isocyanates

D

Dman

AzB Silver Member
Silver Member
I'm still in a learning stage and have a few questions on clear coats.
My main question is about isocyanates. I understand the dangers while spraying, but is the danger still there during the drying process. If so at what point is it safe? I also have read some study on isocyanates re-release due to heat generated during sanding. Any info is greatly appreciated.

Dan
 
well... your shouldnt be sanding that fast. if your clear getts too hot it wil bubble and be ruined. took me 5 times on the same cue to figure that out
 
I believe Dan is referring to acrylic urethane finishes (auto clear-coat) and not super-glue finish.

Isocyanate gas is the one of the by-products that are created as a result of the reaction that takes place when combining both parts of auto-clear. It continues to evaporate into the atmosphere, as the finish cures, until the surface has hardened. Sanding of the surface will allow further escape of the gas but to a greatly diminished degree. Adequate ventilation and the use of a respiratory mask specified for 'organics' should be considered mandatory when shooting the finish due to the concentration of the gases. When moving to the 'wet' sanding process, adequate ventilation, IMO, is all that is required due to the diminished concentration.

We're talking about cues here which have a relatively small surface area. If you were wet sanding cars all day without a mask, you could have a problem.

Far too many users of auto-clear take the inherent dangers of it's use far too lightly. It's better to be safe than sorry.
 
Yes auto clear. So it is still a danger until it has hardend to some degree. So I should keep my fan system on thru this drying period also?
 
Dan,
A fan shouldn't be necessary during the curing period because curing begins the instant the reaction is initiated. Because of this, the mtrl. has a very short 'cup' life. You need to empty the gun within 1 hr. (depending on brand of auto-clear) or you'll be buying another gun. The finished surface will 'skin' or 'flash' within 20 mins. or so and will greatly diminish the gases escaping from the surface. It's when you move to wet sanding that you open the surface again. That might be a good time for the fan.
 
if you wet sand it starting with 1000 and go up to 2000 you reallys shouldn't cut that much paint off.i really wouldn't worry about it too much.spraying is the dangerous part.when the paint atomizes is when you need to be really careful about breathing any.
 
As mentioned the worst is the spraying set up. Most companies producing the paint recommend a fresh air respirator.
Most two part urethanes will out gas for a long time.
 
BarenbruggeCues said:
As mentioned the worst is the spraying set up. Most companies producing the paint recommend a fresh air respirator.
Most two part urethanes will out gas for a long time.
Click to expand...

Thanks Dave , KJ and Mason and All who responded.

I have a down draft booth set up and fresh air during spraying. I feel from the answers That it would be correct to keep my booth fan system running thru this drying period do to the out gassing. Is this correct? It what point do you feel safe in shutting down fans and opening doors or removing cue from booth?
 
Dupont says don't use any wax on new finish for about 3 months....I assume because of out gas. I really think once it's flashed over the worst is behind you even though you will smell it for quite a while after.

Of course this is just my opinion and all the usual disclaimers are in effect...
 
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