Lots of people have observed that when using oils, particularly tung oil, the surface can appear dry without actually being dry enough to avoid screwing it up if you recoat too quickly. I'm doing some test pieces of alder and black korina with Danish oil, tru-oil, and tung oil, and want to be sure I'm leaving sufficient time for drying on each (my last experience with tung was not good because I jumped the gun on the second coat). I'm working in a basement that is dry but not especially warm. Is there a way of determining if your coats are dry beyond just waiting (which I'm happy to do)? I figured I'd give the tung coats a couple of days each at least, but the Tru and Danish oil directions make it sound like you can recoat more frequently. I've heard that dry tung oil can give off a whitish powder when sanded -- is something similar true of the other oils?
how can you be sure oil is dry enough for the next coat?
- Thread starter kdownes
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=CB= convinced me to try pure tung oil finnish, and I'm glad i tried it, the neck i finnished is like soft and smooth and glows in the dark, well no it doesnt glow.
I applied my coats of tung oil as thin as I could put it on, and for a while I wasn't sure it was building up thickness, but I assure you it does,
Thin coats allow them to dry overnight, I applied a coat a day for about 3 weeks
I applied my coats of tung oil as thin as I could put it on, and for a while I wasn't sure it was building up thickness, but I assure you it does,
Thin coats allow them to dry overnight, I applied a coat a day for about 3 weeks
silent_k said:
a - the terms Danish oil, and tung oil are very very widely varied in meaning. Some Danish oil is a varnish with oils (like linseed) in it. Other danish oil is more like a mineral spirit/naphtha solution into which waxes have been dissolved. Tung from big box suppliers is varnish or urethanes with "some tung oil in it". Pure tung oil is a totally different (and much nicer) product. We gotta know which you're using.
b - warm helps because oils polymerize with interaction to the air. The warmth will speed up the chemical reaction
c - that makes me think you're using Watco and chain store tung oil
d - pure tung, when dry, will sand to a very light colored powder
O
old_metal_head
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I have used this stuff with results better than from Minwax (Formby's):
http://www.newlifewoodconditioners.com/tung-oil/
http://www.newlifewoodconditioners.com/tung-oil/
D'oh! Should have included the brands:
Watco Danish oil
Birchwood Casey Tru-Oil
Woodcraft Pure Tung Oil
Despite my newbie-ness, I've seen enough of CB's posts to avoid the Home Depot-style tung oil!
I can warm up the basement here and there with a space heater, it's just not something I can leave on all the time when I'm not around. And we have a dehumidifier running to keep things around 60% humidity, and my guess is that it's about 65 degrees down there. The Birchwood Casey directions say you should give it at least 2 hours to dry, and the Watco directions say to let the first application soak in for 30 minutes, then apply again and let soak for 15 minutes, then it can be used in 8-10 hours (or 72 if you're planning a poly coat). I let my Danish test pieces dry for over an hour before I applied a second coat, and I haven't added any more coats to the others (it's been almost 24 hours). I cut the tung oil to 50/50 with mineral spirits.
Watco Danish oil
Birchwood Casey Tru-Oil
Woodcraft Pure Tung Oil
Despite my newbie-ness, I've seen enough of CB's posts to avoid the Home Depot-style tung oil!
I can warm up the basement here and there with a space heater, it's just not something I can leave on all the time when I'm not around. And we have a dehumidifier running to keep things around 60% humidity, and my guess is that it's about 65 degrees down there. The Birchwood Casey directions say you should give it at least 2 hours to dry, and the Watco directions say to let the first application soak in for 30 minutes, then apply again and let soak for 15 minutes, then it can be used in 8-10 hours (or 72 if you're planning a poly coat). I let my Danish test pieces dry for over an hour before I applied a second coat, and I haven't added any more coats to the others (it's been almost 24 hours). I cut the tung oil to 50/50 with mineral spirits.
AprioriMark
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I'm about to finish a couple maple necks. I would really like to clear poly the headstock and neck joint area while putting Tung oil on the neck itself. Every other day for coats of Tung? I'm assuming Poly first, but I'd appreciate advice.
-Mark
-Mark
I've just done some (more ) reading on Danish oils.... what a ball of wax (pun).
The long and short - Danish oil can be anything that mimics the finish used on "Danish teak" furniture that was popularly imported in the 50's and 60's.
