*
Hi all. Longtime listener first time caller. Yesterday, I glued up my first table project–a Hepplewhite-style end table (tapered legs, square top, single drawer). I was pretty excited about it, since I’d cut pretty much all the joints by hand, and while they’re not perfect, they’re pretty good, and it went together OK.
Anyway, I glued it up in two stages (using yellow wood glue). First I did the front two legs and the back two legs (with this rails and stretchers, of course), taking some pains to make sure they’d be square. Then, after they’d stabilized a bit, but before they were 100% set (about 45 minutes), I proceeded to glue up the rest (the remaining stretchers connecting front and back).
Somewhere in the process of the full glue up, things got out of square. I’m not sure where, exactly, as it was square as near as I could tell (using a square) when I walked out of the shop. When I returned a few hours later, I found that what I’d glued up was not square, but was, in fact, a parallelogram. It’s about 3/16 off over 17 inches, which is enough to create a real problem with a drawer (which I haven’t built yet), because one side of the drawer is going to want to stick out when the drawer’s pushed in.
So here’s the real question: is there a way to undo my disastrous gluing job? Can I steam the whole works apart or something? Or am I stuck having to figure angles and make the drawer into a matching parallelogram so that it sits straight in the opening. I could make the drawer a little undersized, but I’m worried that the front will tend to sit more to one side or another in it’s opening.
Can a glue up with yellow wood glue be undone?
Replies
*
Hi,
Someone told me that acetone would quickly break PVA joints – and much cleaner and with less damage to the wood fiber than water/steam. Never had to try it myself, but it’s worth a shot. Please let me know if it works.
Next time you’re doing this, if you notice the piece is out of square (even after a half an hour or more, depending upon how stubborn you are) you can almost always correct it. PVA stays pretty plastic except in the hottest weather for quite a while. My x-shopmate, Kirk Schuly, used to say: “The glue is dry if you need the clamps, but not dry if you need to correct the glueup.”
Hope this helps.
Regards,
Kim Carleton Graves
Carleton Woodworking
*You can guess how anxious I am about this, since I'm checking back about every 5 minutes.Thanks very much for that tip on the acetone. I'm fresh out, but that's easily obtained, and I think I may have a test joint or two I can try it out on.As to the elasticity of the glue--as I think I said, it was quite a few hours before I found the problem (probably five). I did go ahead and build up a jig that was nice and square, and clamped it in there overnight, sort of hoping that the joints might still move enough to make it OK. I haven't checked today, but your post makes me at least a little hopeful.
*Bikeboy:If the acetone works, please let us know. It has a high vapor pressure which means you can readily smell it and it evaporates quickly. But please be careful - it is very flamable and that vapor can seep to an open flame just like gasoline. But please do give us an update.
*Hi,Five hours is probably too long – depending upon the temperture. I'm talking more like an 30 min - hour. You should check for square as you’re doing the glue up. The fastest and most accurate way is to check the diagonal measurements. Do you know how to do this? The diagonals of any rectangle are of equal length if the four angles are square. So measure across the diagonals as you’re doing the glue up and adjust your clamps accordingly. This is much faster and more accurate than trying to use a square of some sort. Also doing a dry glue up really helps. Hope this helps.Best,Kim Carleton GravesCarleton Woodworking
*Heat softens PVA adhesives. I use an infrared heat lamp. Direct it toward the joint for 5-10 minutes. A good, sharp wrap with a dead blow or heavy rubber mallet generally gets joints apart.
*I'm clear on how to determine squareness and all that--I think the problem was that I only clamped one diagonal. In retrospect it's pretty plain what the issue was, but at the time, I was thinking, "I'll just push it as far as it needs to go in this direction and that'll do it," never thinking, of course, that any tightness in the diagonal clamp would eventually lead to overrun. That is, it went on and pushed it past where I wanted it.The re-clamping overnight was really just hoping against hope--I figured I didn't have anything to lose, and thought it might work, though I kinda figured it had been too long.I'll try some methods to get it apart, but I may just have to call this one a learning experience.
