Last night I got a phone call I had to take halfway thru a glue up of a Pembroke table. I’d already applied Titebond II to all the mortise and tenon and dovetal joints and had started the assembly. I took apart the side I’d just slipped together and wiped down the mortise and tenons with water and paper towels.
There is a glaze of glue film on the tenons, the sides of the mortises, and on the dovetail and socket. The joints felt too snug this morning to re-glue as is, and I have no idea if they’ll still stick. What can I do now? Can I lightly shoulder plane some of the glue off the tenons to try to get a fit? Would sanding the dovetail be okay, or do I have to remove the glaze from both surfaces for the glue to still adhere properly? Would changing to an epoxy or some other sort of glue be in order?
If I am completely screwed, I can fill in the mortises, cut off the tenons, re-cut the mortises, and make some loose tenons, but I’d rather not go to that extreme if I can avoid it. I’d hope to start finishing this weekend.
While I am asking questions, I cut an elliptical top, just a shade over 3/4″, about 25/32″ was as thick as I could mill the wood, and am open to suggestions for an edge treatment.
Replies
jj,
Use a sharp chisel and slice off as much of the glue without removing wood . Score some marks and lines to rough them up and re glue , you should be fine .
like you I also need a headset I could wear to talk and work
good luck dusty
I just had a similar problem. I used a scraper to remove the glue from the joint. I made a scraper from a cheap chisel to clean the mortise out. I just burnished a hook on the end. The glue came off easily. Just use a light touch.
Len
"You cannot antagonize and influence at the same time. " J. S. Knox
Thanks guys, I had nioghtmares of having to start over with new M&T joints.
JJohn,
PVA glue doesn't adhere to PVA glue.
Chris @ www.flairwoodwork.spaces.live.com
- Success is not the key to happines. Happiness is the key to success. If you love what you are doing, you will be successful. - Albert Schweitzer
That's what I was afraid of. I had a pretty tight fit prior to my first assembly attempt.
What if I shoulder plane the tenons back to bare wood and use an epoxy? I planed one of the tenons this morning to how much it would take to fit. I took about three-four fine shavings from each side of the tenon to get back to bare wood. I did not try to force it into the mortise because it was too snug a fit from my limited experience. I think another shaving or two on each side would give me a tight enough fit without doing anything to the mortises except cleaning up a glue drop or two. That still leaves the glue glaze in the mortise.
john,
Try to find that article I was referring to if you can. It offered several alternatives, one of which was a solution of warm water and vinegar. I think there was also something about using epoxy too but don't recall the details.
I can go back to it tonight and give you the details tomorrow if that works for you.
Regards,Bob @ Kidderville Acres
A Woodworkers mind should be the sharpest tool in the shop!
Thanks, I'll try to find it before I do anything too rash.
Addendum: I found it. There is no easy answer. The yellow glue to yellow glue will not work. I could use epoxy, but it would make future repair almost impossible. I think I had only applied glue to the side apron tenons and their mating mortises, so I'm thinking of recutting the joinery as a best solution.
I'll plug the mortises, then re-rout them a smidge larger for loose tenons. I have too much work on this table what with cutting an ellipse, making the swinging hinge leaf supports, and cutting the rule joints, not to mention fine tuning the rule joint hinges a couple of times, to screw it up with a crappy glue fix. I figure if the table base is a 1/4" shorter than orignially planned it won't be too big of a disaster.
Edited 5/15/2008 4:16 pm ET by jjohn83
Try to keep it simple. The tenon shouldn't be a problem. If you feel the fit is to loose then glue shims to the face and use a shoulder plane to get back to the correct thickness. If you chisel and scrape the mortise clean and find it is a little to big then gluing shims to the tenon will also correct the problem. If you really aren't happy with the results. You could make the joint a floating tenon.
My God Father once told me, "Sometimes it's how well you recover from a mistake, that shows how good you are." I'm sure you are going to do fine.
Len
"You cannot antagonize and influence at the same time. " J. S. Knox
You might consider roughing them up with sandpaper, removing as much of the dried glue as possible, and then using hot hide glue. Works as a gap filler and is eminently suited for M&T joints and repairablity. Many a guitar neck has been re-glued with HHG and are still going strong after repeated re-assemblies.
Mike HennessyPittsburgh, PA
John,
I found the article that I was telling you about. It was in the Q & A section of FWW #120, Removing PVA glue, to wit:
The writer of the letter wanted to know if there is a solvent for PVA to remove glue once the joint has dried.
To paraphrase Chris Minick's reply: For all practical purposes, there is no solvent for dried PVA glue. A methylene chloride-based paint stripper will dissolve dried PVA glue. Unfortunately, in addition to the methylene chloride, these strippers also contain wax that could cause further problems or prevent you from being able to reglue the joint. Laquer thinner, acetone and methyl ethyl ketone (MEK) will soften dried PVA glue, but none is a true solvent. You could use one of them, and then sand the pieces that make up the joint, but you'd compromise the fit of the joint.
