Technical Rattle Can vs Spray Gun

Did you add the hardener as well when you reduced it?

 

Catalyzed paint does not dry. It hardens.

Rattle can dries.

Catalyzed paint without the catalyst (hardener) is just rattle can, with extra steps.

Body filler without hardener would dry out, but it would take months, not minutes.

 

Did you use a hardener? Acrylic enamel can be used with or without, but if you add hardener it will likely go dormant at 60 degrees or below as that's the temperature where most catalyzed paints go dormant and any curing reaction stops. AE will still dry by evaporation during low temps, but when its catalyzed that just makes more of a mess than if the entire mix just sat there and waited for higher temps.

Another potential problem is the reducer used in AE for spraying. Enamel reducer, mineral spirits, and similar hardware store thinners will not work and will cause problems. Acrylic enamel reducer is the preferred thinner, and high quality lacquer thinner (the type that costs $50/gal or more these days) can be used if AE reducer isn't available.

The only real solution to any paint that hasn't dried or cured to the point of safe handling in a couple days is to strip it off and go again.

 

If you are in the north east the cold and damp can be challenging try moving it indoors near a heat source like a register or wood burner if the tank has been aired out enough, safey first if your out west try the sunshine...


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some reasons the paint may be slow drying:
painting over not thoroughly dry primer.......especially epoxy.
too heavy a coat. top skins, trapping solvents.
multiple coats sprayed too soon. first coat "to touch" before second etc....
too cold. as said, chemical reactions stop at near 50 degrees.
not enough air flow. solvents trapped in the building.
mixed improperly, too much or too little hardener. or lack of hardener.
also paint mixture not stirred enough, hardener never mixed.
wrong hardener.
old hardener.
shit materials.

 

Thanks for all the insight on this paint challenge of mine.

Not knowing what paint to choose all I knew was to stay away from Lacquer. I took the advice of the “paint expert”. He pre-mixed the paint & reducer together in one can, so it would make it “easier to try out” and not have to buy a bunch of stuff for one product. They didn’t have hardener smaller than a quart size, so I passed on it as I was told it would only take a little while longer to dry without hardener.

The spec sheets on the product said it should have been dry in 8 hours even without hardener. Id rather not strip the tank & start over but I don’t want to wait a month or more for it to dry either. The garage temperature was always over 64 degrees for the first few days then I bumped it to 68 for a few days & today to 75 degrees. I also put a fan on it & one of those oil-filled electric radiator heaters below it. The tank had the heater on it intermittently for 3 days and the last 24 hours constantly. The tank is safe to heat as no gas was introduced after cleaning it. Tank temp is 78 at the highest point & 105 at the closest point to the heater.



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hmmmm?
so it is not the temperature.

 

The paint is definitely not drying, I took a look under the tank & found it had grabbed some overspray off of the 2x4 it was resting on.

How long should I wait til one decides it’s just not gonna dry/cure? If it doesn’t then I assume one has to strip it. If so what’s the best way? Is there a way to do it without going down to bare metal? It wasn’t at bare metal before except for a couple spots.

Then if I’m going to that level of work, I’m never using my local NAPA for paint so where should I go & what should I buy?


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Yeah, definitely not a temperature problem, and can't be related to hardener problems either.

That pretty much leaves a problem with the paint itself or some contamination on the surface of the tank.

What did you use to prime the tank? A lot of spray bomb primers are incompatible with automotive paint.

What did you use as a degreaser to wipe the tank down prior to spraying the acrylic enamel?

Assuming you didn't do anything obviously wrong, if you have any of the paint left you could take some small piece of metal and spray it to see what happens. If you used spray can primer, don't use it for the test. Spraying on bare clean metal is fine when you're only checking to see if the paint dries as it should. Just make sure whatever you spray is clean and oil free. If it doesn't dry, that points to a problem with the paint itself.

 

X2 I use bedliner paint for stuff like that.

 

He didn't use hardener.

 

True, and that's why the problem can't be related to hardener. I assume you know acrylic enamel can be used with or without hardener.

 

After using urethane based auto paints I will never go back to acrylic enamel. The urethane paint is tougher sticks better and cures up faster.

 

Wash it down with reducer and start over. Paint the whole thing at once. Hang it up from the fill tube. Use hardener.

 

Sure, but you risk exactly the achieved result.