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Thread: Poly is not drying!!!

  1. #1
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    Poly is not drying!!!

    I put a coat of BLO on a piece of cherry and let it dry for a couple of days, then I put on some poly and it doesn't want to dry all the way. I have sanded it off, cleaned the piece with mineral spirits, and re-coated again with poly, but still no luck. I then put on some paint & varnish remover...cleaned up the piece and tried starting all over again...but without using the BLO...just went with the poly......and still no luck. It is still sticky after a couple of days. What do I do? Any help would be appreciated. Thanks.
    "We old folks have to find our cushions and pillows in our tankards.
    Strong beer is the milk of the old."

    -- Martin Luther, Roman Catholic Priest, lived 1483-1546 A.D.

  2. #2
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    Does your poly dry when applied to a test piece ??? You DID try it on a test piece, didn't you ??? Is your poly spirits based or water base ???

    Normally, I'd be the first in line to blame the linseed oil .. I HATE the stuff. You're trying to basically apply paint to an oil that may or may not EVER dry. It's a crapshoot at best, and, well you now can see what's the worst case scenario. Your description and situation leads me to believe your poly just might be the culprit in this case.

  3. #3
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    I'm with you, Bob. Everyone seems to love BLO except you and me. Anyway, I'm guessing the OP's poly is old, or was can that was half full and stored for many months with air in the can, and is the source of the problem, as you also suggested.

  4. #4
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    I simply can't stand even the thought of putting linseed oil on anything worthwhile. It has so many drawbacks, and does absolutely nothing that can't be accomplished by more sane & predictable methods. Our great grandparents used it because it's all they had ... our grandparents got away from it as technology gave us varnishes and improvements through modern chemistry .. our parents slathered it on rake handles & outdoor stuff for protection from the elements, which was a great use of the stuff because it never really dried .. it just kind of soaked in and dissipated .. now, all of a sudden, there is this fanatic resurgence in the use of the stuff for no apparent reason. I have worked on antiques finished with linseed oil, and, after stripping off the top coats of finish, I let the pieces sit in a sunny spot in the shop ... several hours later, linseed oil was exuding from the pores of the wood. Now, if this stuff doesn't really dry/cure/polymerize/morph/whatever in 70+ years .. it ain't never going to dry. It offers zero protection .. doesn't build at all .. feeds mold & mildew .. blotches some woods on contact .. smells horrible .. and will burn your house down given the chance. What, EXACTLY does it do FOR YOU that makes it worth using in spite of all of it's drawbacks ???

  5. #5
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    Did you use raw linseed oil? When you say a coat of BLO how did you apply it? If one is to use a drying oil to pop the grain; it is best if it's allowed to soak in for a while (20 min) and then it should be wiped DRY.

    If you left a film or didn't wipe it dry, then all bets are off. If I'm using a varnish I don't usually use an oil. I like blonde or garnet shellac to pop the grain. I use BLO in home made oil/varnish blends seldom on anything else.

    Bob, seems we agree on the smell of BLO. Do you have the same opinion of pure tung oil for popping the grain? I do.
    Scott

    Finishing is an 'Art & a Science'. Actually, it is a process. You must understand the properties and tendencies of the finish you are using. You must know the proper steps and techniques, then you must execute them properly.

  6. #6
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    I can't say I've ever tried REAL/PURE TUNG OIL ... all I've ever read or heard about it suggested that it wasn't worth the time & effort to use it, so I never bothered. I have a strong preference for various concoctions of shellacs/dyes/blotch control products that enable me to enhance or pop the grain, while still minimizing or eliminating blotching. It is sometimes a fine line between controlling blotching and sacrificing some pretty grain ... I will try for the zero blotch every time ... I'd rather lose some of the desirable grain than have the dark, ugly splotches. Now, I can see where they used to use lots of linseed oil and white lead in most paints as a base, unfortunately the lead kills people, but it made a great paint base. And, one of the reasons was that while the paint skinned over, the oil in the mixture soaked in below the surface and prevented moisture migration. Unfortunately, this meant that the substrate couldn't breathe or transfer water vapor, which resulted in huge alligatoring & cracks. One look at an old house that has many coats of paint will show that condition. I guess my point is that finishes and finishing have come a LONG way through chemistry and new innovations involving modern resins & such, so why do so many people continue to return to the old ways of doing things ??? If they were so good, they would have never fallen out of favor in the first place. Practically every day you read a post or two about how someone used linseed oil in some magic concoction, and now they're having trouble with the finishing of the project. I just don't understand what they are trying to accomplish that can't be done with more predictable and desirable materials/methods.

  7. #7
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    Thanks so much, guys. Yes, I used BLO to help "pop-the-grain" in that cherry piece. At the same time I also used it on two other pieces I was finishing....one black walnut, and one piece of mesquite. Both of those two turned out fine. I was using old (maybe 30 years old) raw BLO my Dad gave me, and the poly was new, oil-based poly. I will continue to try and get that BLO off the cherry piece, either with paint/varnish remover and/or with some other concoction like acetone, denatured alcohol, lacquer thinner or some other substance that you guys can recommend. Bob and Scott, thanks for your comments and advice. I have used original Tung oil only once and will never use it again. Maybe I should do the same with the BLO. Your comments about popping-the-grain using shellac interests me. Can you give me some more details....types, methods, etc. Thanks.

