Oops! Forgot the Catalyst

A finisher grabbed the thinner instead of the catalyst, and now the coat won't cure. Fellow pros suggest stripping techniques, as well as ways to catalyze the uncured coat in place. January 13, 2006

Question
I think I must have reached for the thinner rather than the catalyst. I have some doors and boxes that I sprayed with M.L. Campbell Resistant a few hours ago. They are still sticky and look glossy but the finish was satin. I am pretty sure there is no saving them. My first thought was to spray everything with a wet coat of thinner and catalyst but I know better than that. My question is how can I clean this goop off? It is only 12 doors and a few boxes but I hate the idea of starting over.

Forum Responses
(Finishing Forum)
From contributor A:
Wash the down with lacquer thinner. Itís a bad situation but better to correct it now than after it is installed.



From contributor B:
There is a workaround for this. It is not sanctioned by MLC and there is a chance that you will be left with a finish that will not perform or be as durable as you will need it to be. Try the workaround, and after a couple of days, check to see how durable it is in terms of scratch resistance and how well it does on an acetone rub test.

The workaround is to shoot on a layer of slightly over-catalyzed material. Thin it down so that you do not have dry mil thickness issues but go ahead and add in more than the 10% catalyst that you are supposed to add in a( the catalyst before reducing the coating, as always). I am guessing that 13% will be enough to kick the coating underneath and that's what you want. Your topcoat will be catalyzed and the excess catalyst will kick the coating underneath and start that coating with the crosslinking process that it needs. Then, when all cured (after two days it is 85% crosslinked and that's enough for all purposes), scuff well and lay down a good and proper coat. Stay within that dry mil thickness range of 4 - 5 dry mils. That's your final measurement limit.



From contributor C:
Wash them down with lacquer thinner or try MEK (home depot) and just start over. 90 minutes of wiping off the goo, letting them dry and then a quick sanding and you're back to a clean start. That's what Saturday mornings are for! Just another thought - we had this same thing happen (Resistant staying soft) and figured out that it was because one of my guys had shot a 6 or 7 mil coat and then put the pieces directly under one of the warm, forced air ducts. I think it dried and cured out the top (we didn't even get solvent pop) and trapped a couple of wet mils below. We stripped all but one panel because I wanted to see what would happen. It was fairly hard in about a month but after that I just threw it out.



From contributor D:
Cut a quart of thinner with 12% catalyst and spray a small area. Or even try to recreate it on a sample. If it flashes off too fast, add a little retarder. This works. I would still do a sample.