Scarf joint wood splice chair repair
I offered to fix some that were beyond just gluing back together, so I took three of the broken back legs and one of the chairs to my shop to fix it.
The ends of the wood were beyond re-gluing again. My first thought was to put a "patch" piece on to bridge the gap, but insetting it into the wood so it wouldn't stick out. To get a better connection at the end of the patch, I figured I might angle the ends, as shown at right. But this would be a lot of work.
And a cool machine to cut this sort of joint is a pantorouter, naturally... The pantorouter is always the answer :)
I'm using the aluminium one sent to me by Kuldeep, with a wooden template cut from scrap wood.
Next I need to make the patch pieces. I first experimented with tilting the saw blade and using my tenon jig, but when cutting tenons, the saw teeth are cutting out of the grain. Cutting out of the grain is much less efficient and really bogs down the saw.
So I rigged up an angled support on my small table saw sled and cut the ends that way.
I had to make sure the cuts were the right distance from each other. The critical part, aside from the angle, is to have the shallow corners the same distance apart as on the cut-out.
This meant I had to wait for the glue to dry. But it turns out, the fit wasn't perfect, and I didn't use enough glue or wait long enough. So it came apart when I took it out and started working on it. But the second time I glued it I used more glue, more clamps, and let it dry longer.
The patch is deliberately about 1 mm thicker than the wood. I figure a bit of extra wood will make it stronger.
I left it clamped for about three hours. Though in retrospect, I think it would have been better to leave it clamped overnight.
I used my acrylic paints and mixed half black and half burnt umber to try to match the colour of the original stain.
The colour came out surprisingly similar considering I wasn't even using the same type of oak for my patches. I then put two coats of water borne varnish on top of that to give it a shine like the rest of the finish.
Many of the chair's joints had been re-glued with epoxy repeatedly. I figured epoxy would probably be better at sticking to whatever glue residue might still be there. It's also better at filling gaps because it isn't runny.
I used five minute epoxy. I would have preferred a longer open time, but the only epoxy suitable for wood at the Home Depot was five minute epoxy. I managed to get it all together in time though, so all was well. (Yes, I'm sure it's possible to get different epoxy elsewhere, but it wasn't worth looking for, and it's now done, so I don't need a dozen people to email me about it)
I'm quite happy with how closely the colour of my patch matches the rest of the chair.
There were screw holes through the legs and joints from previous repairs. I figured, a reinforcing screw would be a good idea. but I put the screw off to the side and at an angle instead. That way, the screw doesn't weaken the joint itself, and gives extra leverage to resist leaning back on the chair.
There was no attempt at hiding the previous screws, so I didn't cover up these screws either.
They are nice chairs, but the poorly designed joinery makes them quite weak. If these chairs were mine, I would probably have given up on them a long time ago.
Another chair leg repair
Building kitchen chairs