BS: A woodworker's minor delimna

Subject: BS: A woodworker's minor delimna
From: frogprince
Date: 28 Nov 06 - 05:06 PM

I'm not a master woodworker, but by now I've made a few furniture and decor pieces, and a little actual art, that I'm not ashamed of. However:

I give the latest doodad a coat of polyurethane. I pour mineral spirits in a can. I slosh, and squish, the brush in the can quite a bit. I wipe it on a rag. I empty the can, refill it, and repeat the same. The next time I pick up the brush, it's kind of a thick scraper. What am I missing? do I have to wash it for at least half an hour, or use six batches of fresh cleaner, or what?

Subject: RE: BS: A woodworker's minor delimna
From: bobad
Date: 28 Nov 06 - 05:09 PM

I usually wash my brushes in warm water with detergent and rinse after the mineral spirits. Have many that are at least 15 years old.

Subject: RE: BS: A woodworker's minor delimna
From: McGrath of Harlow
Date: 28 Nov 06 - 05:25 PM

I think the same rules would apply as with paint. If you are going to get back to the job soon, within the next day or so, the easy way is to put the brush in a plastic bag and tie it tightly, and you shold be alright.

If it's going to be longer, stick it in a jar with the bristles entirely submerged in some appropriate solvent - it should say on the tin or bottle what that would be.

If it's water soluble stuff you are using (which it won't be with polyurethane), the thing to do is wash the brush well in warm water, with some soap or washing up liquid, till it's clean. Then it'd do no harm to submerge in a jar full of water, to stop it drying out.

Subject: RE: BS: A woodworker's minor delimna
From: Liz the Squeak
Date: 28 Nov 06 - 05:33 PM

I've always washed the brushes well in the spirit (white spirit, turpentine, whatever) by squishing them up and down and against the side of the can until they are clean. I then wash them out thoroughly in a large amount of washing up detergent and warm water. Stand or hang them bristles downwards somewhere warm where they'll dry and be fresh for the next morning. I can make a paintbrush last over 10 years that way but it can take the bristles out if you're too enthusiastic with the squishing. It's easier with paint because you can see when it's becoming clean but varnish is difficult. You have to use your judgement.

LTS

Subject: RE: BS: A woodworker's minor delimna
From: pdq
Date: 28 Nov 06 - 05:53 PM

There are both oil-based and water-based polyeurethanes.

Also, there are two types of brushes: natural and synthetic. The latter is much cheaper, being essentially a plastic. It is used with water-based paints.

Read lables to be sure you have the right finish for the brush. What you describe could be from using mineral spirits to remove water-based finish.

Subject: RE: BS: A woodworker's minor delimna
From: frogprince
Date: 28 Nov 06 - 05:59 PM

It's oil-base poly that has been giving me the pain; I am just "sophisticated" enough to be aware of which I'm using. I haven't really been having a problem when I've used water based.

Subject: RE: BS: A woodworker's minor delimna
From: Bee
Date: 28 Nov 06 - 06:11 PM

I've been more successful with turps when using oil base poly. But there are commercial brush cleaning goos out there which work really well, even on dried brushes.

Subject: RE: BS: A woodworker's minor delimna
From: pdq
Date: 28 Nov 06 - 06:16 PM

Next step: make sure that the brush is natural ("boar bristle"). Quality ones are quite expensive.

After that, re-read lable to be sure that the thinner is exactly what the manufacturer recomends.

Step three: buy finish from a different company, as what you are buying may be stale or of poor quality.

Subject: RE: BS: A woodworker's minor delimna
From: MaineDog
Date: 28 Nov 06 - 06:33 PM

There are several products called brush cleaners and restorers that work very well, even on hardened brushes. Follow up with detergtent Ajax dish detergent and water. The brushes will be like new. The cleaning solvent can be reused many times.
MD

Subject: RE: BS: A woodworker's minor delimna
From: Geoff the Duck
Date: 28 Nov 06 - 06:55 PM

Buy cheap brushes and Bin them when they are done. It is better for the ozone layer than using excess volatile organic solvents. (Recycling is bad for the environment because it is based on Accountancy not Ecology).
Wrapping a poly bag round and fixing with an elastic band will keep a brush useable for maybe a week.
Quack!
GtD.

Subject: RE: BS: A woodworker's minor delimna
From: frogprince
Date: 28 Nov 06 - 06:57 PM

Thanks, all; I guess I've held back, probably for no good reason, from using the heavy-duty cleaners for hardened brushes.

Subject: RE: BS: A woodworker's minor delimna
From: EBarnacle
Date: 29 Nov 06 - 12:39 PM

You problem was the polyurethane, not the solvent. Unless you get a specific thinner, as recommended by the manufacturer, you are likely to be wasting your time, as the stuff has a high level of VOC's and, as you discovered, sets up like a rock. It makes a wonderful bulletproof surface but to call this stuff varnish is a misnomer. All it has in common with varnish is that it is a slightly amber, transparent surface that can be applied with a brush. Once you get a real varnish, get a real brush, china bristle for preference.

By the way, a paper mask will not do squat for you. Use an industrial face mask. If you must use that nasty stuff, work outdoors. Even so, the VOC's are likely to kill a few brain cells.

If you varnish, go for the high tung oil types, which are easier to touch up or refinish. If properly applied, they will outlast you.