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-   -   interior wood trim, surface preparation question (http://www.diychatroom.com/f4/interior-wood-trim-surface-preparation-question-20308/)

copacetic 04-25-2008 01:40 AM

interior wood trim, surface preparation question
 
I have interior wood trim (door frames, baseboards, doors) that currently has latex paint over oil paint. The original paint was oil and someone before me painted latex over it. My question is how do I now paint over this mess?

The existing latex paint actually is sticking pretty well to the oil paint below. There are some places though, particularly in the bathroom, where I can start peeling the latex paint off if I use a coin to get it started. This worries me. Can I just apply primer and then paint over this? My topcoat will be latex semi-gloss and am willing to apply primer first. The question is do I need to prepare this surface before priming.

Should I strip that latex paint off? If so what should I use? Sanding doesnt work well because the trim is curved. Maybe a wire brush? Maybe paint thinner? Does the paint need to be completely stripped or can I just rough up the surface a little bit, and then apply primer, hoping it holds everything together.

If I should strip the latex paint off, should I only do it in areas where it is easy to peel? Most of the house is ok. Keep in mind, if I had to strip the entire house it could take weeks--there are a lot of baseboards. I want the paint job to be good, but I am not a perfectionist. I want to cut corners when it makes sense.

Thanks in advance for your help!

slickshift 04-25-2008 07:30 PM

Welcome to the site

Primer won't hold any loosely adhering coatings...not for very long anyway
The problem is the adhesion and that can't be corrected by putting yet another coat over badly adhering stuff

I'd suggest scraping and sanding any loose or ill-adhering latex off
This could be a big or small job depending...there's no way to know till you get into it
Anything that loosens up with a little scraping or roughing up has to go...and has to go until you get to stuff that adheres firmly

Firmly adhering stuff is OK

Oh yeah, I don't use sandpaper for this type of sanding, I use a sanding sponge

Then you need to clean it up real good, wipe up any dust, and then prime with an oil-based (alkyd) primer

Then you can topcoat with latex
I'd recommend a quality waterborne enamel

copacetic 04-25-2008 08:03 PM

Thanks for your reply slickshift. The sanding sponge barely digs into the paint even when I work at the same spot for a long time. I am using the coarsest sanding sponge they had at Home Depot. Maybe I exaggerated how easily the stuff peels off. You really have to work at it with your fingernail. I also tried a wire brush, that barely works either. Really coarse sandpaper does work to some extent. But not the sanding sponges. The trim is contoured though, so its hard to work on it with sandpaper, it requires a sponge. A scraper does work, but only on the doors obviously-the trim is curved. What about using deglosser or liquid sander or any other solvent?

I am beginning to think this stuff doesnt even need to come off, since a coarse grade sanding sponge doesnt make it break apart. Your thoughts?

slickshift 04-25-2008 08:52 PM

If that doesn't take it off, it's probably on there pretty good

Liquid sanders and deglossers have their uses
This is not one of them

Ask at your local paint store which oil-based primers they have for this
Do not get your primer from HD
You need a good one from Ben Moore, Zinsser, or Sherwin Williams


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