I just recently bought a respirator for me to use when
investing. This is the thing. You cannot use one of those 3-4
dollar jobs with the removable filter in front and the cloth
thing to go up against your face. In order to trap free silica,
you must use a HEPA filter, approved by NIOSH. These are the
more expensive “canister type” masks with the replaceable
canister that screw in. Silica can get rather small, about 5-10
microns. Those cheaper filters are for large dust and will not
stop silica from entering.
The good thing is that you can also use those canister type
respirators when melting platinum and other metals, which do
give off vapors when melting. The one common metal vapor that
those respirators will not protect you against is silver vapor.
Also, don’t use them with mercury. You need a totally enclosed
oxygen system for that. Just wanted to throw a safety note out
Actually, if those cheap masks were made by a reputable
manufacturer, they will say on the back not to use them with
toxic or hazardous dusts like silica, asbestos, etc. It is a
pain to have to buy the more expensive mask, which costs about
$25, but this is my health we are talking about here!! I don’t
want to wake up 10 years down the road with silicosis.