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Thoughts On Using Xylene/xylol As Varnish Thinner & Brush Cleaner

Discussion in 'Wood and Canvas' started by Howie, Jan 18, 2019.

  1. Howie

    Howie Wooden Canoe Maniac

    Has anyone out there used Xylene/Xylol instead of paint thinner or mineral spirits?

    I used to clean foam brushes with paint thinner after varnishing, with the thought that I could reuse brushes. But I noticed that a thick waxy goop built up on the brush if left in the thinner/varnish solution for a few days. Switching to mineral spirits improved the situation, but there was still 'wax' on the brush after a while.

    I then tried Xylene/Xylol. Wow - what a difference. No waxy goop at all even when I leave the brush in the thinner/varnish solution for a few weeks!

    So now I use Xylene/Xylol to thin varnish as well and have noticed no problems. Does anyone see a problem with Xylene/Xylol?

    And I've just tried this: I have a half empty can of varnish that I know will develop a 'skin' by the time I need to use it. So I've just poured maybe 1/4" of Xylene/Xylol in the can and didn't stir it. I'm thinking that the thin layer of Xylene/Xylol will act as a barrier between the varnish and air in the can which should prevent skin formation & thereby extend the life of the varnish. Thoughts?
  2. Michael Grace

    Michael Grace Lifetime Member

    Hi Howie,

    I believe xylene and xylol are two names for the same thing, more properly called xylenes because it's a mixture of 3 chemically distinct but nearly identical structures based on a 6-carbon ring, all three called dimethylbenzene. That said, it's chemically much simpler than mineral spirits, naphtha and other complex petroleum-derived solvents that contain a variety of straight-chain hydrocarbons and simple ring structures. The simplicity and structural stability of xylenes probably account for the success you've had with it, rather than the goop on brushes that comes after leaving a brush in paint thinner.

    All organic solvents should be used with care. Xylenes can cause central nervous system depression in the short term and long-term nervous system depression following repeated exposure. And it quickly strips your skin (and other tissues) of oils, so it can be a potent irritant. And it's highly flammable.

    [I've used xylenes for decades in lab work with no apparent ill effects. In fact it's cleared things up for me - now I can see the flying monkeys almost all the time...]

    If you want to read about the potential health effects, try this:

    As an aside, toluene is a close relative and its health risks are similar to those of xylenes. On the other hand, the chemical relative benzene is very dangerous, causing a variety of very serious short term health effects including death, and long-term health effects including leukemia. Take care when using any organic solvents.
    Last edited: Jan 18, 2019
  3. dtdcanoes

    dtdcanoes LOVES Wooden Canoes

    And then......there are Black Holes, too ! I don't get this..please, dunk the brush many times........spin the bugger mechanically or by hand with rubber gloves on and hang 'er to dry. I have two Epifanes oval brushes that I have used for twenty years and they are not done yet. And , yes I let the thinner settle in the gallon jugs ( I have two at work...1 for varnish etc.). I do flick my brushes a lot before use with a lot of Vivaldi ( Italian, as are the brushes ) When the jugs have an inch or so of sludge in the bottom, I find a new jug.
  4. Michael Grace

    Michael Grace Lifetime Member

    Dave makes an excellent point. I got distracted by my interest in chemistry, but the simple answer is... clean the brush, remove as much of the solvent as possible, and store it so that it can't collect dust. Brushes not left in the solvent won't get gooped-up. And there's another reason to clean and store them out of solvent: long-term exposure to solvents can loosen the bristles in some brushes, ruining them. Like Dave, I've got brushes that are decades old and I still use them with great results. I clean them, comb them if needed, spin out the thinner, and wrap them in lint- and dust-free material before storing them in a dust-free environment. And I also let used thinner settle, and then decant off the upper clear stuff to use again.
  5. Dan Lindberg

    Dan Lindberg Ex Wood Hoarder


    Are you talking about cleaning FOAM brushes or BRISTLE brushes,
    if foam, the whole point of using them is to throw them away after single use.
    If bristle, Dave and Michael covered it.

    Maintaining varnish in the can is another subject.
    I'm not sure I'd use the Xylene like you did, but maybe the thinner recommended by the varnish manufacturer.
    I happen to favor Interlux so for me that would be the 333 brushing liquid.

