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Thread: Removing hardened latex paint from brushes - what's effective?

  1. #1
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    Removing hardened latex paint from brushes - what's effective?

    These days, it probably makes more sense to throw away old paint brushes that have hardened latex paint on them - as in "I got so busy putting away the tools that I forgot to wash the brush". However, out of idle curiousity, what is the best way to clean such a brush. On the web, I find advice to soak it in warm soapy water (I don't believe that) or isopropyl alcohol (I'd probably have to buy laquer thinner to get pure isopropyl alcohol; the grocery store type of alcohol is part ethyl aclochol) or vinegar (that would suit me).

    What's really best?

  2. #2
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    I've done a lot of house painting and just renovated an office where I had to remove 3-year-old dry latex paint from painted surfaces - denatured alcohol works very well dissolving dry latex paint. It works better than acetone/ laquer thinner or "goof off" and is less volatile. HD or a hardware store should have it in the paint thinner/ chemical section - I'd let the brushes soak in it, then use a plastic hair comb to start pulling the chunks out - then soak more to loosen more if needed (it doesn't seem to penetrate too deeply, so you have to remove the softened layers for it to keep going). They sell "Latex Paint Remover" as a special product, but it smells and works just like denatured alcohol - but costs about 10 times as much.

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    Never, under any circumstances, combine a laxative and sleeping pill, on the same night

  4. #4
    I've used paint remover and it works pretty well. Pour some in a can and let the brush stand in it over night. A stiff wire brush will help get the paint out of the bristles.
    Lee Schierer - McKean, PA

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  5. #5
    Wow. Good to know about the DNR. I would have said "Goof Off" would do the job.

    I usually just throw everything in a five gallon bucket of water when I get through painting, and then use a brush comb on the hard stuff (don't stab yourself with one of these things!). Or at least wrap a wet rag around the brush if I'm in a hurry.
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  6. #6
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    On the web, I find advice to soak it in warm soapy water (I don't believe that)
    That's actually a great idea!

    If you sell brushes...

    Soaking in water will cause the wood in the handle to swell and the ferrel (the metal band) to become loose. The brush is pretty much destroyed for any serious use when that happens. It may still make a decent duster - but - as a painting tool, it's days are over.

    The "trick" to removing hardened material of any kind from a brush is to keep the bristles mostly out of the solvent and allow the fumes to work on the dried material.
    Lacquer thinner does a good job.

    Take a 2lb coffee can w/a plastic lid.
    Cut a slit like this >--------< in the lid wide enough to stick the brush through.
    Place some lacquer thinner in the can, just enough so that it just touches the bottom of the bristles when you suspend the brush by pushing it through the slit.
    Set it aside for a few days and allow the fumes to soften the dried material.

    After a few days, try running a brush comb through the bristles. Don't use a wire brush. A wire brush will put a permanent "curl" in the bristles - a lot like what happens when you pull a ribbon over a scissors blade to form a decorative bow.
    If the dried material is still too hard, stick the brush back in and give it a few more days.

    Once the material has softened enough, try cleaning as you would any other brush used in solvent based materials.
    Wash in mineral spirits, spin it with a brush spinner (Lowes and HD sell them for about $11 to $15 bucks - don't force the jaws on one and it will last you forever) and repeat as needed.
    Once the brush is clean, spin it dry then wrap it and hang it up with the bristles pointed down.
    Don't store a freshly cleaned brush on it's side. It has to hang to allow the solvent still inside to escape.

    After a week or so, remove the wrap and reclean the brush in hot soapy water, rinse well, then rewrap and hang it.

    I'm not going to kid you. It takes time for this to work. More time than most people care to devote & the chances of you forgetting about the brush hanging in the can are excellent to almost a given.
    Persoanlly, while I've done the above more times than I care to count, I won't resort to it unless the brush is one of my better 3 1/2" sash tools.
    Those are too hard to come by.

  7. #7
    I like the coffee can with a slit in the lid, but I would put paint remover in the can and after an overnight soak, washing brush in soapy water is all thats necessary. No brush combing needed.

  8. #8
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    Quote Originally Posted by Rich Engelhardt View Post
    That's actually a great idea!

    If you sell brushes...

    Soaking in water will cause the wood in the handle to swell and the ferrel (the metal band) to become loose. The brush is pretty much destroyed for any serious use when that happens. It may still make a decent duster - but - as a painting tool, it's days are over.

    The "trick" to removing hardened material of any kind from a brush is to keep the bristles mostly out of the solvent and allow the fumes to work on the dried material.
    Lacquer thinner does a good job.

    Take a 2lb coffee can w/a plastic lid.
    Cut a slit like this >--------< in the lid wide enough to stick the brush through.
    Place some lacquer thinner in the can, just enough so that it just touches the bottom of the bristles when you suspend the brush by pushing it through the slit.
    Set it aside for a few days and allow the fumes to soften the dried material.

