Petit paint and 3M 4200 fast cure caulk

[Tedman]

We just painted a 32ft Chris Craft as well as had to do some plank replacement on it. We caulked all the seams with 3M 4200 fast cure caulk. We went through over 40 tubes of caulk which calculates to alot of $$$$$. The boat was primed BEFORE the caulk. So...........we painted the entire boat with Petit paint. This was a Thursday. We came to work the next Monday to see that the paint on the caulk lines had not dried at all. Its been over a full week now and the paint is still wet on the caulk lines. Is there anyone whio has experience a same type situation or who knows how to remedy this problem. Any advice is appreciated.

[Wild Wassa]

Tedman, solvents have yet to dissipate, from the 4200 which has slowed the oxidation of the paint. It will happen. Has the paint distorted over the 4200? Oil based enamel can take months to cure, without other solvents slowing the process. The solvents can take a while to dissipate now. You have only lost time hopefully. If the paint doesn’t distort over the 4200 it is only a time warp. Good luck. Oil sticks to plastic.

If you had added a catalyst to your paint and had the same situation, problems for sure. I've seen similar with oil based enamel over different calks. Others will know as I do not use 4200.

Also, if the temperature dropped and stayed cool in the boat shed, this could have slowed the setting, oxidizing(a slow process at best) and kicking off the curing, the hardening. The paint is more oily to touch than wet. The paint can remain soft for weeks but eventually hardens up, to normal.

Keep poking it. The finger nail test.

Warren.

[ 05-23-2004, 10:14 PM: Message edited by: Wild Wassa ]

[Scott Rosen]

I'm curious about a few things tedman.

Why did you choose 4200 for a seam compound?

Why did you prime before laying in the compound? It seems to me that one of the benefits of using a PU adhesive/sealant is that it stick well to wood. By priming first, you loose the benefit of the strong bond, because the compound will now only hold as well as the paint.

If I'm not mistaken, the 3M polys cure by moisture. It's possible that if you have been working in a very dry environment, and didn't give sufficient time to cure, that you didn't wait long enough before painting.

It's also possible that if you used a Petit polyurethane paint, that there's some funky chemical thing going on between uncured 4200 and the paint.

If I were you, I'd call both the 3M and the Petit tech support. They should have the answer for you.

[pcford]

Well, you definitely will not want to hear what I have to say.

I did the procedures to which you refer on a client's boat (a Chris cruiser) last winter. It had been out of the water and the seams had opened up. The seams had been routed. A previous boatwright on the project had put 5200 polyurethane in the open seams. It took a fair amount of effort to get the material out of the seams. Only way to get it out is to cut it out with a razor. Tedious. Polyurethane should not be used as a seam compound. There is some danger of the planks buckling. Polyurethane is too hard for use as a seam compound. I replaced it with polysulphide. Actually, Chris topside construction (batten seam) should not require seam compound if the planks were replaced correctly.

And yes, if the material, polyurethane or polysulphine has not gone off thoroughly, the paint will not dry. But there may be larger problems here.

[Dave Williams]

Don't know the chemistry as far as how 4200 and 5200 are different, but I posted a thread some time back about painting over 5200. The Chemist replied and advised to paint while the 5200 was still tacky. I did a test piece and paint cured fine. I soaked the piece for maybe a month then threw it out in the snow and then soaked it again. It's now gone through some summer weather and still seems very well stuck.

I can't seem to find that old thread. If someone can dig it up I'd love to read it again as I'm about to do it for real here soon.

[Dave Williams]

Found it. The thread is called "bottom paint adhesion to 5200"

[Dave Williams]

Bump. Thought I'd bring this back up quick since it seems related to the new 4200 thread.