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Well, when I get paid this Friday, I'm going to need to get some Tung Oil for my current project. Some people on here said it doesn't yellow like BLO, and that's a feature I want. I'm applying a water based coat on top of it, so I know I'll need to let the oil dry for a couple or three days before applying the topcoat, but that's fine. I want to pre-finish the parts, as they are easier to sand like that. Some parts of my project (the Maple-veneered ones) are ONLY getting a water based topcoat, so I don't need to worry about those.
I was wondering what brand to buy. I know the Minwax "Tung Oil Finish" is, at least as far as I can remember, just a modified varnish rather than true Tung Oil. I'm wondering what I should look for and what I should avoid. Thanks!
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Hello - others will likely 'chime in' w/ their recommendations - I've used BLO in the past but not 'tung oil' - just google 'pure tung oil' and there will be plenty of hits, such as the one below ( LINK) - pure tung oil w/o additives is derived from pressing seeds from the tung tree nut - there are plenty of other brands, so just look at the reviews/comments - Dave
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It needs to be labeled 100% tung oil, the presence of anything else means it's not. I live out on the sticks so this may not be a problem for you, but I don't recall ever seeing real tung oil available around here. if I ever want some I'll have to order it in.
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I might give that Hope's stuff a try. Does Pure Tung Oil take forever to dry, or is that just with non-boiled Linseed Oil?
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(02-04-2018, 02:36 PM)KingwoodFan1989 Wrote: I might give that Hope's stuff a try. Does Pure Tung Oil take forever to dry, or is that just with non-boiled Linseed Oil?
Hi again Kingwood... - first, BLO = Boiled Linseed Oil which is not boiled but has drying additives; non-treated linseed oil would take days to dry and is not used for finishing. Second, 'pure' tung oil will take longer to dry vs. BLO but certainly 'not forever'. The link given for Hope Tung Oil describing the interaction w/ the wood is somewhat over done IMO - neither drying oil will offer much 'protection' vs other finishing options - see the comments below from Bob Flexner ( LINK) - Dave
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Most people thin Tung oil with either mineral spirits or citrus solven to increase penetration and speed up drying.
https://www.dtep.com/hc02001.htm
Drying times can and do vary with air flow, temperature, humidity, and number of coats so would only be a SWAG to provide anything you can take to the bank.
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I'm only using the oil for color-deepening under a water-based topcoat. Would thinning the pure tung oil 50% with mineral spirits like the Hope link earlier describes help it to dry within a couple days to where I could put the water-based topcoat on? Ordinarily I'd use an oil-based poly, but those take longer to cure, so I'm doing it this way.
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(02-04-2018, 07:25 PM)KingwoodFan1989 Wrote: I'm only using the oil for color-deepening under a water-based topcoat. Would thinning the pure tung oil 50% with mineral spirits like the Hope link earlier describes help it to dry within a couple days to where I could put the water-based topcoat on? Ordinarily I'd use an oil-based poly, but those take longer to cure, so I'm doing it this way.
Well, I've used 'tung oil' just a few times - more often, the thirds combo finishing formula (i.e. BLO + MS + oil Poly) is what I've preferred - point is combining a drying oil and then wanting to apply a WB finish is a different consideration. If you are set on using the tung oil w/ WB poly, then you will need to make sure that the oil is indeed dry & cured (this may take several or more days depending on many factors) - of course, if time permits you could do a number of finishing regimens and timings on scraps from the project to make absolutely sure the finish is what your want and is stable?
NOW, what I would probably do w/ your desired regimen is to apply the tung oil (how many coats is up to you?), then wait a number of days (cannot tell you how many?), next apply a 'sealer coat' (I would use non-waxed shellac - the easiest way is a rattle can of Zinsser Bulls Eye), then do your WB clear coats - should work fine. Others may have a different opinion? Dave
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(02-04-2018, 07:25 PM)KingwoodFan1989 Wrote: I'm only using the oil for color-deepening under a water-based topcoat. Would thinning the pure tung oil 50% with mineral spirits like the Hope link earlier describes help it to dry within a couple days to where I could put the water-based topcoat on? Ordinarily I'd use an oil-based poly, but those take longer to cure, so I'm doing it this way. Thinning it will help. You can also add a tiny amount of Japan Drier - it catalyzes the cross-linking and expedites drying. It will itself also darken the tung oil a bit.
Note that Japan Drier is toxic (as is MS) and will negate any non-toxic properties of pure tung opil, if those are important to you.
Lee Valley gives some guidance on tung oil dry times.
http://www.leevalley.com/us/shopping/ins...px?p=44433
-Mark
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Some facts to think about:
Most top coat oil or water base finishes will high light any grain or figure present in wood. Most top coat finishes reach 90% cure in nine or ten days and full cure in as much as thirty days.
All manufacturers or vendors will tell you thinning pure tung oil aides in penetration and shortens drying times. If given enough coats (4 to 5) get some build of protection. Note See Bob Flexner’s book for reference.
Commercial oil varnish blends can contain less expensive semi-drying oils thanks to chemistry. Just read products MSDS or SDS which may or may not list oil actually used. Only required to list hazardous components!
Home brew oil varnish blends seldom use anything else than BLO in the 1/3 rule of Resin (varnish or poly), BLO, thinner/solvent. You do not get more protection no matter how many coats you apply due to diluting the resin! Some commercial blends will give you more sheen than others or home brew mixes.
Many commercial products listed as tung, teak, or danish oil are wiping varnishes! You can make your own with 50/50 mix of resin & mineral spirts. Two coats should equal one coat of resin! Don’t buy a commercial wiping varnish with more than 60% mineral spirits or other thinner/solvent.
Please see Flexner’s article for better explanation!
https://www.popularwoodworking.com/techn...ry-and-use
Bill
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