
simple dust mask could cut that to zero. And since silica is
generally pretty inert to the body in terms of reactions and the
like, I’m curious what your concern is about a silica free cut down
compound? With normal care in use, you really don’t have much in the
way of a risk to worry about.
(That’s not the case with casting investments, which can expose you
to much higher levels of crystaline silica in the most damaging
particle size ranges)
So. Just being curious.
But also, an answer.
While the brown and white diamond tripoli compounds both are silica
based (as is, I think, bobbing compound, though I’m not sure of
that), I’m pretty sure that greystar compound is based on emery
(aluminum oxide) abrasives. Again, you should check that, but I’m
fairly sure. The other ones that come to mind are some rather
expensive, but wonderfully effective, platinum polishing compounds
sold by a number of dealers. Gesswein was the first to import them
from Japan, now others do too, including Otto Frei, and others. These
are aluminum oxide abrasive compounds available from an 800 grit
(which works very well as a tripoli cutting compound on all metals,
not just platinum), in a number of steps all the way up to an 8000 or
higher grit, which are used as high polish rouge compounds.
I like these compounds, but be warned, they’re rather costly. Easily
ten or twenty times the cost of things like tripoli and red rouge…
Oh, and for the record, no matter what types of cutting and
polishing compounds you’re using, silica based or something else, you
should be working such that you’re not inhaling compound. If your
dust collector isn’t fully effective (many of the less costly units
are not perfect, especially with larger diameter buffs), and it
doesn’t collect all the airborn polishing dusts, then wear a mask.
When you’re done polishing, you can have dirty fingers. But not a
dirty face. If your face looks in the mirror like you’ve been down in
the mines, then you’ve been breathing stuff you would be better not
breathing, no matter what the compound is. You don’t need some big
fancy filtered respirator with buffing compounds (though those can be
a good idea with casting investments). Just a simple disposable dust
mask is fine. 3M makes a number of types, and they’re not that
expensive.
Peter Rowe