    After a few days, try running a brush comb through the bristles. Don't use a wire brush. A wire brush will put a permanent "curl" in the bristles - a lot like what happens when you pull a ribbon over a scissors blade to form a decorative bow.
    If the dried material is still too hard, stick the brush back in and give it a few more days.

    Once the material has softened enough, try cleaning as you would any other brush used in solvent based materials.
    Wash in mineral spirits, spin it with a brush spinner (Lowes and HD sell them for about $11 to $15 bucks - don't force the jaws on one and it will last you forever) and repeat as needed.
    Once the brush is clean, spin it dry then wrap it and hang it up with the bristles pointed down.
    Don't store a freshly cleaned brush on it's side. It has to hang to allow the solvent still inside to escape.

    After a week or so, remove the wrap and reclean the brush in hot soapy water, rinse well, then rewrap and hang it.

    I'm not going to kid you. It takes time for this to work. More time than most people care to devote & the chances of you forgetting about the brush hanging in the can are excellent to almost a given.
    Persoanlly, while I've done the above more times than I care to count, I won't resort to it unless the brush is one of my better 3 1/2" sash tools.
    Those are too hard to come by.
    +10 to that Rich. My thoughts though lean towards not Allowing the brush to get in that condition. your procedure is what I saw my Dad use when needed. I cringe when I see folks use a wire brush.

    I learned the hard way at a young age by leaving a 4" china bristle standing in a can of paint and went to do teenage things. Sometimes I think I am still pulling those hog hairs out of...lol

  9. #9
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    I would put paint remover in the can
    Paint remover can be too rough on the bristles and the epoxy that binds the bristles to the handle.
    It might be ok - if you keep a real close eye on things.
    Get sidetracked and forget for a few days and there's not much left to salvage out of what used to be a brush.

    I should add also - make sure you store the can w/the slit outside or at the very least, somewhere that there aren't any open pilot lights and/or flames near ground level. The slit isn't air tight and as the lacquer thinner evaporates, the fumes will fill the can and
    "spill" over.

  10. I use 91% Isopropyl Alcohol (aka Rubbing Alcohol) to remove hardened latex paint from brushes. It is must less flamable than lacquer thinner (which can ignite explosively), cheaper, less toxic and is available at any grocery store. An overnight soak doesn't damage the brush and the alcohol won't evapore in that time. While other chemicals (paint stripper, lacquer thinner, etc.) the alcohol works extremely well without the hazards of the others. Just my 2 cents worth.

  11. #11
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    I like Rich's recommendation with the exception of the brush spinner. Maybe I'm using it wrong but in my experience a brush spinner splays out all the bristles and they are never right again - except as shaving brushes. . I prefer to slap them flat back and forth over a board edge or the like. Spinners are for rollers IMHO.
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  12. #12
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    Hi Sam,
    What you do is after you spin the brush - and while it's still damp - you wrap it in a piece of paper. Newspaper will work and so will copy (printer) paper.

    http://www.purdy.com/painting-resour...RoCpWsQAvD_BwE

    At the very end they wrap it.
    I always give a slight tug on the brush after folding the end over just to make sure I haven't folded the ends of the bristles over.
    I did that one time.....
    Every loaf of bread is a tragic tale of grains that could've become beer.......but didn't....

  13. I understand "forgetting" to clean a brush, or being in a hurry, but if you use expensive brushes, you soon learn not to forget. I have "finest sable" chisel writers that are close to $100 each. It only takes a minute to clean & oil them ....
    Brushes with hardened acrylic paints are harder to clean ...... but, IF you have access to a Sign Supply company, here a fast way to clean your brushes .....
    Rinse out the worst of the paint in water . Then, using a spray bottle of Rapid Prep ( available from most sign supply companies, ) spray the bristles with enough Rapid Prep for it to "foam up". Squeeze out the slime. Do it again if you, & give a final rinse in water..
    Mind you, I never use 3" wide brushes, but I use those "round"brushes a lot. I hold the brush so I can spray right up into the heel, & everything just "flows" out.
    IF you're painting with white acrylics ( heavy with solids) you have to clean your brush every 15 minutes or so.
    I have brushes that I use almost daily that are close to 10 years old .....

  14. #14
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    Krud Kutter.

    Works great, no fumes. Iím horrible at cleaning brushes but I never throw them away. After I have ten or so I gather them up and begin a mass soaking. Then two or three days later itís cleaning time. I donít have a spinner but I do spin in my hands inside a trash barrel. Shape the bristles by hand, wrap tightly in a paper towel sometimes with a rubber band, and let dry for at least a week or two. Good as new- adjusting for the fact that they are not new, and then they go back into their original cardboard holders.
    Given that a Purdy brush is fifteen bucks and up now, bringing them back to life makes perfect sense.

    Amazon had it as low as eight bucks a quart a few months ago - shop around.

  15. #15
    I use a brush comb with an attached brass brush. I use the brush spinner then comb it back to flat. Only realized. a few years ago that the concave portion of a stiff paint remover tool is there to clean a roller.
    Bill

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