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I am refinishing an old Remington 870 stock birch stock. I stained it with a dark cherry colored stain, and then began to apply Hope's 100% tung oil. I had read to wait at least a day before sanding and applying the next coat, though that seems to be a short period of time. However, when I sanded the stock, much of the stain I had applied was removed along with the tung oil (if I recall correctly, I was using 340 grit paper, and I had cut the first application of oil about 50% with mineral spirits).

I decided to restain the whole stock, and ended up staining it several times, letting it dry and wiping down with mineral spirits to remove the tackiness between each coat (I know that multiple coats are generally advised against, but the birch wasn't accepting the stain evenly and this helped me get a fairly even, nice stain). The stock is now fully dry (wiped the access stain off a day or two later with the help of mineral spirits, and then let dry for a week).

My question is: is there a way to properly apply tung oil to the stained wood without removing the stain during the sanding process? Do I simply need to wait longer for it to dry, not sand between the first couple of coats, use a finer grit sandpaper, or what?

Bonus question: This being my first woodworking project, my sanding left something to be desired. There are very minor sanding marks in the wood that I didn't notice before staining. They are mostly in the same direction of the grain of the wood, but a few of the swirls I didn't match perfectly. Is there anything I can do to fix this without removing the stain and starting over? It doesn't bother me very much, but I would feel unacceptably lazy if I didn't even make an effort to fix it.

Sanded down picture of stock Stock after being stained

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    Birch is notorious for being blotchy when finished, which could explain your issue with getting an even stain. How much did you sand after applying the tung oil? Should only be enough to take off the bubbles and high spots, not to go down to bare wood. Also, it's possible that the tung oil is diluting the stain, but it's hard to say without knowing exactly what stain you're using. – grfrazee Jul 21 '15 at 17:05
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    Yeah I was expecting it to be difficult, but taking the time to stain, dry, clean with mineral oil, and re-stain really helped even out the color. I should mention I'm using 100% tung oil. And I was sanding fairly lightly and not very much, but pretty much right when the paper hit the wood I could see pink tinted wood pulp. I've read that with tung oil the first couple coats will get fully sanded away and the pulp mixture will fill in all of the imperfections in the surface, but I have no idea if this is true and, if it is, with the stain beneath it I really don't want that to happen anyways. – Matt Walck Jul 21 '15 at 17:12
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    @grfrazee I can check the brand of stain in a few hours, if that would help! – Matt Walck Jul 21 '15 at 17:14
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    It might, but it could just be a shot in the dark. However, I find that there's no such thing as too much information when asking a Question. – grfrazee Jul 21 '15 at 17:36
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    Eh, I don't think that's really necessary. Taking a look at the answers provided below, I think there is enough information there to diagnose your issue. – grfrazee Jul 22 '15 at 12:51
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My question is: is there a way to properly apply tung oil to the stained wood without removing the stain during the sanding process?

Yup: don't sand.

Drying oils are not a surface coating, they're a penetrating finish, so basically there's nearly no difference between sanding oiled wood and directly sanding the surface of the stained wood, which many guides specifically warn not to do.

Even when sanding a film-building finish (shellac, varnish, lacquer) great care must be exercised not to sand too much as if you break through the finish you can almost immediately reveal bare wood because stain penetration is extremely shallow.

Drying oils don't need to have the previous application sanded if they're applied appropriately. While it's become common advice to sand or scuff the surface when applying subsequent coats of tung oil in particular, but BLO as well, this is by no means the only way to do it.

The traditional method for applying drying oils specified that the surface should be wiped extremely thoroughly after application and in fact buffed hard with the wiping cloth, which ensures removal of all excess oil from the surface, and simultaneously burnishes the surface of the wood. Both of which were considered vital to the development of a good oiled finish.

There are very minor sanding marks in the wood that I didn't notice before staining. ... Is there anything I can do to fix this without removing the stain and starting over?

Basically your options are scraping or sanding to remove the marks, unless you switch to a film finish which can hide minor surface defects.

An oiled finish magnifies flaws, doesn't hide them, which is why surface prep for an oiled finish must be done more conscientiously than if using varnish, e.g. sanding to a higher grit. FYI when varnishing there's no benefit to sanding beyond about 220 grit and in fact you can often get away with stopping at 150, while if you're doing an oil finish it can be advisable to sand beyond 400.

Bonus answer to a point in one of your comments above:

I've read that with tung oil the first couple coats will get fully sanded away and the pulp mixture will fill in all of the imperfections in the surface

That's true to a degree but actually not the ideal way to go about doing this.

If you want to fill pores in the wood it's far preferable to use a grain filler, either homemade or commercial. Preferable because the results can be superior, and you get there faster and more reliably.

Since you might ask, homemade grain filler can be made from fine sanding dust (220 grit or higher) mixed with varnish; some people use oil as the binder but varnish sets harder and faster so it's preferable. You could also experiment with using wood glue.

