Removing varnish/lacquer/poly

[Victor Robinson]

I'm trying to salvage some hardwood from furniture a friend was trashing. It was finished with what I would guess to be varnish, but there's an off chance it could be poly. What's the most efficient way to get it off? Too hard on planer knives? What about 36grit on the drum sander?

[Jim Matthews]

This is not something you want in the air.
The polymerized finish is extremely sticky and may adversely affect your lungs.

That, and the dust will settle in your house for months. (Like sanding drywall.)

I recommend a carbide paint scraper until you're down to the wood.
Some finishes can be softened with infrared radiation (http://www.silentpaintremover.com/scrapers/scrapers.htm) (heat).

[John Coloccia]

Use paint stripper.

[Dustin Keys]

I would start with trying a simple solvent to see if you get lucky. If that doesn't phase it and you think it's some sort of poly, I would use a heat gun and paint scraper to melt and peel it away.

D

[Prashun Patel]

If your pieces are few and flat, then it might be easiest to use a card scraper to remove the bulk of the finish and then use the planer to make it smooth and flat.

Strippers are great, but they are among the most aggressive chemicals that you'll use, and they can be messy.

Strippers might also be appropriate if you have a lot of curved work or if you are planning to refinish and wish not to mar the wood at all.

But if you are 'reclaiming' the lumber alternate use, then a card scraper - for that matter a hand plane - can be quite effective at removing the finish layer without a lot of dust or slop. They're also easier to resharpen than your planer knives.

[Ben Hatcher]

Having used a card scraper to remove finish from a large table top, I can tell you that they are murder on your hands. A proper paint scraper is MUCH easier to use, especially if you get one with a second handle over the knife.

[Dustin Keys]

Correction: I said paint scraper, but I meant putty knife. A heat gun and putty knife does the safest and most efficient job I've seen of removing poly.

D

[Victor Robinson]

Thanks fellas - didn't even think of stripper. Tried a "safe" type and it got enough off to a point where I wouldn't mind running the wood through the planer.

[Prashun Patel]

Others have said the same thing, Ben. I removed spar varnish from a slatted outdoor bench 2 years ago, and the card scraper was not difficult at all. Just my experience. Also, the goal isn't to get ALL the finish off, just the 95% so it can be planed with minimal negative effect on the cutters.

[Stephen Cherry]

The card scraper would be the first thing to try for me also. I've used it on varnish, and what I think was lacquer, and if the finish is in poor condition, it will basically zip right off. You need to sharpen frequently, and if the finish is in good condition it may not scrape very easily.

[Carl Beckett]

I have one of those paint scrapers with a second handle over the blade (carbide inserts as the cutting edge). I have to say, it makes a pretty good scraper, and can even make shavings when smoothing wood. Better than a traditional card scraper for something like finish removing (or glue, etc). For me that is.