  6. OP

    Howie Wooden Canoe Maniac

    Micheal - Thanks for the chemical info.
    And everyone; thanks for the comments on cleaning the brushes. Yeah, I know foam, brushes are meant to be disposable. But what disturbs me is the goop that develops when cleaning with mineral spirits & paint thinner. Makes me think that something bad is happening inside the varnish... though the goop does take time to develop so certainly a varnish layer would have dried by then. But it might indicate that one should never keep leftover varnish which was thinned with these thinners.
  7. mccloud

    mccloud "Tiger Rag" back on the tidal Potomac In Memoriam

    Howie, Are you talking about a goop buildup in brushes following use of a latex paint? If the label says clean with hot water and soap, then that's latex, and there will be a waxy sort of residue on the bristle following cleaning. I keep a container of Goop waterless hand cleaner above the sink, and after washing with water, massage the hand cleaner into the brush and then wash that out. It seems to help.

    When it comes to a chemistry lesson regarding solvents, that can quickly get rather involved, but let me simplify: solvents are categorized into groups depending on the similarities of their physical properties - we won't go there. But everyone knows that oil and water don't mix, nor do vinegar and oil salad dressings. Oils are at the extreme non-polar end of the chemical spectrum while vinegar / water are at the extreme polar end. Those solvents which are most alike and have similar physical properties will mix with eachother, like mineral spirit, turpentine, gasoline, oils, kerosene, xylene, toluene, etc. which will mix with an oil-based paint are at the non-polar end. Water, methanol, ethanol, as you would use for shellac are at the polar end. Solvents that have intermediate polarities such as acetone, ethyl acetate, methyl ethyl ketone are often good diluents and a good choice for cleanup because they will mix to a certain extent with both polar and non-polar. If you need more details, PM me, or else read articles in the scientific literature by Lloyd Snyder. I have yet to figure out a good solvent combination to add to spar varnish that will prevent a skin or precipitate from forming over time. Tom McCloud
  8. OP

    Howie Wooden Canoe Maniac

    Tom - O no... I know Latex is water soluble.
  9. Greg Nolan

    Greg Nolan enthusiast

    I am familiar with the goop that Howie describes. I have experienced it when I am applying a number of coats of varnish over a period of a few days. Rather than thoroughly cleaning my brush, I will give it a quick rinse with thinner (usually mineral spirits) and then place the brush, far from fully cleaned, in a small can of thinner, and cover the can with aluminum foil to keep the thinner from evaporating. I can then resume varnishing the next day after simply shaking the brush out, saving the thinner in the can for the next rinse of the brush. This works pretty well and saves thinner -- but

    If life intervenes for a few days and I cannot get back to the next coat of varnish in a timely manner, I will find a yellowish goop up near the top of the bristles, near the ferrule. I can usually clean the brush well enough with more new thinner and keep on going.

    I believe that the goop is simply varnish which has cured, notwithstanding the immersion in thinner. Varnish only partly “dries,” that is, the solvent which is part of the varnish, evaporates in a matter of an hour or three. The remaining components of the varnish then “cure” by oxidizing or otherwise chemically reacting. Because the varnish is very wet with thinner, the cured material is a wet varnish goop rather than a hard varnish coating. Thinner will not dissolve this goop (as it will uncured varnish), but if there is not too much of it, it can be simply rinsed out of the brush. If the rinsing is not done well, tiny particles of the goop will contaminate the next coat of varnished applied by that brush.

    The only way to prevent this goop is to thoroughly clean your brush right after use -- holding an uncleaned brush will usually work only overnight, or maybe for two days with luck and cool/cold temperatures.

  10. OP

    Howie Wooden Canoe Maniac

    Thanks, Greg. But your last sentence isn't true: goop doesn't seem to form when you thin with xylene. I've left a foam brush in it for 2+ weeks (as an experiment!) and the brush sill looked great. Maybe a big xylene-to-varnish ratio prevents oxidation? I can tell you that thinning varnish with just a little xylene seems to have no ill effects on the varnish - it dries just fine.

    In any case, thanks everyone for their comments. Just idle curiosity raising it's head in the dead of winter...
  11. Dan Lindberg

    Dan Lindberg Ex Wood Hoarder


    What varnish brand/model are you using?

  12. Todd Bradshaw

    Todd Bradshaw Sailmaker

    A question which always comes to mind when adding non-standard chemicals in situations like this is "Does it have any undesired effect on the UV absorbers that are in the stuff, or on whatever naturally occurring UV resistance the material came with?" I don't know the answer, but we sometimes see that happen with fabrics, where exposure to certain stain removing and cleaning solvents can dramatically reduce the UV lifespan of the synthetic cloth and the coatings applied to it.
  13. mccloud

    mccloud "Tiger Rag" back on the tidal Potomac In Memoriam

    Xylene and other solvents at the non-polar end of the polarity spectrum are rather chemically non-reactive, so I doubt there is any effect on UV-absorbing compounds. If I ran out of turpentine and needed a little diluent to thin Epifanes spar varnish, I would not hesitate to use xylene. Of course these organic solvents are all flammable, rappidly reacting with oxygen, but that is an altogether different situation.
  14. OP