  • Thanks! I had heard to wipe it down afterwards, but I hadn't heard to really buff it all off afterwards. Does the advice to not sand between coats only apply to the first few, or even after 5-6 coats I shouldn't sand in between? What about the last coat to polish the surface? Also, would fixing the sanding marks with a grain filler be possible without re-staining? or is my only option at this point to either accept the marks or redo my work? Also, in regards to sanding to a higher grit, I had heard this would affect the acceptance of stain, is this true? – Matt Walck Jul 22 '15 at 12:09
  • Apologies for the machine gun fire of questions, this is my first woodworking project so I'm fairly ignorant on the basics. Thanks for the help! – Matt Walck Jul 22 '15 at 12:15
  • @MattWalck, "or even after 5-6 coats I shouldn't sand in between?" yup. Oils are not film-building finishes. Lightly scuffing with fine steel wool is the most I would do personally. "Also, would fixing the sanding marks with a grain filler be possible without re-staining?" I don't think so I'm afraid but you could try it. "Also, in regards to sanding to a higher grit, I had heard this would affect the acceptance of stain, is this true?" yes that's possible. The finer you go the more you'll tend to get this effect. – Graphus Jul 22 '15 at 13:05
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    @MattWalck, you don't "final polish" oil finishes by sanding. The surface just gets glossier as oil builds up in the surface wood fibres and from the rubbing. The entirety of the traditional method for linseed oil is wiping on oil, wiping off oil, buffing the surface dry. That's literally it. You just repeat that 9-20 times. – Graphus Jul 22 '15 at 14:16
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    @MattWalck, honestly with drying oils the wait time between coats is so variable anything you read is just a rough guide. Even with BLO, which has a more uniform drying time, you're supposed to wait just one day for the 7 coats. But if you're living somewhere warm and dry 8-10 hours might be enough. In the winter where I am I'll wait 2-3 days, because it's cold and damp. Now with pure tung oil, those same things apply, but also the oil itself can vary because it's a natural product and is inherently variable. If your surface is at all greasy feeling or smells too freshly of oil, wait longer. – Graphus Jul 23 '15 at 10:37
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The sanding between coats is entirely for the keeping a smooth finish. Any bubbles or raised grain are knocked back. When I sand, I rarely pass the sand paper more than a couple light passes. then check for visual and touch cues to see if anything more needs some extra sanding, say a drip that dried. If you are sanding away the stain you are sanding too much. It is also possible, especially with cutting the finish down, that you might not need to sand between each coat.

  • Would it be okay to simply feel the wood to check for bumps for the first few coats, and not sand at all? And would 340 grit be good, or should I got up to an even higher grit? – Matt Walck Jul 21 '15 at 18:02
  • @MattWalck That's how I do it. Though often I use poly, so I usually need to do a little sanding. 340 should be fine in my opinion, unless you are looking for a high gloss finish. – bowlturner Jul 21 '15 at 18:05
  • Slightly off the topic of this post, but do you find that poly is a better finish than BLO or tung oil, and if so why? – Matt Walck Jul 21 '15 at 20:15
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Something that nobody's mentioned so far is that if your stain isn't penetrating, you've got another problem.

If there's a previous finish still on top of the wood, forming a seal, stain won't penetrate, and the least bit of sanding will remove it.

'Sticky stain' is a very common symptom for this.

If that's the case, you might want to try to strip it again, and try a wash with something like acetone, lacquer thinner, mineral spirits, and / or turpentine. One of those should cut the finish and allow the stain to penetrate.

  • Originally, I did not strip the wood, I sanded the old finish entirely off down to the bare wood. Could there still be something sealing the wood after that? – Matt Walck Jul 21 '15 at 20:37
  • A good finish penetrates into the wood, saturating the wood fibers, filling any pores and irregularities. If you were just re-finishing the wood without any kind of stain, you wouldn't even notice that there's any original finish left (unless the new finish wasn't compatible with old.) With a piece you plan to re-stain, you really have to be aggressive with the stripping. – TX Turner Jul 21 '15 at 21:29
  • Interesting... is there a reason to re-strip and re-finish the piece if I can successfully add the tung oil finish without sanding off the stain? – Matt Walck Jul 21 '15 at 21:52
  • Also, additional info that may be helpful: I was told that the stock was a laminate stock made of birch. I don't really understand the properties that the laminate granted, but whatever they were it appeared to me that I was able to fully sand down to the bare wood. Whether or not this assumption was correct, I'm not sure – Matt Walck Jul 21 '15 at 21:54
  • Laminated birch plywood? Multiple layers of alternating color? I've seen stocks like that, they're supposed to be great for outdoor use, not suffering some of the cracking / expansion / contraction that a single piece of wood can. If you can get the stain to stick and the finish to dry, there's generally no reason to start over. However, you might notice in a couple of months that the finish is brittle- chips easily. If that's the case, you know what to do, hehe. Additionally, the glue from the lamination may be getting in the way. – TX Turner Jul 21 '15 at 21:57

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