*It's solidly glued by now. Salvage the situation by either1) Building a parallelogram drawer (not real easy, and lots of fitting needed on the parts) or 2) Build a square drawer, make the front extra thick, blind dovetail as usual, dry fit, mark the extra 3/16" taper, take the drawer front off, and plane or sand flat to the line. Cut a tapered piece of wood for the drawer to butt against in the rear.
*I really hate glue ups. It drives me nuts. It helps if you have all the clamps opened the correct amount, all the cauls at hand and everything dry fit for a trial run before glue up. I use hide glue on complicated stuff. It sets up alot slower and you have time to fix screw ups.Hang in there!Frank
*Thanks for all the answers. Here's what I've got so far:Acetone does not seem to work. It does make a white film form on the surface of the glue, but does not penetrate. It did make a little droplet easier to knock off--I think it made the glue more brittle--but it did not penetrate in any meaningful way. I don't know about other wood glues, but I can report that acetone does not dissolve or significantly weaken proper glue joints made with Elmers Yellow Wood glue. At least not mortise and tenon ones.Heat was a similar wash out. I haven't yet tried the long-exposure-to-heat-lamp trick, but a heat gun was not able to heat things to the point that the mortise glue weakened (It's cherry, so I didn't want to turn the paint stripper on it too long--it heats too fast). On the upside, the surface drip I was testing for softness did get soft, and once the heat was off, it hardened back up. I don't know that I'd trust heat softened glue to hold anything together after it hardens back up, but it does suggest that you can scrape your joint clean after breaking it apart. Just let the glue cool, and it'll behave more or less like regular glue you can scrape without gunking up your tools.So while long gentle heating may well do the trick, there's no fast way to do this, and the heavier your pieces are, the harder it'll be to keep the heat in well enough to get at the core, where the most glue is. I think I could have heated up the top drawer rail enough to get the dovetail apart, since it's only 1/2" thick, but I doubt I could ever get the 5/8" x 3" tenons out of the center of 1 1/2" thick legs.My new plan on this is to use a thin kerf handsaw with little or no set (flush cut saw?) to saw the side stretchers away from the legs. Then I'll use the tablesaw to re-square the ends of the stretchers, plane the legs flat with the tenons in place, and re-make the joint with either loose tenons or dowels. Maybe I'll try beadlock. This is not going to be a serious weight-bearing table, so I'm not too worried about real strength. If it'll hold up the phone and a lamp, it's great, so I may just go with 3 dowels.I'll lose a little length front to back on the table, probably 3/16" overall, but I won't lose sleep over that--since it's not built to any particular tolerances, I could lose a lot more depth than that and still be happy with it. The lack of squareness, on the other hand, I can't deal with.
*Interesting about the acetone - thanks for reporting back. Sounds like you have a soild plan, well thought out to fix things. Remember a good craftsman is able to recover from a problem/mistake and move on - sounds like you are doing that! Good luck!
*Bikeboy, I'd be careful and cautious about cutting dead-on between the stretchers and legs. It's easy to screw it up. I'd consider sacrificing the stretchers if they're not too complicated. That way you can have a proper tenon and just have to cut a new mortise. This'll be stronger than a floating tenon or dowel.Also, I always build as strong a possible, because once it's out of your shop (and your control) you never know who's going to put their bowling ball collection on the table or use it as a butt rest!)Good luck!Seth
*Let me suggest that biscuits are a better choice than dowels. Dowels quickly loosen as they dry out. A double row of biscuits will have more longterm strength. Loose tenons are an excellent choice also.
*On the bright side bikeboy, at least you know you make a strong mortis and tennon.