A consensus of friends made the following recommendation: Once the joint is disassembled, scrape as much dried glue from the wood surface as possible without destroying the wood. Then wrap the joint with a water dampened rag for a few hours. The residual dried glue will absorb the moisture and turn white and spongy. Scrape off this whitened glue and let the wood dry. After the wood has dried thoroughly, reassemble the joint with hide glue.
I have had success in my shop regluing joints that were initially assembled with PVA glue by using quick-set epoxy. The procedure is simple. Scrape off the dried PVA glue, apply the epoxy and reassemble the piece. Keep in mind though, that all glued joints will fail eventually. When this epoxy-repaired joint fails, subsequent repairs will be extremely difficult, if not impossible.
The above suggestion(s) to use shims as required to tighten the joint would also be appropriate if necessary and you have matching stock to prepare the shims from. There have been many posts here in Knots that have indicated success with this method and may be required in your application. If you do in fact decide to use shims I would use hide glue for these, not PVA.
Hope this helps,
Bob @ Kidderville Acres
A Woodworkers mind should be the sharpest tool in the shop!
I would definitely hit the tenons with a shoulder plane, pare a little from each mortise, and glue patch to each cheek of the tenons to make up the difference. That should get you a nice tight fit with a good glue bond.
Edit: guess I should've read the previous post. This advice was already given -- oh, well.
Edited 5/15/2008 10:40 pm ET by pzaxtl
John,
If you plan on trimming off the glue, why not trim both the mortise and tenon to remove the glue? If your tenons end up undersized (or your mortises oversized), add a scrap of veneer or two. If you're concerned about the holding power of the glue, why not try drawboring?
Chris @ http://www.flairwoodwork.spaces.live.com
- Success is not the key to happines. Happiness is the key to success. If you love what you are doing, you will be successful. - Albert Schweitzer
Edited 5/16/2008 1:44 am by flairwoodworks
That's amazing, I was just reading an article about this very problem in an old FWW. It was in Methods of Work I think. I didn't take note of which one but it has a pic of Joseph Beals (I think) and an article about making solid wood doors in it.
Sorry I can't be more specific.
Regards,
Bob @ Kidderville Acres
A Woodworkers mind should be the sharpest tool in the shop!
John:
Might I suggest that next time turn off your cell and don't answer the phone! A glue-up is one of those activities that cannot be interrupted.
Good luck!
Hastings
PS Disregard if you are on-call, i.e., surgeon, firefighter etc, etc.
PPS Would the world have ended if you hadn't answered the phone? Because communication is cheap and easy, we got unlimited amounts of it and so most of it is just bullsh1t when really come down to it.
Thanks for all the great suggestions. Since I only had four tenons affected, last night I recut the mortises a little larger from 1/2" to around 9/16", pared down the sides of the tenons to about 3/8", then glued thin slices of cherry to the cheeks to make them 5/8" or so.
This morning early, I planed the tenons down to fit the new mortises. Everything went together square and mostly flush. There are a couple of high spots on the aprons where they meet the legs that will need a few passes from a smoother, but nothing that will take more than a minute or two to make a flush joint.
I guess I had less than 45 minutes extra work altogether. Probably less time than some of you guys took to respond. thanks again for your help.
John,
I'm curious as to what/how you resolved the glue removal process and what glue did you use for the repair? Also, were you able to take a look at my response from the FWW #120 Q & A?
Regards,Bob @ Kidderville Acres
A Woodworkers mind should be the sharpest tool in the shop!
Yes, I found the piece earlier in the day and appreciate your posting it again. It was very helpful and helped me change my mind about an easy fix. In fact all the advice was educational.
After reading that the second time, I decided to re-do the entire joint. I removed all the glue and the wood it had soaked into on both parts. Last night I planed the 1/2" tenons down to around 3/8" and glued some thin cherry offcuts to the cheeks which left them around 5/8" thick. Then I took a chisel and widened the mortises to a little over 9/16". This morning I re-planed the tenons back to a snug fit in my new mortises and glued it all up, nice and square.
I used yellow glue on both the tenon cheeks and the M&T joints. I had just the four tenons on the side aprons that were affected so it only took a little while to repair. The only problem I had, and I just checked it again, is that the apron on one side is a little proud of the legs. It should not take more than a half dozen swipes with a smoothing plane to make it flush.
Watch the table collapse when the first lamp goes on it, but I feel the M&T joinery is pretty solid and should not be a problem. Now I just have to figure out an edge treatment for the top before tonight, because I hope to get it out in the sun tomorrow.
Thank you again for all your help.
Bravo John,
It sounds like you were successful with the repair. As you may know it has often been said that the mark of a true craftsman is in his ability to recover from a mistake. Good on ya.
Now don't forget we all would like to see the finished project.
Good show mate,Bob @ Kidderville Acres
A Woodworkers mind should be the sharpest tool in the shop!
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