What Thin Glue Can Fix Loose Chair Joints?
Issue: Issue 318
Posted Date: 1/22/2013
I would like to reglue my maple dining room set. I would like to use a very light sort of watery glue that would get way down in the wood, and not just a surface-thick glue that would just glue the upper part of the stem. What type of glue would you recommend? - Ronald C. Colongione
Rob Johnstone: I think I understand your challenge … there are cracks developing in your table, and you are hoping that you can get some glue into the cracks and clamp it back together. I think I have some bad news for you -- if these cracks are delaminating glue joints, I think the likelihood that you will succeed is small. The existing "failed" glue in the joints will hinder your effort because it will not provide a good surface for a glue bond. Also, you may have a dickens of a time clamping the pieces back together, as I suspect that the reason the glue joint failed was distortion from seasonal wood movement.
In general, the way to fix a failed glue joint is to break it completely apart, scrape the old glue from the wood and then re-glue and clamp. But with that said, you will lose nothing by giving it a try. If I were you, I would thin regular yellow woodworking glue (Titebond is an example) mixed about half and half with water, and work it into the joint with a very thin piece of paper or film type plastic (X-ray negatives are used by some woodworkers … they are stiff but thin). Get as much glue in the joint as you can, then clamp the whoopy out of it, cross your fingers and hope for the best.
Tim Inman: This will sound rude and blunt. I do not intend to be rude, but I must be blunt here. You cannot soak watery glue into a bad joint and fix a problem. You must open and clean all the wood surfaces, and fit them together correctly, before applying a proper coating of glue if you want a successfully repaired and bonded joint. Simply applying glue and hoping it will somehow find its way into the joint and magically rebond the wood successfully is folly. In our shop, we often see glue "icicles" dripping from chair legs where good intentions have crossed wires with good sense and good practice. The reason we see them is that the work failed, and the piece finally shows up in our shop for "another" repair. We call it, irreverently, the "Pour-on-the-glue-and-hope-some-sticks!" technique. It doesn't work. It never works. It will not work, ever.
I might add another critical comment, as long as I'm already being harsh. Diluting glue in order to thin the viscosity also thins or dilutes the bonding strength of the adhesive. You might get some glue to flow or be drawn into the area, but mostly, it is water that is flowing in, and very little adhesive resin. The water will swell the wood -- so you might think it has worked to tighten the joints. The "fix" is temporary. Eventually the water evaporates, and the wood shrinks away, and the joint is just as loose as it ever was. The only difference is that now we have even more junk glue to clean off the wood and out of the joint before we can accomplish a good repair.
And finally -- you thought I would never give up on this one! -- almost every wood glue commonly available has poor "gap-filling" ability. These glues need to have (must have!) close wood-to-wood surface contact in order to effectively bond. They will not bridge over gaps between wood surfaces and be strong. They will clog up the cracks, but they will not bond the two woods together. You must clean and fit the joints together before applying a proper coating of a good adhesive in order to effect a proper bond and repair.
Please forgive me if I have offended; that is not my intention. I want you to have the best available information before you begin your project. I'd rather you be a little disappointed now than greatly disappointed and discouraged with poor results later on.
The problem I have is where the back dowels come down into the seat part of the chair. They are loose, and I would like to have a glue thin enough to go down into the hole where the dowel is, without taking the chair apart, and just reglue it that way. - Ronald C. Colongione
Rob Johnstone: Well in that case there is a product called Wonder Loc 'Em that is designed to be squirted into chair joints to fix this problem I have not used it, so I cannot tell you how well it works. I put a link to it from the Rockler Woodworking and Hardware site.
Chris Marshall: Ron, I'll offer a radical suggestion here: have you considered driving a short 18-gauge pneumatic brad through each loose dowel right where it meets the seat? If you shoot them carefully at a low angle and from the back side of the chair, they'll cross-pin the dowels to the seat board and lock the joints. I absolutely retract this suggestion if your chairs are precious family heirlooms (in which case, get them fixed by a professional with Tim's pedigree!), but if these are mainly "workaday" chairs and you want to get a few more years of life out of them, you might be surprised at how well little brad heads blend in once they're countersunk. Just another option to dismantling, removing old glue and starting over again. Or, hoping more glue will fix the problem. Good luck!