Safer solvents for fiberglass prep

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rocketsam2016

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Hi folks,

I was pretty surprised to find out that the recommended respiratory protection for working with methyl alcohol is a supplied air or self contained system (https://www.cdc.gov/niosh/npg/npgd0397.html).

It is a pretty substantial component of the solvents recommended for preparing fiberglass for epoxy (denatured alcohol, lacquer thinner), and I'm forced to work indoors with suboptimal ventilation, so I'm looking for the best alternative.

I picked up some 99% isopropyl alcohol which “only” requires a full face mask with an apf of 50 if not using a powered supply (https://www.cdc.gov/niosh/npg/npgd0359.html)

Any reason it won't work as well or are there other solvents worth considering to use inside? Acetone iiuc is probably more hazardous than any of the above?

Sam
 
Just to clarify....denatured alcohol is only 5% methanol and 90-95% ethanol. The methanol is just in there to keep you from drinking it.


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And a good MSA 200LS half mask respirator with Paint and Pesticide cartridges ( OV organic vapor combo cartridge will take care of the vapors) at a reasonable cost. Just remember vapor carts are one shot and depending on the concentration of vapors you are working in is how long they will last before saturation and becoming ineffectual.
 
Just to clarify....denatured alcohol is only 5% methanol and 90-95% ethanol. The methanol is just in there to keep you from drinking it.


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FWIW, wikipedia claims 10% is common (https://en.wikipedia.org/wiki/Denatured_alcohol), and many anecdotal sources on the web claim 50% or more.

Stepping back, though, is there a principled way to know how much safer x% methanol is than pure? I mean obviously it is "safer", but I'm not able to measure or accurately control the vapor concentration in my workspace (the inside of of a home in the city; I use a bathroom with a vent fan to the outside but no window to keep the fumes from the rest of the house), so my gut says that if 100% methanol requires a powered air supply, I shouldn't assume that 10% magically safe with a passive respirator.

Thoughts?
 
And a good MSA 200LS half mask respirator with Paint and Pesticide cartridges ( OV organic vapor combo cartridge will take care of the vapors) at a reasonable cost. Just remember vapor carts are one shot and depending on the concentration of vapors you are working in is how long they will last before saturation and becoming ineffectual.

Rich - every documentation I can find specifically says that a passive OV cartridge in a half face respirator is not sufficient according to official workplace standards for working with methanol.

I've been using a good APF10 half mask respirator with OV cartidges for some time now. In fact I discovered this issue about methanol safety when I was researching cartridges a few weeks ago since my previous supply of the ov cartridges had run out. I've since purchased a full mask passive respirator which should get me as far as APF50 in theory if I'm careful about putting it on correctly, but according to all official documentation I found, that is *not* sufficient for methanol.
 
Several years ago I threw a fit at my university because they were using fume hoods that didn't vent to the roof. Instead they simply recirculated the air through an activated carbon filter. The manufacturer, of course, said it was fine, but I didn't believe them. We placed an open bottle of methanol in the hood and tested the air on the other side of the filter. We could not detect any MeOH coming through. I went from being furious to impressed.

I can't vouch for the efficiency of the organic vapor cartridges on a respirator, but they do contain activated charcoal, which I now know is very good a removing MeOH vapor from air.
 
Several years ago I threw a fit at my university because they were using fume hoods that didn't vent to the roof. Instead they simply recirculated the air through an activated carbon filter. The manufacturer, of course, said it was fine, but I didn't believe them. We placed an open bottle of methanol in the hood and tested the air on the other side of the filter. We could not detect any MeOH coming through. I went from being furious to impressed.

I can't vouch for the efficiency of the organic vapor cartridges on a respirator, but they do contain activated charcoal, which I now know is very good a removing MeOH vapor from air.
That is re-assuring! And for what it's worth it is amazing how well the respirator's work - I never notice the smell.

On the other hand, I frequently feel like my throat feels irritated after prepping fiberglass for epoxy. I don't know if it's imagined or not, but it freaks me out, even though I never smell anything.

All that said, I'm sure you understand how freaky the recommendation is that for personal protective equipment, people working with methanol professionally must use a powered respirator. And, after all, your fume hoods are essentially the same as a beefed up powered respirator.
 
If you really want a high quality professional grade mask I have a MSA Ultra Elite with T-bar adapter for use with MSA cartidge filters I would sell. I even have a MSA MMK papr ( HEPA filters only) I would sell. The Ultra Elite is a full face mask and the one I have is Silicone rubber iirc. I can get more info if interested.
 
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Thanks Rich and Chris!

In my case... I am still working in my home, albeit trying to do so in a segregated area, so I think I'd rather focus on less toxic chemicals when possible over moving to even higher powered protection.

So... any reason not to just use isopropyl alcohol? It's not good for you either, but seems to be a whole lot less bad.
 
I don’t see any reason besides the higher boiling point. That just means it will take a little longer to evaporate.


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