It can be polymerized oil, varnish/oil mix, thinned varnish, dissolved waxes... you name it. All bets off, use at your own risk - but Watco has a good rep. It happens to be a thinned oil/varnish mix (less oil, more vanish).
True-Oil is varnish with oils and driers and such, such that it applies sort of like, and appears sort of like, an oil finish.
That 100 percent Tung, is tung oil.
As for the neck with poly and oil mix. I think I'd rather go with lacquer vs poly, and do that first, then just go carefully at the edge. Tung oil wont hurt it, but the Watco and TrueOil might.
Lacquer will buff out to a high gloss with very little work, much easier than any inexpensive poly. A 2k poly would be the alternate there.
The long and short - Danish oil can be anything that mimics the finish used on "Danish teak" furniture that was popularly imported in the 50's and 60's.
It can be polymerized oil, varnish/oil mix, thinned varnish, dissolved waxes... you name it. All bets off, use at your own risk - but Watco has a good rep. It happens to be a thinned oil/varnish mix (less oil, more vanish).
True-Oil is varnish with oils and driers and such, such that it applies sort of like, and appears sort of like, an oil finish.
That 100 percent Tung, is tung oil.
As for the neck with poly and oil mix. I think I'd rather go with lacquer vs poly, and do that first, then just go carefully at the edge. Tung oil wont hurt it, but the Watco and TrueOil might.
Lacquer will buff out to a high gloss with very little work, much easier than any inexpensive poly. A 2k poly would be the alternate there.
DangerousR6
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I did 2 Danish oil projects this year here in Texas, started early spring to mid summer. I also used Watco's brand, it was taking, on average about 2 days to be dry enough not to load up my sandpaper. But I also spent the first week wet sanding with the danish oil, alternating every other day, letting dry then wet sanding. :icon_biggrin:
I gotta say this about tung oil finishes, mine seem to feel better the older they get and the more I play em. I didn't sand anything with my tung oil finishes, just buffed it out about 2 weeks after my last coat on a stew mac buffer, The buffer really brought out the good qualities of the tung oil finnish, but in hindsight, I don't think any buffing is required, maybe just a paper towel or a rag run up and down the neck a few times woulda worked just fine
Time and Playing will be all thats needed for the tung oil neck to feel like heaven
Time and Playing will be all thats needed for the tung oil neck to feel like heaven
Keyser Soze
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In my experience true oil finishes (plain boiled linseed, and pure tung) do not build well to a heavy surface film. They are best done as 'in the wood' type finishes. These are also the finishes that can take forever to dry and have the most problem of bleeding out from the pores as they do dry. Fortunately these problems can usually be corrected by a light application of oil, and a heavy application of elbow grease. So, the simplest way to tell if a coat is dry is to feel it. Rub your fingers over it, and if it feels tacky it's not dry. Can this create a surface smudge? Sure, but you are not building a heavy surface film anyway, so apply a tiny amount of oil and then rub it out smooth. Do not be surprised as it takes progressively longer for each subsequent coat to dry - this is normal.
Danish oils are much more of a crap shoot. Mainly because they are the least 'standard' of the bunch. Some are oils and solvents, some are oils and dryers, some are oils and clay. The only way to reliably predict them is through hands on experience.
The 'varnishes' (like Tru-Oil, Lin-speed, Formby's oil finish, etc.) tend to dry fairly quickly and reliably, but again, the best way to test them for dryness is by touch. In this case use a light touch in an unobtrusive area, and if it is not dry and you create a smudge, give it more time to fully dry then scuff away the smudge prior to applying the next layer.
Danish oils are much more of a crap shoot. Mainly because they are the least 'standard' of the bunch. Some are oils and solvents, some are oils and dryers, some are oils and clay. The only way to reliably predict them is through hands on experience.
The 'varnishes' (like Tru-Oil, Lin-speed, Formby's oil finish, etc.) tend to dry fairly quickly and reliably, but again, the best way to test them for dryness is by touch. In this case use a light touch in an unobtrusive area, and if it is not dry and you create a smudge, give it more time to fully dry then scuff away the smudge prior to applying the next layer.
