I am working on a project with a couple of small cracks I would like to fill. They measure two to three inched long, about .018 inch (about 4 or 5 sheets of paper) wide, and maybe 3/8 to half inch deep. They are right in a corner. I think putty fillers are too thick to work into them. I have some thinner for the putty but I am not sure how much I could thin the putty and still have it bond and stay put. The project is red oak and is going to be finished dark using Espresso, which is a General water based stain and wipe on poly for a top coat.
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They look small enough that the finish itself may be enough to fill them however, I am not sure that will work. Any suggestions on filler that would be thin enough to fill such small cracks.
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Thanks,
Bob T.
Replies
I would use a low-viscosity transparent epoxy, which can be tinted to match the wood (although that might not be necessary, considering how dark you're planning to stain it). Unfortunately, it's hard to get that kind of epoxy in small containers, so I'd go with an off-the-shelf epoxy that you should be able to find at a hardware or big box store. If you can find one that is slow-setting (not 5 minutes), all the better.
Mask off the surrounding wood, to avoid getting any epoxy into the pores. You should have as small an exposed wood surface as possible. Work the epoxy into the crack with a thin blade; an X-Acto knife is perfect, but a razor blade will do. You don't need to completely fill the crack, but you do want to completely wet the inside of the crack near the surface with epoxy.
As the epoxy starts to set up, slice off any large blobs, but don't try to get too close to the final surface level, or you risk going too far. Sand level after the epoxy is fully cured.
Practice on a test piece first!
-Steve
This post brings up a point I've been meaning to ask about for awhile. I got a great price on some curly cherry last year and have run thru almost all the clear stock. There is a lot of beautiful wood left, but many of the prettiest pieces have tiny pin knots for lack of a better description.
After I finish the wood, the holes, maybe 1/16" diameter at most, are aways visible whether I use oil, varnish or shellac. And they are more noticable with a glossier finish, like a table top.
The last piece I made, a Pembroke table, had one tiny little spot, and it ended up on the leaf. As much as I hated to do it, that is potentially muddy the finish, I sanded the whole top with an oil mixture, let it develop into a slurry, set for fifteen or twenty minutes, then wiped it down, and repeated a couple of days later. I let it dry a week or so before applying a shellac finish. It felt and looked smooth until a couple of coats of shallac went on, then the pin knot stuck out like a sore thumb again. Any ideas on finishing these pieces?
For something small like a pin knot, I think the burn-in shellac (or lacquer) sticks mentioned previously in the thread should work pretty well. The reason I wouldn't recommend them for the kind of crack that the original poster asked about was the size of the crack--a 2-3" long by 3/8" deep crack borders on "structural" rather than "cosmetic." Because shellac is brittle and not particularly strong, I don't think it would last too long in that kind of repair.
You can also use wax sticks. They have the advantage of not requiring heat to apply, and it's all but impossible to mess up with them, but on a hard-use surface like a tabletop, they're suitable only for very small holes (1mm or less), because the wax remains relatively soft.
-Steve
Thank you. Would you use them after sanding/scraping and before applying any finish? I guess you'd need something a little darker than the wood?
And as a followup, is it too late to use a shellac stick on my Pembroke table leaf? I'd planned to rub out the shellac in another day or two.
While you have more control if you do it before you do any finishing, they're actually intended to be used after finishing as well. Obviously, you need to be careful, and mask off the surrounding area. As for color, that's always a judgment call. For something as small as a pin knot, where you're going to be able to see that there's a knot anyway, the color doesn't really matter too much, as long as it's dark enough not to stand out.
I'd suggest taking another piece of the wood [one with a pin knot, of course ;-) ] and practicing with it first.
-Steve
Edited 7/7/2008 10:09 pm ET by saschafer
To fill any small blemishes (cracks, nail holes, miss-cut joints, chip-out...) in wood that is to be stained, I have found it is easier to stain first and repair second. I use shellac sticks or simply colored wax during the finishing process. Mohawk Finishing has several options. In your case, those small cracks might very likely simply "go away" after staining and finishing. If they don't, some colored filler will take care of it. It is infinitely easier to match the color during or after finishing. If you use any epoxy or super glue before staining the glue will very likely bleed onto the wood surface. That glue will inhibit the stain or dye from coloring the wood. Yes, you can then tint that spot but "blending in" is a difficult process to learn.
Liquid hide glue mixed with sanding dust from the lumber prior to staining. Or the wax sticks, they can be melted and mixed to obtain the proper colour(use after finishing).
Work Safe, Count to 10 when your done for the day !!
Bruce S.
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