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Paint over the mix?

PostPosted: Sat May 19, 2018 10:35 am
by equant
I've seen recommendations that one should not use the mix on the bottom edges of a build, so that the pmf can wrap around and glue to the wood. I assume that this means that the mix interferes with the glue. However, I've not been able to find any discussion about paint adhesion over the mix. I have some plywood that I would like to use the mix on, and then paint over (with latex house paint). Is that feasible?

Thanks

Re: Paint over the mix?

PostPosted: Sat May 19, 2018 5:42 pm
by GPW
Make some test samples, tell us how it worked for you … It’s how we all benefit !!! :thumbsup:
Paint should stick fine to the mix unless you put so many coats on it becomes shiny Plastic ( it’s only a waterproofer , not a Finish ) … Then you’d have to sand it for Tooth , and prime it first …

Re: Paint over the mix?

PostPosted: Sat May 19, 2018 6:16 pm
by working on it
  • Though I didn't build a foamie, or use PMF, I did paint over the "mix", and also used plenty of Loctite PL Premium Adhesive on it, and can testify to paint/poly/PL all adhering well to it. I used the "mix" to soak into my exterior walls, then poly'd over that, then painted over all, before mounting vent covers (4) on them. When I had to remove and modify one vent, I had great difficulty in getting it off, cleanly, and actually lifted away 2 coats of the "mix", 2 coats of pure poly, then 2 more coats of acrylic enamel paint, as well as most of the outer ply of wood itself.
  • If the "mix" hadn't stuck/adhered to the outer ply so strongly, or the 4 coats of poly and paint, and the PL afterwards, then I would've easily removed the vent cover. I had expected to have at least one coat of coverings give up, before reaching the "mix" layers, but only found that the plies penetrated by it were joined forever together, to all layers bonded to it. I think the key to having all "bonding" so well together was that each coating was either oil-based, poly-based, or both....
  • PL, over paint, over the mix- everything really sticks well.jpg
    PL, over paint, over the mix- everything really sticks well.jpg (161.31 KiB) Viewed 999 times
    once coated with the "mix', the plywood became inseparable from the outer coverings/coatings

Re: Paint over the mix?

PostPosted: Sat May 19, 2018 7:24 pm
by tony.latham
It should be fine––just like using latex over an oil based enamel: Sand, prime, and paint.

T