Removing old finish.

[Bugle]

My elderly neighbor has asked me to refinish two oak rockers that sit on her screened porch. I don't know what the old finish is, but I suspect it is polyurethane. It's pretty weathered and has some ugly black spots.

Other than sanding (which I absolutely abhor:no, what is the best way to remove the old finish? Also what would you recommend for the new finish? I was thinking of spar varnish since it will be exposed to the weather although not in the sun.

Thanks in advance.

 

[Gofor]

I have had good luck with a card scraper. Still some work but much better than sanding (IMHO).

As for finish, I have tried Gneral's Outdoor oil, but it does not stop the mildew (black spots) after a year or so, so I would not recommend it. Haven't found a good one yet myself.

Go

 

[DaveO]

You might try a chemical paint stripper. I have never used any on a poly finish, but I have had good luck removing old paint with them. Much less elbow grease than sanding or scraping.


Dave

 

[bluedawg76]

i'll 2nd the chemical stripper. there are formulations that are supposedly green and can be cleaned up with water (assuming that won't damage the piece). otherwise the std chem. strippers, rinsing with mineral spirits, etc is probably a much easier way to go. Just let the chemicals do the work! Card scrapers will also work much quicker than sandpaper, which i'd only use as a last resort. the other issue with physical vs. chemical, is if there's any type of stain, it's real easy to scrape/ sand through some of that stain and be forced to bring the whole piece to bare unstained wood.


Sam

 

[Bas]

+3 on a chemical stripper. Sandpaper and scrapers to get the bulk of the material off, stripper to get all the stuff in the nooks and crannies. No finish will really stand up to the elements indefinitely, but a spar varnish is probably your best bet. I don't have much experience with spar varnishes on furniture, but I've finished some wooden railings on a boat once. For the best protection, get a marine varnish. It's expensive, but it will outlast everything else.

 

[Mike Camp]

Definitely a chemical stripper. I would scrape it a little first and test the finish for lead, just to be safe. Home Depot and Lowes sell test kits. If it has lead in the finish I wouldn't touch it with a ten foot pole.

 

[Howard Acheson]

A chemical stripper containing methylene chloride is the fasted and most complete remover of any prior finish. It's virtually required for removing poly varnish. The deep pores in oak requires an aggressive stripper to get all the prior finish out of the pores.

The black marks are probably water stains caused by the failed finish. Once the finish is removed, you can use oxalic acid bleach to remove the black marks.

When recoating, avoid any poly varnish. The UV in sunlight attacks polyurethane cause rather quick failure. The finish will turn cloudy and then begin to crack and peel. Use a real marine varnish from a marine supply store. Look for brands like Wolsey, Interlux, Pettit or, best of all, Epifanes.

 

[ehpoole]

Definitely a chemical stripper. I would scrape it a little first and test the finish for lead, just to be safe. Home Depot and Lowes sell test kits. If it has lead in the finish I wouldn't touch it with a ten foot pole.

To the best of my knowledge lead was used as an opaquing pigment in paint finishes. If this is a clear coat finish (poly, varnish, etc.) over bare wood then one would not expect to find any appreciable lead content.

OTOH, if these are painted rockers more than about 35-40 years old, then lead would be of concern and spot testing would be warranted.

 

[Jeff]

Here's an environmentally friendly and safer alternative to the standard methylene chloride/solvent based strippers that the BORGs offer. It works on both horizontal and vertical surfaces so it may be a good fit for your project.

http://www.ecosafetyproducts.com/Soy-PolyStripper-Polyurethane-Stripper-p/ste-4010-1.htm

http://www.ecosafetyproducts.com/v/vspfiles/assets/images/soy-it.polystripper.pdf

+2 on Howard's recommendation to use a high quality marine spar varnish. Epifanes is the gold standard IMHO, but you pay for what you get!

http://www.jamestowndistributors.co...id=92&familyName=Epifanes+Gloss+Clear+Varnish

Good luck and let us know how the project turns out; with WIP pics of course!

 

[Howard Acheson]

Jeff, I have never found any of the "safer" or "greener" paint removers to be anywhere near as fast, effective and complete as a paint remover containing methylene chloride. The last I tried one of them it took thee applications and a total of over 12 hours to remove and oil based poly varnish that could have been done in 30-60 minutes with a chemical stripper containing MC. But, I've never tried the one you suggested, so maybe it works better.

 

[Bugle]

This is what the chairs look like:

After applying 2 coats of stripper (with methylene chloride), I am down to a layer of paint! :BangHead:

It looks as though someone "antiqued" it...remember that craze back in the '70's? I think I'm giving up on the stripper. Breaking out the ROS, detail sander, Dremel, and elbow grease. Good thing my neighbor is such a nice lady.:wsmile:

 

[Howard Acheson]

You can certainly attempt to sand off the residual finish. But, the deep pores in white oak will cause sanding to leave residual finish. This residual finish will impair any attempt to stain prior to clear coating. You are likely to end up with an uneven coloring.

I am surprised that your paint stripper did not do a better job. Paint strippers containing methylene chloride will easily remove any one part finish from prior to the 1990's. The only exception is a milk paint.

 

[Jeff]

Howard,

I understand your point. I have no personal experience with the newer "green" stripper that I posted above. Although it's soy based it also contains about 20% N-methyl pyrrolidone which is supposed to be effective as a general stripper, but slower than methylene chloride. :icon_scra

Preston,

The chair is looking better so carry on. I've read that a brass bristle brush can be helpful. Put on the stripper and brush away for cleaning up the residue in your pic #2. :icon_thum

 

[Glennbear]

Howard,

I understand your point. I have no personal experience with the newer "green" stripper that I posted above. Although it's soy based it also contains about 20% N-methyl pyrrolidone which is supposed to be effective as a general stripper, but slower than methylene chloride. :icon_scra

Preston,

The chair is looking better so carry on. I've read that a brass bristle brush can be helpful. Put on the stripper and brush away for cleaning up the residue in your pic #2. :icon_thum

#1 For the brass bristle brush, I found them quite helpful when stripping paint off kitchen cabinet doors using Methylene Chloride stripper. :wsmile:

 

[Bugle]

I think the problem is solved. My neighbor bought a new glider for her porch. It's black and she wants the chairs to match so I'm painting them with a high gloss oil based paint. Gonna save me a lot of time.