Painting black coated formply

[Dengue]

Can anyone please advise on how to paint black coated form ply with an oil based paint for putdoor use?

I have epoxied the exposed bare ply edges, and now want to paint the whole thing.

[snowyskiesau]

If it's the phenolic covered stuff, forget it!
The only way I could get anything to stick was to remove the phenolic/black coating which makes using the formply a bit of a waste.

[rod1949]

[Bob38S]

I thought we had already been down this road.

https://www.woodworkforums.com/showthread.php?t=180557

[Dengue]

Thanks Bob, I had forgotten all about this thread. After reading the responses before, I must have put it in the too hard basket, and now the need to do this has arisen again.

My apologies, another seniors moment

[Bob38S]

Not a problem.

Hope you get it sorted satisfactorily.

[soundman]

As people have mentioned the phenolic coating is a problem...it is intended to stop stuff sticking to the ply.

All is not lost.
A random orbit sander loaded with 120 gritt will get you there...but you will need plenty of disks, because this stuff is hard.

Depending on where the form ply has come from the coating will vary.
The Australian made form ply from a few years ago, had a pretty thick coating and realy took some getting thru, some of the stuff we are seeing comming out of asia the coating is pretty half hearted and not as much work.

As far as "getting a key" even a good scratch pattern on this stuff will not guarantee good long term adhesion, particularly with lower order primers.

You need to keep sanding till you are thru most of it and you are seeing only remnants in the grain.

Personally Id be using a thinners bassed primer like "wattyl super etch"....it is my "go to primer", because it sticks to lots of things better than other primers.

Yes I know its a spraying primer, but I'd be putting the first coat on with a brush and rub it in hard....yes you need to work fast.

light sand to flaten the surface and second coat sprayed would be my choice.

cheers