Keyser Soze said:
Oils dont build a finish depth, but I dunno... I'd much prefer tung than linseed on a rifle stock. To me, tung builds the better, harder, more resilient finish
Bleeding can be largely prevented with using thinned oil as the first coat, and letting it dry completely before adding any more unthinned 2nd and later coats. This cannot be stressed enough. The reason is oils air dry, and need exposure to air. Linseed and tung in a can will "skin over", air drying from the top down. Once dry, they will not reflow, and effectively seal any liquid oil from penetrating into the wood. So, first coat thin, totally dry, then proceed to other coats.
The "longer as it goes" drying means that you were too short on the first coats. Whats happening is the under coats are not dry and now have been sealed over by the new coats. Remember "dry to touch" is not dry enough. Taken to an extreme, you get "the gummies" and a really terrible finish. I had that happen on a bench that was supposed to have a linseed oil finish. It got gummy - my own fault for rushing and it took oh... 18 months to dry. Maybe two years, it was a while ago.
Keyser Soze
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All true. I'd also agree that tung tends to give a better surface build than plain boiled linseed (but that's not really saying much.) I'd also agree tung is the 'harder' of the two but the downside is that also translates to a bit of brittleness that makes tung more prone to surface damage (including routine wear) than BLO. Even when fully dry BLO is much more plastic, which is why BLO was used in paints up until modern chemistry gave us the alkyds, and seems to resists wear and tear/ minor damage better. I prefer BLO on anything that is going to get rough use, and tung on things like interior woodwork, especially to avoid the yellow tint that comes from BLO. Tung (probably because of that added hardness) also gives a much finer/nicer 'satin' appearance when rubbed out, BLO can look fine for more rustic stuff, less so for anything high end.
As far as when to apply subsequent layers, dry to the touch is the best standard without any further experience. Yes, it still may not be totally dry, but until you get a feel for the process and the products, there really isn't much else to go on. That same gummyness can occur when you rush applications of shellac, with oils I find it to be most problematic when there is any solvent present - as it is the migration of the solvent between the older and newer layers that seems to create the most problems. Personally I only use solvent for the very first layer, which I also apply warmed (warm the oil, then add the solvent, then apply) and only apply as a fairly moderate layer (I'm not one of those 'saturate the wood' people.)
There are probably as many variations to true oil finishing as there are wood finishers, The true beauty of these finishes is that they are amazingly forgiving, and with enough time and effort will most always yield something acceptable if not downright good. I have a theory that part of the wonder of oil finishes is directly related to the very physical nature of the process, especially all of the non-abrasive rubbing action, which alters the immediate surface of the wood in ways that other finishing techniques do not.
As far as when to apply subsequent layers, dry to the touch is the best standard without any further experience. Yes, it still may not be totally dry, but until you get a feel for the process and the products, there really isn't much else to go on. That same gummyness can occur when you rush applications of shellac, with oils I find it to be most problematic when there is any solvent present - as it is the migration of the solvent between the older and newer layers that seems to create the most problems. Personally I only use solvent for the very first layer, which I also apply warmed (warm the oil, then add the solvent, then apply) and only apply as a fairly moderate layer (I'm not one of those 'saturate the wood' people.)
There are probably as many variations to true oil finishing as there are wood finishers, The true beauty of these finishes is that they are amazingly forgiving, and with enough time and effort will most always yield something acceptable if not downright good. I have a theory that part of the wonder of oil finishes is directly related to the very physical nature of the process, especially all of the non-abrasive rubbing action, which alters the immediate surface of the wood in ways that other finishing techniques do not.
It makes complete sense that knowing when something is dry enough is knowledge that comes from experience, and that's what I'm trying to build up here! I've already been approaching things a bit differently than my first refinishing project (a stripped-down Dean where I first tried tung oil and eventually stripped again and finished with wipe-on poly). With my test pieces I've noticed that the tung seems to be penetrating pretty deeply into both the alder and korina (I've done two coats so far with 50/50 mineral spirits) and the tru-oil seems like it's sitting on top of the wood, which seems consistent with descriptions I've read here. The tru oil pieces are drying out fairly quickly, but I'm still waiting at least 12 hours or so between coats, and the tung pieces for more like a couple of full days (three days between first and second coats). Better safe than sorry, even if I'm just experimenting. The oils on the korina are looking especially cool already, even with just a few coats. I'm waiting on some grain fillers (clear and black) from Stew Mac to try those with each of the oil types as well on different scraps. I have a feeling it's going to be some time before Warmoth sends my stuff, so I have some time for experimentation. Thanks again to everyone for the advice.
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