No Alligators Please

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We are trying to paint some pinewood derby cars with Kryon paint. If we let the paint set for over 24 hours we get an alligator finish on the cars. Any idea what is happening here?
Mike D.
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Krylon only sells about 100 different coatings for various applications, all of which are light on pigment and heavy on solvent.
WAGs- temperature, humidity. ----
- gpsman
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Michael Dobony wrote:

Your description sounds like orange peel. You can google it up for ways to avoid or correct. I strongly suspect you put on too thick a paint layer. Lot of time it just takes several fine coats to avoid this. Make sure you have adequate drying time between coats. May only take a few minutes. Not sure if Krylon, as with other paints, is reformulated to lower VOC's, volatile organic compounds, and if so drying time between coats would probably be longer.
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*I couldn't say for sure, but I am thinking that the resins in the wood have some affect on the paint. You could try using a primer. I think that Krylon puts a helpline telephone number on their products. Try calling them.
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Depends on the particular formula, but it is often better to repaint either before or after after some specified curing time. What does the can say?
One can I just looked at says "Recoat before 24 hours or after 7 days" Another says recoat any time.
Also., putting on coats too heavy makes it worse.
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On Sat, 21 Feb 2009 12:41:25 -0500, Ed Pawlowski wrote:

We are doing light coats and it says to recoat within 1 hour or after 24 hours. There is no problem with doing the recoat within 1 hour. The problem is when waiting for more that 24 hours. This is on top of 2-3 light coats of primer.
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Michael Dobony wrote:

Any chance the primer was not cured? Dried paint in hot sun?
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On Sat, 21 Feb 2009 17:25:51 -0500, snipped-for-privacy@earthlink.net wrote:

Yes, the paint was dried in the hot sun. That might be the problem. Why would this cause problems? It seems that it should dry faster and harder in the sun and give a better finish.
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Or it could give a nice hard outer shell and keep solvents locked inside.
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Paint doesn't really dry--it cures. Chemicals in the paint combine with oxygen (and maybe other gases) from the atmosphere, changing from one chemical to another.
If you dry it in a hot location, the surface skims over, blocking oxygen from the part below. You need a slow, even cure so it all gets done at about the same time. I'm sure you've seen a mud puddle that dried in the sun. You get the same alligatoring.
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Steve Bell
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On Sun, 22 Feb 2009 18:02:07 +0000 (UTC), "SteveBell"

Steve is right, and this applies to painting house exteriors as well.
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Michael Dobony wrote:

That is almost surely your problem. The surface dries hard (too fast)and doesn't allow evap. of the solvents underneath.
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On Sun, 22 Feb 2009 13:24:53 -0500, snipped-for-privacy@earthlink.net wrote:

This would explain a layer dried in the sun, but doesn't explain why a second layer would instantly bubble up before being put in the sun.
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Michael Dobony wrote:

The top layer formed a skin, then the solvents trapped in the earlier layer expanded but couldn't pass through the dry skin.
SOP is to paint each side of a house before/after the hottest sun exposure, for the same reason. Temp guidelines on paint labels are there for good reasons - too cold, it won't cure; too hot, the surface is complete but traps the lower solvents.
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The solvents in the second layer softened the skin of the first and allowed the underlying solvents to move freely. The alligator you see is that softened skin shrinking in place under the second coat.
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Michael, I sure hope you get a good usable answer to this one. I have sprayed paint with conventional guns, airless, HVLP, and rattle cans. I've shot lacquer, oil base, and latex. I've brushed and rolled. I've oil primed, acid primed, latex primed, epoxy primed. I have created some very high quality painted finishes.
My last two projects shot with extra expensive rattle can paint (because it was an important project) alligatored just as you describe. Many people have not read your posts very well, so I will repeat that my project was well sanded and well cleaned MDF. It was primed 3 times with sanding and filling between coats. It was performed in high gloss black with each coat applied as a full wet coat. We waited the specified cure time between coats. The paint was applied indoors, normal shirt sleeve temperatures. There was no rhyme or reason to the alligatoring, it was quite random on the piece; but made it quite unusable. I hate working under deadlines and this thing was eating our lunch because of paint problems.
My solution will be to not ever use rattle cans for important work unless it is the 79 cent (ya, my age is showing) cheapo oil based stuff. If it counts, I can brush lacquer better than the results I've gotten from Krylon.
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try a primer
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Read can on recoat time, in minutes or hours , if you do it wrong solvents eat the first coat. But primer is smart if wood isnt cured or has oils.
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Michael Dobony wrote:

Alligatoring - AKA reticulation - occurs when a new coat is put on one that is not yet dry...the surface of the new coat dries rapidly but the coat under it continues to dry over time and as it does so the newer top coat shrinks and crinkles. The first coat may *seem* dry but is not.
I never used to have this problem with spray paints but sometimes do now. Seems to vary by brand too. I don't know what changes have been made in the formulation to cause the problem but - perhaps - the type/amount of solvent. Perhaps the solvent nowadays softens - thus expanding- the first coat.
The only solution I have found is to spary ALL coats in the first couple of hours OR wait several days before re-spraying.
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dadiOH
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On Sat, 21 Feb 2009 16:21:45 -0500, dadiOH wrote:

One of the cars in question was not painted for a whole week. When sprayed within an hour or so it is fine. Spraying over the primer is fine. A second or third color coat after 24 hours is the problem. I ended up sanding back down to bare wood before redoing my car, but we are having trouble with other cars that need another coat of paint. The yellow is especially troublesome as it does not cover well and needs 24 hours to dry between coats to get it to cover properly.
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