  8. #8
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    Someone has probably done research on this, but I would guess that making the grain "pop" is related to the refractive index of finishing materials in and on the wood. Finishes will have different refractive indices (yes, indices, not indexes), so they will have different effects on bringing out the grain. On top of this there is clarity and surface roughness (degree of polish). These factors, and probably some others, all go into what the wood looks like through the various stages of the finishing process. In my experience, I can't say that I ever have seen the final appearance look better because I put on some type of oil under the topcoat. Of course it instantly looks great if you slather on some oil, just like wiping the wood with water or mineral spirits temporarily will. But when it's all done, a wiping varnish, shellac or shellac + topcoat, or lacquer finish looks just as good to me as oil + topcoats. And they dry predictably and in a short period of time. No BLO in my finishing room. Just my 2 cents.
    Last edited by John TenEyck; 05-25-2011 at 2:15 PM.

  9. #9
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    Just to bring this back around. The thing to check is the varnish. If it is old--particularly if it was first opened some time ago it is almost certainly the culprit. Test it on a different piece of wood.

  10. #10
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    I can only tell you what I routinely do:

    First, I write the date of purchase on the outside of every container of stuff I buy. I don't have a hard-and-fast "toss it" date, but I'm pretty agressive [conservative?] on using new stuff. Next - one of my favorite finishing sequences is just enough BLO to wet/dampen a cloth, and wipe/rub it into the surface - just the minimum to see the applicaiton.

    Come back in a couple hours, and then pad on a light cut of very pale shellac [made from flakes, no older than a couple months], and then come back tomorrow morning and go to town with the finish.

    Yes, I have even used poly - for example, wipe-on poly for walnut and QS sycamore blanket chests for young nieces [anticipating routine casual abuse] - but I always buy a new can of that stuff for any project - too much time and grief in the work to roll the dice on a qt of poly that costs a few bucks.
    When I started woodworking, I didn't know squat. I have progressed in 30 years - now I do know squat.

  11. #11
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    Thanks, John and Steve, for your remarks. Steve.....I used the same poly, (from the same can, which was a small can opened maybe a month ago...and not much missing from it) on the other two pieces and they turned out fine. So I don't think it was the condition of the poly. Since this affect only happened on the "cherry" piece, I was thinking that maybe there is/was something in the cherry that is not present in either black walnut or mesquite. But, I will continue to keep trying and getting that piece cleaned so I can put on a good, tough finish that I was intending for it. I am also thinking of using a "heat-gun" to assist in the drying, after I apply and wipe on the various products, in order to get that piece ready to accept a good finish. I think I am done using BLO on anything other than shovel/rake handles and splitting maul/axe handles (HA). John....I'm going to be looking in the future for those "refractive indices"....probably on some test pieces before I proceed with a particular finishing process. All you guys are great.....
    "We old folks have to find our cushions and pillows in our tankards.
    Strong beer is the milk of the old."

    -- Martin Luther, Roman Catholic Priest, lived 1483-1546 A.D.

  12. #12
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    I'm a bit confused. You stated that you used raw BLO. Linseed oil is either raw or boiled. It can't be both. If it's raw linseed oil, that will give you some problems. Also, the fact that it's nearly as old as I am can't help things.
    I agree with Scott, though. Their is no need to use BLO if you are going to use poly or varnish. It's a bit redundant.

  13. #13
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    Ya' know .. after digesting this a bit more .. the only thing that seems to have changed is time. I doubt the 30 year-old linseed oil went bad in a few months, nor did the poly (probably) go bad. The weather has changed significantly, however. IF you used too much linseed oil (HA .. ANY amount is too much to me), and didn't give it enough time to dissipate into the wood, AND the temperature warmed up ... it is POSSIBLE that the excess oil is migrating to the surface. It will always move from a cooler zone to a warmer one. No guarantees here, but before giving up and stripping everything, I would wash the piece down with several clean rags soaked in acetone or lacquer thinner to wash the oil from the surface. Then, seal the surface with some shellac, followed by your poly. This is pretty much the normal procedure for gluing up oily exotics (the washing part - not the shellac), and it just might get you out of a jam.

  14. #14
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    Thanks, Bob. Then that will be my next step for sure. And to Casey.....yes, I misspoke, or miss-keyed, when I wrote "raw" BLO. What I meant to write was that it was an old original formula of BLO....not some of that new stuff that is made today that says it is linseed oil, but rather a concoction of other oils and probably poly.

    And to Kent....thanks for the tip on dating your purchases. Makes a lot of sense.

    I don't care what your wives say....you guys are really good.
    "We old folks have to find our cushions and pillows in our tankards.
    Strong beer is the milk of the old."

    -- Martin Luther, Roman Catholic Priest, lived 1483-1546 A.D.

  15. #15
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    I also vote that the poly is your problem. How old is it? How was it stored? And all those sorts of questions come to mind. I don't have the problem with BLO that Bob and John seem to. I don't use it all the time but, I do use it as one way to pop grain. Flood the surface, go have a cup of coffee, wipe it off as if you've changed your mind and let it cure for a couple days to a week or so depending on climate/environment. Then finish as you please; I've never had BLO fail to cure but, I live where we only get to see weather in the movies so my experience is hadicapped by that.
    "A hen is only an egg's way of making another egg".


    – Samuel Butler

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