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Respirators for use with silica and other things


#1

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
there.

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.

Marshall Jones


#2

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 there.

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.

Marshall


#3
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. 

I have one that cost considerably more than $25 with two screw in
filters and a glass face shield, for the reasons you stated.

I use those cheap masks to filter my rhodium plating solution.

Paf Dvorak


#4
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. 

You will have a hell of a time heating platinum to the point of
giving off a vapor as its boiling point is well beyond the
capability of oxy-fuel torches at 6917 F. Likewise almost all the
metals we use as goldsmiths/metalsmiths have very high boiling
points where they could turn to vapor.

Silver 3924 F
Copper 4643 F
Gold 5173 F
Nickel 5275 F
Palladium 5365 F

In fact the only metals one has to be concerned with vaporizing with
a torch are :

Mercury 674.11 F
Cadmium 1413 F
Zinc 1665 F

Even other low melting temperature metals have very high boiling
points:

Lead 3180 F
Tin 4716 F

Even gallium which will melt in your hand has a boiling point of
3999 F

So if you are using a torch or other flame to melt metal you will
have a very difficult if not impossible time trying to produce metal
vapor with the exception of mercury, or cadmium, and zinc bearing
alloys. You could possibly boil lead but that is almost at the
melting point of platinum.

While there are other potential fume concerns when melting, metal
vapors is typically not one of them except for zinc and cadmium
containing alloys.

James Binnion
James Binnion Metal Arts


#5

Bob,

In some ways you are right and in others completely wrong…

Which is better a N95 bubble type disposable mask you find at
hardware store or a 200$ certified canister type mask? The answer is
the one that fits you correctly and gets a proper seal.

The best mask in the world is next to useless if you do not have a
proper seal. If you are looking for a good mask 1- shave off the
beard and mustache (if you have one) and then have the mask properly
fitted to you.

Then be trained in how to maintain and test your mask. If the bubble
mask is sealing to your face and the expensive mask is not then the
$3.99 mask is better

OR

Spend an obscene amount of money and buy a human breathing rated
compressor and get a positive pressure mask and who cares if it
leaks a little

Kay


#6

when the difference is only 15 dollars what do you think the correct
answer is? You have 2 lungs that is it. I use my 25 dollar one all
the time actually using it made me transition into an apnea full
mask very easily so do what is best. I have to replace mine lost in
the fire but will be buying it first along with full face shield and
all of my casting gloves etc (waves at rio)when we finally move to
our new home which is closer and closer. Finally found a perfect
house on 4 acres I gave up acreage wants becasue this house has a
full basement work studio in it so all of the electrical and
exhausts are already there and it is walk out to the garage… ohhh
droool lol

Teri


#7
Likewise almost all the metals we use as goldsmiths/metalsmiths
have very high boiling points where they could turn to vapor.

Well, yes Jim, but the important thing is not boiling point, but
vapor pressure. After all, a dish of water will evaporate on your
table, even though it never got near the 212f needed to boil.


#8
Well, yes Jim, but the important thing is not boiling point, but
vapor pressure. After all, a dish of water will evaporate on your
table, even though it never got near the 212f needed to boil. 

“The boiling point of a substance is the temperature at which the
vapor pressure of the liquid equals the pressure surrounding the
liquid and the liquid changes into a vapor.”

Those numbers I gave are the the liquid to vapor transition
temperature @ atmospheric pressure. That is the definition of
boiling point.

What you are referring to is evaporation which is a surface effect
where a molecule of the liquid would be knocked off of the surface
by being struck by by another molecule. Metals atoms are much more
strongly bonded to each other than water atoms are so it is much
harder to knock one off the surface of the liquid. This is why
metals have such high boiling points, it requires a lot more energy
(heat) to break the bonds between atoms. It is also why it is not so
easy to get metals to evaporate. Even at a 10 mili tor vacuum the
boiling point of copper is over 2000 F it is not so easy to get a
metal to evaporate.

So again you have no worry about metal vapors at the temperatures we
are dealing with other than zinc, cadmimum, or mercury.

James Binnion
James Binnion Metal Arts


#9

Silver 3924 F
Copper 4643 F
Gold 5173 F
Nickel 5275 F
Palladium 5365 F

Oxyacetylene can easily reach 5400 F. Some reports say over 6000.

Al Balmer


#10
Oxyacetylene can easily reach 5400 F. Some reports say over 6000. 

That is the flame temperature not the real achievable temperature in
use. Then there is the minor problem of what you are going to boil
the metal in. Alumina crucibles are molten at 3762 F, silica at 3137
F. You could do it in a zirconia crucible as it will not melt until
4919 F though.

The point of the post was that you would have to work real hard to
set up a situation where you could possibly vaporize the metals we
work with. Again the exception being zinc, mercury and cadmimum.

James Binnion
James Binnion Metal Arts


#11

Just to emphasis the point that James makes, as someone who has
spent his entire working life working for different silver alloy
manufacturers, the two elements that we add to silver which give
problems in terms of ‘burn off’ when creating different alloys are
zinc and cadmium. There is no way that you should contemplate
melting cadmium these days without full respirators and good local
exhaust ventilation going through a plant which can reclaim the
metal fume.

Mercury is the only other metal to be aware of which but this should
not be something you would encounter unless you are looking into
reclaiming precious metal using an amalgam type process.

Charles Allenden


#12

Is it safe to assume all current mill products including solder are
cadmium free? What about germanium - any issues there? And. what
about flux fumes? I tend to be more concerned about this stuff in my
older age. I got this far without killing myself and wish to make it
a while longer. I guess the assumption should be there is something
"bad" present when you are soldering and just shut up and vent - the
rest is academic.


#13

In the US if it contains cadmimum it must be marked that it contains
cadmium.

Germanium is not a problem its boiling point is 5131 F

Yes, any torch work should be done in a well ventilated workstation.

James Binnion
James Binnion Metal Arts