*What about drilling a 1/16" or so hole down into the top of your leg and hitting the back of the mortise (there should be some space back there) and filling with assorted chemicals? I've heard positive things about "De-gloo Glue"(sp?). I've seen it in woodworking catalogs. I'm just trying to brainstorm more before you grab the saw. How would a restorer go about this if it were an old table? Hide glue benefits rise again, perhaps. Reverse the heads on a pipe clamp for a spreader while using a heat gun or lamp to soften?
*Seth and Howard,First, while this project will be leaving my shop, it will not be leaving my home, so I do have a fair amount of control over what goes on it.I'd like to just re-do the stretchers, but frankly I don't have enough clear cherry wide enough to do it. I ordered wood from an online resource, Niagara Lumber. I've ordered from them in the past and have always been happy. This is the first time, however, that I really realized why it's not always OK to get lumber sight unseen. This is the first project where I really needed to have a certain amount of wood that was over 5 1/2" wide. While you usually get wood wider than that from them, you don't always. In this case, I just barely got enough to do the piece once, even though I over-ordered by 20%. Just didn't consider that I might not get very much of the width I needed. I'd order from them again, 'cause their prices are good (I've yet to find anyplace cheap to get decent wood in the MD/DC area) and convenience is unbeatable, but I'll be keeping in mind that I might get all 4" wide stock. I think I might even be able to specify my needs to them, but you just never know.In any case, re-doing is not an attractive option. Likewise dowels are less than thrilling. I can get my hands on a beadlock setup today from a friend, so I'm gonna try that--dual 3/8" tenons should be strong enough.Thanks everyone for your help.
*What about drilling a 1/16" or so hole down into the top of your leg and hitting the back of the mortise (there should be some space back there) and filling with assorted chemicals? I've heard positive things about "De-gloo Glue"(sp?). I've seen it in woodworking catalogs. I'm just trying to brainstorm more before you grab the saw.
*SamF,That's a good thought, but in all it seems simpler may be better in this case--it's just not that big a deal if I lose even as much as 1/2" of depth, so I'm not afraid of going in with the saw. I will, of course, want to err on the site of cutting more off the stretcher than risking hitting the leg, as I think someone showed some concern about.Worst case, this is a learning experience for sure. But I'd rather learn about beadlock joints and get some sawing practice (and maybe learn to fix a hacked up leg) than get a bunch of new chemicals involved.
*If you can get the temperature up it'll move. You might not even have to disassemble the joints, just heat until things become flexible and allow it to reset. If you are going to use a space heater or other device to slowly bring the temp of the thing up, obviously you would have to be very careful and watchful so you don't burn the house down.
*I live near Hearne hardwood, but I think they UPS out a great deal of lumber. Pretty nice stuff, too.610.932.7400So there's another option. I'd guess you could specify nothing under a given size.Glue-ups are pretty stressful, with or without the dry run.
*A loose tenon will be a stronger option than the beadlock joint. the issue with dowels is not that they dry out, but that round joinery doesn't have as much face grain glue surface, so the beadlock is a similar issue...I think this is a valuable lesson about the inherent problem in clamping across the diagonal to bring things square. In the future, try just skewing your clamps a touch. Think of this - a clamp always wants to square itself. So, if you move your clamp (very slightly) into parallel with the longer axis, it will begin to bring it back into square. You have to keep rechecking, though, to make sure not to overdo it, just like when clamping over the diagonal. This way is just quicker, takes less clamps, has less tendency to overshoot square, and you don't risk damaging your corners...SB
*Hi bikeboy this may be a little late for this project but it might help you in the future . I run a small cabinet shop and sometimes people bring furniture for me to repair, the easiest way I have found to loosen glue joints is to use ( vinegar). That's right plain old household vinegar will turn pva (yellow) glue to a rubbery goo that can easily be took apart. hope this was helpful.
*This is slightly off topic but you might want to consider checking with Hearne Hardwoods or Groff and Groff Lumber for cherry in the future. They both have excellent selections (Hearne in particular) and are great people to deal with. Depending on where you're located they may be within reasonable driving distance so you can select what you want.
This forum post is now archived. Commenting has been disabled