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Hi Marq,

I need help again. I did about 6 coats, but the paint never hardened. I think the problem was that I live in Vancouver where it is very humid during the winter months. I did my paint during the winter.

So my plan is to strip off the old paint and start over again. This time I'll use a dehumidifier between coats to ensure that each coat has hardened before I paint over it.

My question is: what's the best way to strip off the old paint? The last 4 coats of the old paint didn't cure properly ... and it clutts up the sandpaper ... even when I wet sand at 400 grit.

Please help.

John



Hmmmm.... ok... so your paint is still tacky and that is clogging up the sand paper... So if I was faced with that situation I would just stop work and leave the painting alone for two weeks. If you could park it in a nice hot garage, even better. But even being left out on the street or in the driveway where it can get whacked by the sun would help greatly to get the paint to fully evaporate the carrier and harden it up.

I don't think I would try any forced or chemical strippings of the paint at this point. IF you can get it to fully harden or cure by just leaving it alone, that would be better in the long run. IF it should reach a point of hardening where you can finally use sandpaper on it, then you will be almost certainly assured that it is going to be a well adhering base coat when you do get around to sanding it.

I understand what you mean about the humidity of Vancouver being a factor. Humidity does slow down the curing process. In a warm dry climate you can usually apply 'the next coat' within 12 to 24 hours. With cooler or humid conditions, the curing time between coats could go up to 48 hours between 'the next coat'.

IF the coats of paint you apply roll on fairly thin, with the mineral spirit being able to evaporate fairly freely ( due to the warm environment ) times will be speeded up between coats.

IF the coats of paint you apply rolled on slightly thicker.. it will take a little more time between coats of paint ( because the thicker rolling will end up forming an outer skin that will attempt to trap the evaporating mineral spirit beneath the skin. In that case you just have to walk away and give it anywhere from 36 to 48 hours to cure.

NOW... one thing you might want to experiment with is using acetone instead of mineral spirit. The acetone works like the mineral spirit to thin out the paint BUT it has a faster evaporation rate. The fast 'flashing' of acetone would not be good for someone in a warm ( hot ) environment, but in a cooler and more humid environment, the faster flashing of the acetone would actually be like the normal flashing of the mineral spirit in a hot climate.

Overall, I don't think that the paint remaining tacky will be helped by slapping even a dozen dehumidifiers in the garage. At this point heat or time are the key factors that will evaporate the carrier (mineral spirit).

IF the paint was 'ridiculously tacky'... I might try the suicide move that I faced when my trunk initially screwed up. For some reason the trunk had chosen to rebel and went elephantine. And like your situation the paint was tacky. I had resigned myself to just walking away from the project and letting it dry itself hard ( and then I was going sand it back a few coats and redo it ). But in a suicidal move I took one of my clean cloths - thorougly SOAKED it with mineral spirits - and I began wiping down the surface. My oddball theory was that if the paint was not curing... then possibly by overdosing it with straight mineral spirit and rubbing with the cloth with strip the damp layer of paint off a few layers until it reached a fully cured layer ( which would not be as affected by the soaking wet wiping cloth ). In my case it did exactly that. The bad coats of paint began rubbing off. In the end the truck lid lost all the bad coats of damp paint and passed them on to the cleaning rag. I was able to wipe the trunk lid down to one even sublayer of cured paint. I then walked away from the project for three days to let the trunk lid fully recure and evaporate all the mineral spirits that I had hit it with. When I came back to it... it was dry and hard - and so I hit it with a 400 grit sandpaper, wiped it down with a clean cloth with mineral spirt, walked away from it for the evening ( to let the wiping down evaporate ) and the next moring I applied a new coat of paint to that trunk.

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