Paint over Poly?

[Brian Tymchak]

Hi all,

I have a friend at work who mentioned that she wanted to have painted base and door trim. She currently has the ubiquitous poly-over-stain trim. She wondered if she would have to strip the finish off the trim to be able to paint. My first reply to her question was I thought it might be easier to pull all the trim and start over with some of the new urethane trim than to strip the boards.

But if there is a way to actually paint over the poly with some formula of primer/paint/etc, that would be a lot easier and cheaper.

Anyone know if this can be done?

Thanks, Brian

[Mark Kornell]

Brian,

Zinsser's BIN primer will stick to just about anything. If the trim is dirty, clean it with a TSP solution first. Then use the BIN primer, one coat should do. After that, paint away.

[Jason Roehl]

Sand, de-gloss (I like the Krud Kutter version, but I dilute it 1 quart to about a gallon of water), then prime with a high quality bonding primer. Once all that's done, then all the nail holes will likely need to be filled or re-filled, and all the joints, seams, gaps, etc. need to be caulked. Of course, that means all the walls would need to be cut-in again, too...

Anything less looks like a bad DIY job.

[Brian Tymchak]

Thanks guys! Really appreciate the advice. I will forward the info on to my friend.

[Brian Tymchak]

Sand, de-gloss (I like the Krud Kutter version, but I dilute it 1 quart to about a gallon of water), then prime with a high quality bonding primer. Once all that's done, then all the nail holes will likely need to be filled or re-filled, and all the joints, seams, gaps, etc. need to be caulked. Of course, that means all the walls would need to be cut-in again, too...

Anything less looks like a bad DIY job.

Jason, quick question - you mention sanding - is that to remove the poly layer completely or just enough to rough up the surface for adhesion, with maybe a 150-ish grit?

Thanks, Brian

[Art Mann]

All I can say is I had a couple of Adirondack chairs on my front porch that were varnished with Minwax Spar Varnish. The finish started to degrade almost immediately. I eventually cleaned them up and lightly sanded the varnish. I painted the chairs with acrylic latex house trim paint and they have remained nice looking for a couple of years.

[Jason Roehl]

Jason, quick question - you mention sanding - is that to remove the poly layer completely or just enough to rough up the surface for adhesion, with maybe a 150-ish grit?

Thanks, Brian

You got it. 120-180 grit to give the primer some mechanical bond; just a quick scuff-sanding. The de-glosser then serves a double purpose--it does about the same thing chemically, but by doing it after sanding, it cleans up the sanding dust as well.

At the end of the day, it was one of the paint projects I really disliked (going from stained/varnished to painted). Customers always had a very hard time understanding the labor necessary to take old, dark trim with lots of defects hidden by the darkness to a bright, white new-looking trim package like their friends just got in their new house. Then, if they were paying the high price, they always thought they were getting a flawless Rolls Royce, when they were really paying for a Buick...

[Jim Becker]

In addition to the de-glossing that Jason mentions, I've also had good luck using a high-adhesion primer (SW in my case) to allow for application of new paint over very glossy existing trim. It's a lot less work than all the sanding...

That said, my application (pardon the pun) was over glossy paint, not "poly", so I'd have to indicate that Jason, because of his background, likely gives the best advise here.

[Brian Tymchak]

Thanks again guys! I'm learning a lot here.

[John Goodin]

I have used a liquid sander deglosser similar to what Jason mentioned for a closet door jamb. Much to my surprise it worked great and simplified the repainting process.