Wrinkling Problems and the "Recoat Window"

not while it's doing it. February 26, 2007

Question
I have used Chemcraft Acrylic AL50 lacquer for the past 12 years with great success. I went to my supplier to get some more product and they told me that the name and number had been changed. I called Chemcraft in Alabama and the secretary said it was the same product with a different name and number. Then I called Chemcab.

We sprayed our vinyl sealer, sanded, sprayed the Chemcab, sanded, and then attempted to spray a second coat of Chemcab. This is where our problem started. The second coat looked like a dried prune. The first coat looked great on the vinyl sealer but would not layout when sprayed on itself.

I called Chemcraft back and the technical guy informed me that the Chemcab was not the same as the AL50 but was closer to a Precat. How can I get a second coat of finish to go on like it should?

Chemcraft has found me some AL50 at another store but how will I know that it will adhere to the Chemcab? I have to come up with a solution because we have about 70 doors to put a final coat on. Any suggestions will be appreciated.

Forum Responses
(Finishing Forum)
From contributor W:
I found the same problem with the pre-cat as you said. The only way I solved it was to change to another product, in fact the same one I was using before they talked me into trying the precat - no more trying something different..

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From contributor J:
In this case the Original Questioner did not make the choice to change. He was just continuing to use the same old product, or so they told him. So how is your supplier going to help? Sounds like you've been a loyal customer for 12 years.

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From contributor W:
I know he didn't make the choice to change. The point I was trying to make was that I found out that Chemcraft's pre-cat does crinkle on the second application. I did not use or know about AL50 lacquer but he said that they used the pre-cat instead of the AL50 for whatever reason. Their pre-cat will wrinkle upon the 2nd application after the first has dried even overnight. It seems to me that the pre-cat was substituted for the AL50 by the supplier.

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From contributor D:
What you are experiencing is known as a recoat window. There is a period of time (the window) where the first coating has begun but has not yet finished cross-linking. This is why you get the lifting. The solvents in the second coat attack the yet to crosslink first coat.

The solution is to either get the second coat on before the cross-linking starts or to apply it after the cross-linking is complete. All pre-cats are like this. You must avoid what is called the recoat window or they will self lift. It’s the nature of the beast.