    Howie Wooden Canoe Maniac

    Dan - I usually use Total Boat Gleam, but for the last one I used Epifanes.
  15. Dan Lindberg

    Dan Lindberg Ex Wood Hoarder

    Never heard of the Total Boat and have never used Epifanes.
    I guess I live a sheltered life. :)
    I tried Captain's once years ago, but didn't like it.
    Too thick and the last 1/2 of the can turned to jelly after a short time.
  16. Michael Grace

    Michael Grace Lifetime Member

    Excellent marine spar varnishes do take some getting used to if the watery hardware-store-bought versions have been used previously. I've tried almost all traditional spar varnishes; Captain's was once my favorite, but after trying Epifanes many years ago I've never looked back. Wonderful stuff. As for the gelling, the best bet is to plan varnishing so that partial cans aren't left behind, especially ones with lots of air space. Of course that's not always possible so another option, as Howie suggested, it to put something over the top of the varnish to displace air from the surface of the varnish. Howie's idea of a solvent might work (I've never tested it), or you can put in a heavier-than-air gas. Bloxygen (argon in a pressurized can) is a commercially available example of the latter:

    It's not cheap but a can goes a long way, and it's a lot cheaper than throwing out varnish that costs upwards of $35/qt.

    Regarding TotalBoat, this is Jamestown Distributors' own label, created just a couple of years ago. I haven't tried the TotalBoat varnish, but I just tested the TotalBoat Wet Edge Topside Paint, and loved it. It seemed a little thinner than some other paints, but it went on easily, flowed out well, and had good coverage. I will certainly use it again.
  17. Dave Osborn

    Dave Osborn LIFE MEMBER

    Well said, Michael.
    I’ve been a Epifanes user for several years. I’ve often stated that you could apply it with a broom and it would flow out perfectly. In actuality, probably not the case but it does attest to the flow of it when used properly. I’ve had good luck with it using both natural badger brushes and foam brushes. I tend to use badger brushes on the first coat because it lays it out thicker and will soak in more varnish. I don’t thin. I feel that out of the can the first coat is absorbed pretty well. I use foam brushes on the final coats because it applies a thinner coat. I’ve had occasional issues with “puddling” when using the badger brush on final coats.
    Funny you mention gelling..... Yesterday I opened a can 3/4 full and it was jelled on the surface. Crapola! Forgot to use the Bloxygen. That stuff works well....if you use it.

    As is common in our wooden canoe world, everyone uses different methods, likes different products, and has success in their own ways. I’ve always believed that a little extra money for three things is worth the price paid....paint stripper, varnish, and paint.
  18. pklonowski

    pklonowski Unrepentant Canoeist

  19. Todd Bradshaw

    Todd Bradshaw Sailmaker

    I have usually used Captain's Varnish and a variety of different paints, but never have problems with gelling in the can, drying out, films forming on top or anything else - and I can leave a half-filled can on the shelf literally for years. I don't add anything to the paint or in the can and when eventually re-opened, the stuff inside looks and performs exactly like it did when first used. The "trick" is a little vacuum pump gizmo my wife bought off of an infomercial about 20 years ago called a "Pump-n-Seal".

    You put the lid on the can properly and snugly, then take a map tack and punch a single pin hole in the lid. Then you stick a little Band-Aid like thing they give you over the hole. This becomes a one way valve of sorts. The pump looks like a mini bicycle pump with a suction cup on the bottom. You set it over the Band-Aid give it a few strokes with the handle and it sucks all the air out of the can. No air = no gel, no film, no change. You don't have to, but I normally then cover the Band-Aid with a piece of clear packing tape, just as a long term safety since marine paints and varnishes are so expensive and I may store them that way for years before needing them again. It's also great for saving custom mixed paint colors, so that if you ever need to touch up the paint you don't have to try to mix and match the original shade.

    Back when we bought the Pump-n-Seal it cost about $20. These days it has almost doubled, but so have the prices of marine paints and varnishes, so if it will save one can from drying out, it will still probably pay for itself. It looks kind of like your typical cheesy infomercial product, but that little sucker works!
  20. Greg Nolan

    Greg Nolan enthusiast

    I have had good results with Private Preserve, a gas mixture (nitrogen, carbon dioxide, argon) sold to keep open bottles of wine from oxidizing and going bad. Available on the internet for $8 and up. Once opened, bottles of wine don't stay around long enough in our house to warrant using it for wine -- but opened varnish sometimes stay around for quite some time in my shop.

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