SWMBO and I are in the process of redesigning our living room. The mantle over the fireplace is stained red oak with a poly finish. I would like to be able to fill the grain so that when I paint it I will have a smooth finish. I looked at a grain filler at the paint store and it said that any previously finished wood needs to be stripped down to bare wood before applying the filler. Does anyone have any ideas about how to prepare the wood short of stripping that will give me a smooth base on which to apply the paint. Thanks for any ideas.
Tim
Replies
mytthor,
There is a technique where you apply coats of shellac and then sand to eliminate all dimples, etc. followed by primer till like glass and then paint. I have only done this once and it did work. I applied 4-6 coats of shellac, sanded with 400 grit and water...wiped down, inspected, applied more shellac, sanded with 600 grit...wiped down, inspected....from there it really depends on how smooth you want it.
Edited 3/7/2006 6:19 am ET by BG
BG has it right, though since you plan to end up with paint instead of a clear finish you can accomplish the grain filling with a paint primer instead of shellac. You will need to get a good "tooth" on the poly by sanding with 220 or 320 grit sand paper. Then apply a good paint primer that will sand easily. Apply, let cure and sand smooth, stopping each sanding when you begin to cut through to the underlying coat. When you can sand smooth without shiney "dimples" from the grain you are ready to apply the top coat. Oil based finishes are likely to sand better than acyrlic or latex, and top of the line is generally worth paying for in paint.
I haven't done this sort of thing anytime recently so others will have to advise about particular primer/paint systems.
Oak is a fairly rough surfaced wood. Even after filling and sanding there will be a bit of grain left visible but that shouldn't be a big issue. You could prep the surface first with Liquid Sandpaper. This will cut the gloss on the current finish and help with the adherence of following procedures. I'd just use some ordinary nail hole filler like a spackling compound, Zar wood patch, something about the consistency of joint compound. Not a wood dough. I've actually used joint compound on oak but it can have a tendency to swell with moisture. Apply with a putty knife, let dry, sand with 220, prime with a good quality oil based primer and top coat with an oil based paint. As long as it's still available, I like Benjamin Moores Satin Impervo, it flows out nicely with a minimum of brush marks and has a porcelain like look and feel.
Beat it to fit / Paint it to match
Someone over at Breaktime just mentioned the same kind of problem - paint over poly. There was a product mentioned and you might find it if you search.
BIN 123 is a shellac-based primer that sands nicely. It's thick, and to fill oak you'll need something thick. Because it's shellac-based, it dries fast, can be easily stripped later, and sticks to most anything.
Thanks for all the ideas for finishing this project. It is great to have all of this support.
Tim
Scrape bondo on it and then sand off, Thin the bondo down a litter bit after you use the hardener.
_lou
Edited 3/11/2006 6:50 am ET by loucarabasi
There used to be a product called Nitro Stan which came in a large tube like toothpaste. It was similar to a thin bondo (it was one part, no mixing )and was used for filling scratches and chips in paint on auto bodies (as part of the prep for repainting). I believe it is still available and can be found where automotive paint products and auto body repair supplies are sold. Just apply with a plastic spreader, let dry and sand. One or two applications should be enough. Its worth a try.
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