Any way to save brush hardened with poly?


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Old 07-24-15, 03:40 PM
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Any way to save brush hardened with poly?

I have a brush that is hard with poly. Will thinner save it or should I trash it?
 
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Old 07-24-15, 03:58 PM
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I'd trash it, MEK or lacquer thinner might soften it up but it won't ever be a great brush again.

How long did the poly dry? if it's only been a few hours thinner might help.
 
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Old 07-24-15, 09:34 PM
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2 days... it's been sitting in paint thinner for hours now and still hard as a rock.
 
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Old 07-25-15, 01:13 AM
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Paint thinner (mineral spirits) is not a very aggressive solvent so I doubt it will ever soften the poly. I have been able to resurrect brushes with hardened oil-based paints by suspending them in a covered can with acetone, MEK or other strong solvent for a few weeks to a few months but in your case I think you are SOL.
 
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Old 07-25-15, 03:33 AM
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Mineral spirits won't touch it if the poly had dried on the brush for 2 days. A hot solvent might loosen it up but I'm not sure the end result would be worth the effort. If it's a synthetic bristle brush the solvent needed to soften the poly would melt the bristles.
 
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Old 07-25-15, 04:43 AM
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Good brushes are often worth the effort, IMO, to save them once they have set for far too long. I have used several brands of paint stripper and although I don't recall cleaning up one with poly I grabbed the last can I bought and checked the label. It does list polyurethane. I can't say how the brush will survive, but this is a brush on stripper.

My last cleaning job was a 7' AL plank for my staging that I got cheap because it was such a mess with years of paint. One can and several hours later and it was good as new.

I still have several brushes from the mid 70's. I'm not a painter by trade but they have had some use and I do get attached to them.

Note, this stuff is nasty with "poison" right on the front so use and dispose of carefully.

Bud
 
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Old 07-25-15, 07:02 AM
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Buy a can of "brush cleaner". (yes, that's what it is called) It's sold in the same section of the store as the paint thinner, lacquer thinner, denatured alcohol, etc. Let it sit in the cleaner, completely immersed, for a day or so. Then see if it has softened up the bristles. You will also want to comb it with a wire brush.

As mentioned, depending on what the bristles are made of, it may be toast, or it may not. After cleaning, I will generally let the cleaner sit for a few days to let the sediment settle, then will pour off the "clean" solvent back into the can.

If the brush cleaner costs more than the brush, it doesn't make much sense to clean it, unless its just the principle of the thing. I have a bad habit of leaving brushes laying around when I finish staining and painting, so I use the stuff pretty frequently, which makes it worth it.
 
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Old 07-25-15, 08:27 AM
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In the future if you are just looking to store the brush in between coats, place it in a ziploc bag and store in the freezer. Then when completed give it a good cleaning with the recommended solvent.

After removing poly wash with soap, water, and a hint of fabric softener if it has natural bristles. But as someone else pointed out, if you are just talk I ng about a $3 brush it may be best to cut your loss and toss it
 
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Old 07-25-15, 11:24 AM
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I've only used it a few times but the 'brush cleaner' is strong, strong enough that it will likely destroy synthetic bristles, works ok with natural bristles.

Just wrapping a brush or roller tightly in plastic will keep it overnight although setting a wrapped brush used in oil base paint in the fridge/freezer will keep it for days. Obviously you don't want to freeze a brush with latex paint.

After cleaning, I will generally let the cleaner sit for a few days to let the sediment settle, then will pour off the "clean" solvent back into the can.
I've routinely done that over the years with various thinners although I generally store it in an old can instead of mixing it back in with the new.
 
 

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