Isocyanates in paints/thinners

[seafox]

We had a discussion a little while back about varnishing.
http://www.cruisersforum.com/forums/...ead.php?t=2603

I am using a 3m double cannister mask to roll a two pot ureathane (international perfection) that contains isocyanates. The mask has 3m 6001 cannisters.

Does anyone know how long the cannisters are supposed to last?

I've been to the 3m site and its all gobblygook.

Should I buy new filters each job or does it last longer than that.

Apparently iscoyanates can't be smelt. The stuff really pongs and I cant smell anything with it on yet.

[seafox]

I didn't mean I was using the mask as a roller by the way

[seaclusion]

Seafox,

The agents in two part polyurethanes are not terribly toxic unless they are atomised, ie. sprayed. The volitile compounds that evaporate into the air are no more toxic than the volitile compounds in any other paint. Wearing a mask is a good idea for any painting job, but if you are not spraying, don't get too hung up about it. The canisters should last until you can smell the volitile compunds, (thinners, carriers, dryers).

Richard

[seafox]

cheers. Can't smell a thing through them yet but sure pongs without the mask.

[ssullivan]

Seafox, to put it in perspective, I was able to easily use one set of cannisters on my *entire* 9 month refit project: varnishing, bleaching, sanding, drilling FRP and even things like stinky work on the head.

You will likely be fine for your whole project, or as Richard says above.

I used AO Safety brand, but they are likely the same.

[hellosailor]

Sean-
Find a comfy chair and call 3M Product Info 1-800-364-3577. That one number can and will eventually route you to any 3M division for information on any product they make.
The answer may be "it depends on how intense the fumes were" but I think they'll be able to do better than that.<G> I wouldn't be surprised if there was some kind of color indicator or more quantitative way to tell.

Whether the AO brand will be the same...dunno, sometimes there's a reason that 3M costs more. Sometimes not.

[seafox]

They have a 3M program online that works it out for you. I think it would be easier to operate a 747 jet than the program. You need to know how many ppm you are breathing (I lost count at 99999) and what chemicals are in what you are using. You'd think that they would give a rough guide (say 30 hrs or something like that). There are a heap of brochures etc that come with the mask but really a lot of nothing in a lot of different languages.
About to go in for the 5th coat. (hold breath........) Be out at 12pm.

[savvy]

Seafox, I'm pretty sure isocyanates do not get filtered by any masks. I was told you need a separate air source to spray two pack paints. I don't know about rolling on though.
mike

[seafox]

That's what I have read. Coat number 5 has been done. Going back into the smelly garage at 3pm. It is internal access so we are shutting all the doors in the house and living at the other end to the garage.

[seafox]

6th coat finished......yahoo.

Leave it now for a couple of days then a light sand and start the 2 pot Perfection. About 5 coats with a day drying in between.

[hellosailor]

A fast look online suggests NIOSH and OSHA both want forced air respirators only, and that only 3M makes an isocyanate rated filter. With the catch being no sure way to tell when it is ineffective, and sensitivity issues after exposure.

"Ideally, an air purifying respirator with an end-of-service-life indicator (ESLI) should be used, but none currently exist."
http://www.osha.gov/SLTC/isocyanates/mdi/mdi.html

And what NIOSH calls their "brochure" on the subject, 450+ pages haha.
http://www.cdc.gov/niosh/npg/pdfs/2005-149.pdf

Seems like there's enough concern to really want a moonsuit for this stuff.

[Alan Wheeler]

Actually Seaclusion is spot on. The only time you need to worry about iso's is when you spray the paints. If you read the instructions, most manufacturers suggest you do not spray two pots unless you really no what you are doing and have the correct safety gear. Iso's don;t get taken up into the air by solvents and so the main thing you are safegaurding yourself from is the solvent fumes.
the filters to use are activated charcoal. These cartridges usually have a recomended replacement time on them and I think that was 12mths, but they will actually last for years. I just changed mine a few weeks ago after some 10yrs of on and off use. Lots of use may require it more often. but for solvents, if you can smell anything, it needs replacing.
Activated charcoal has a surface area in the astronomical figures.
When you do spray iso paints, it is recomended that a pressurised breathing unit be used. The charcoal filters will actually filter out iso's, but you only ever need one droplet of this stuff in your lungs to cause you problems later in life. So better protection is strongly suggested.
Iso's were used in car paints manymany years ago. I know one ole guy that argues, "i've bin sprayin this stuff for 40yrs and it aint hurt me any". He only uses a regular filter. I have also sprayed the stuff with regular filters. i wouldn't do it if it was my job, but it has usually been very short sprays. I don't ssssseem to hhavvvee annyyy pppproblemms

[Alan Wheeler]

Actually I should add, make sure you wear gloves. The stuff that can cause you the most harm is the Hardener. It is nasty nasty stuff if you get it on your skin.

[hellosailor]

Wheels, that OSHA URL I posted also mentions that apparently the spraying process is enough to create aerosols all by itself, so the solvent isn't the only thing that's airborne. Given that, the variation in individual reactions, and the lifetime retention of sensitivity after exposure...I mean, who wants to get exposed to all that stuff when it doesn't even let you glow in the dark?!

[Alan Wheeler]

Yeah the iso's are solid particles not solvants, so yes that becomes an aerosol. Then of course there is the hardener/base still wet that would also be wafting around the room.
I have often wonderd. I drive past a few car panel repair shops and you can smell the solvent in the air. Of course, the paint booth has a huge extractor fan, but it all just goes outside up into the air. So if i can smell it, then there must be other harmful particles in the air that I am breathing.