painting over moldings and doors which have polyerithane finish

I’m painting over moldings and doors which are wood with a shiney polyerithane finish. i’ve been sanding with 220 paper (this is what the guys at lowes recommended) and it’s taking forever. I want to know…

is this totally necessary or can i just paint over the polyerithane?

if the answer to the above is no, then

  1. should i be using a stronger sandpaper?
  2. do i have to scrap off all the polyerithane or just roughen the surface up so the paint will stick better?

thanks guys.



It’s necessary. I use an electric palm sander with 180- or 220-grit sandpaper. You really need to scuff up the polyurethane so that the primer will adhere to it. After you prime it, paint it with your top coat.


Ryan, Sometimes I use a deglosser to prep. Try this :


Oh yea, I always use TSP to clean grease, oil, dirt when painting. It works great and it is also a deglosser, and you do not have to rinse it off.

ok third edit. looks like its one of those days.

tsp is not what i thought it was Tri Soldium Phosphage right?). will tsp eliminate the need to sand?

Yes, TSP will take the place of sanding, unless you have flaking paint or any really ruff spots, then that must be addressed first. I’ve used it many times and it works great. I used it on the exterior of my house and it took the mold and grime off with out any hard scrubbing, then I hit it a second time to make sure it was deglossed. I was told about it by a painter. Also the painter in that forum said that he has been a painter for 25 yrs and has done hundreds of cabinets.

And yes, you can buy it at Lowes, Home depot, I have bought it at Walmart. It is green with TSP in big letters, you can’t miss it.

Good luck, Weldon

If you want to make sure you get it good you can use steel wool and a tooth brush for the deeper cracks with the tsp, then follow up with oil base kilz. The oil based primer will stick to about any thing including glass. Just make sure you cover any thing that you do not want messed up, tsp can stain wood finishes and leave floors spotty. You can also mix it with bleach to kill mold.


my house is living proof that you need to do this as the boneheads that painted (right before I bought the house) did not prep the polyurtehene and now I’m have to strip all the baseboards and doors/windows casing :stuck_out_tongue: and repaint. A clear case of “do it right the first time”…

I’ve purchased a few homes that had paneling in them that was in good shape. In order to paint over that, I used a primer called GRIPPER. It’s latex based, cleans up easy and paint sticks to it like glue. I never sanded any of the paneling and never had a problem. Try it on a small area.

I’ve done a lot of woodwork, and although I haven’t heard of the TSP stuff, I’m digging into a rehab that I will probably give it a try. As for the sandpaper, I don’t think you need to go all the way to the wood but you will want a courser sandpaper. The wood has pores to hold the finish, the rougher sand paper will provide scatches for the paint and also not clog up as much as your 220 grit. Also agree with the oil base paint if you’re positive that it is an oil base poly. Older cabinets are probably oil based poly, if you can smudge or remove finish with mineral spirits or paint thinner, it is oil base. Use oil base primer over oil base poly.

You are making this way to hard.
Get a course sanding sponge and just go over as fast as if you were just wipeing it with a rag. This will just scratch & clean it a little. Use a broom or dry brush to just get off any loose dust.
Next one coat of any latex stain killer primer like kiltz brand blue label, just need a light coat not looking to hide much. Next caulk any cracks that show up. Can see better with the white primer. Most often not but if you see anything bleed thru this primer which could be a grease spot or whatever, then switch to a shelac based primer. The kiltz brand red label to just touchup these areas. Paint with a top grade paint of your choice.

Since you have a number of suggestions and you still think it needs more than this then just try this method on a couple of feet and anyother way, let it dry a day or two and try to sand or scrape off a little area. You will be able to tell if the longer methed is worth the time.

Yes, I agree. There are a hundred different ways to do any job, the key is to find one that is best for you. Try a couple of different methods and go with the one that is easiest and does the job properly. Good luck.