How to Repair Wood Cracks
George VondriskaA natural piece of wood comes with its fair share of imperfections and cracks. In this video lesson, master woodworker George Vondriska teaches you how to repair cracks and fill uneven areas in your wood to achieve a smooth finish on your woodworking projects.
You might also be interested in: Furniture Leg Repair—How to Fix a Broken Leg, Repairing an Old Chair, or Restoring Veneer on an Antique.
The project that I'm working on here is a paint-grade project. That means that, instead of staining and sealing it, I'm gonna put a layer of paint on this when I'm done. And what I've got in it here is a very large knot. That knot has a big crack in it, it's also got just some checks around the edge, and if I paint over the top of that, the paint is gonna sink right into those, and that of course is gonna show up when I'm done, so I want a good, easy way to fill that in. Baking soda and CA glue works so well, you're not gonna believe it, it works really, really good for this.
I'm going to take some baking soda and sprinkle it liberally on there. Then using a putty knife, I'm gonna work it down in and also get the excess off the top here. Now CA glue, that's cyanoacrylate, and I want the thin form of that, so that as I apply it, it's gonna drip right down in, it's gonna saturate that baking soda and get all the way into the bottom of those voids. So just follow any place where the white stuck. Don't worry too much about getting too much on, 'cause you will end up sanding over the top of this to level everything out anyway.
That's about it. Now you need to give that just a little bit of time to dry, and then we can come back and sand it all flush. Once the glue is dry, what you'll probably find is that you have kind of a buildup on the surface. So a little bit of sanding. Will get that knocked down.
Once you've got this leveled out, what you'll find is that you'll have a surface there, you can paint right over the top and you'll never ever know that you had those voids, those defects there down below.
I have used the sawdust plus CA glue with some problems. First, it dries much harder than the underlying wood, so when attempting to sand it level, it tends to stay up a bit. Stain over any glues or fillers is often a problem but with CA glue, it seems to be less so, perhaps because it dries so hard that tiny sanding scratches allow the stain to settle in them. Work with walnut and sapele, I have found that CA tends to stain a lot better than the 2-part wood fillers or the colored plastic wood fillers. On the lathe, when small pieces chip out, rather than sand it down to a smaller diameter, I have achieved pretty good results when I fill the crevasses with the plastic wood filler (of appropriate color) and then apply the CA glue on top of it. Adding wood particles isn't necessary for that and often isn't hard enough. Humidity activates the CA glue. The acetone and MEK in the plastic wood filler helps to dissolve the CA glue a little bit and that helps the CA penetrate into the filler. After it totally dries, it can be turned again on the lathe, sanded and when stained, it usually doesn't appear as a repaired defect.
great idea
Years ago when I worked at a factory that made custom wood doors & windows, we used a very similar technique to fill small cracks or gaps in a door or window frame. We would use the same technique you describe below with the sanding dust and then sanding over it, but we used a little yellow wood glue. CA glue was not as readily available or cheap back then, but the yellow glue worked well and the results stained beautifully. Might prove handy if someone is caught with their glue pants down.
Being deaf, captions would sure help here, I had no idea what liquid he was using until I read the comments.
Any tips for coloring the baking soda - e.g., to patch/fill walnut?
This looks a very neat idea. Is there a chemical reason for using baking soda?
how to fix a crack in wood whats the name of the glue that is used
I’m sorry please repeat......what is CA glue....... it looked like a super glue.....is it something like that?
Hi George, Will this work with a vertical crack in a doorframe? If not, dwe you have any suggestions on how to repair it short of replacing the entire frame?
Gorge what if you have a crack or a void in oak and a person wants to stain it? Bob