Clamping, excess glue

[Eric DeSilva]

I've tried taping inside corners, wiping off with a wet rag... Neither seems to work particularly well. I saw someone indicate they waited about an hour and then scraped off the excess in glue ups. Seems like a reasonable method, so here's my question... Is it OK to remove clamps after an hour? I recognize there are significant benefits to substantial clamping pressure, but how long do the clamps have to be attached to attain those benefits? I've always left 'em on overnight, but I'm now wondering if I really have too...

[Paul Girouard]

Is it OK to remove clamps after an hour?

I recognize there are significant benefits to substantial clamping pressure, but how long do the clamps have to be attached to attain those benefits?

I've always left 'em on overnight, but I'm now wondering if I really have too...



That depends on what you'll be doing with or to and really what you've glued up.

So lets say it's a edge banded piece of 3/8 x 3/4" lumber EB on a plywood panel . Sure clamp could be removed and some light sanding / scraping to flush up the EB to the panel could take place.

If it a table / cabinet / big panel under some stress joint to joint I'd say no let it sit at least 12 hours.

Then again it depends what type of glue your using, temperature, humidity, etc etc .

Hot dry summer day , 4 hours in the clamps in the sun and you could cut that cure time down.

Scraping glue after about 1 hour is a good idea , just when it's at the gummy stage , chisel or puddy knife and it will sort of roll up into a ball , or pull off like string sort of .

So in short, your question is to broad to answer well as submitted.

[Greg Cole]

When I clamp about anything, I will set it aside and leave it for minumum of 12 hours (I use TB1, 2 & 3 most of the time), and usually leave it over night. I've learned the hard way to leave a clamped glue up alone and don't need that lesson again.:rolleyes:
Some glue mfrs say 30 minutes of clamp time is adequate, but I see nothing wrong with more. And the not stressing a glue joint for 24 hours is a good rule of thumb for me.
The wet rag method is ok for me with tight grain-pore material... walnut, oak and the open grain stuff not so well.
As we say & hear an awful lot... no such thing as too many clamps. Cuals will cut down the # of clamps needed, but they interfere with glue clean up just as the clamps do.....
FWIW.
Greg

[Fyrman Dave]

I just finished up an oak bookcase using Titebond II. I used a rag and toothbrush with excellent results, removing the glue as soon as it was clamped up.
Because of a clamp shortage, I went with the 30 minute minimum to an hour or so with no issues.
Dave

[Frank Drew]

I think peeling the glue off when it's rubbery, if you can get to it, is the best method; sometimes the wet rag method leaves behind a trace smear that will show up when you put the finish on.

I agree with Paul that the kind of glue joint, and, importantly, the kind of glue used, will determine how long the clamps need to stay on; a mortise and tenon joint, for instance, doesn't usually have a lot of force wanting to open it up, so the clamps can come off fairly soon, say after an hour or two. A complex bent lamination using plastic resin glue, on the other hand, should stay under clamps for probably 8-12 hours, depending on the ambient temperature in the workshop.

[NICK BARBOZA]

I'm with Paul on clamping time. depends what it is im glueing up... typically 3-4 hr min on a larger glue up, but edgebanding, maybe 1 hr. also i pretty much only use TBII.

as for glue removal, i usually use a wet toothbrush and "scrub" then wipe down with a dry, clean rag. light sanding after that gets rid of any residue. works well on most cases for me.

Cheers,
Nick

[Christopher Foote]

Prefinish your pieces before glue up, whatever squeezout you get won't stick. I use an old plane blade to pop off the dry glue. It's hard to resist the urge to assemble and glue up a project prior to finishing, but you'll save a lot of needless fussing if you do.

christopher

[Paul Gatti]

I just finished up an oak bookcase using Titebond II. I used a rag and toothbrush with excellent results, removing the glue as soon as it was clamped up.
Because of a clamp shortage, I went with the 30 minute minimum to an hour or so with no issues.
Dave

+1 I use a tooth brush with plenty of water to remove the glue as soon as I'm done clamping. I then use a rag to wipe off the excess water. As we all know, any glue left on the wood will interfere with the finish. My father has been a professional cabinet maker for nearly 50 years and this is how he does it, but I'm sure it's not the only way.

[Tom Esh]

Prefinish your pieces before glue up, whatever squeezout you get won't stick. I use an old plane blade to pop off the dry glue. It's hard to resist the urge to assemble and glue up a project prior to finishing, but you'll save a lot of needless fussing if you do.
christopher

BINGO!
And for those who find delaying the satisfaction of seeing it assembled just too intolerable, take some digital pics of the dry fit and make it your wallpaper or screensaver.

[Eric DeSilva]

That depends on what you'll be doing with or to and really what you've glued up.

Good point. I was thinking of a specific glue up, but my question was somewhat more generic--do you need to keep the clamping pressure on until full cure to get the benefits. Sounds like the answer is no, although the amount of time is variable...

After posing the question on SMC, I did what I should have done before--d'oh! I went to Titebond's site. Here's what they say:

For most of our wood glues, we recommend clamping an unstressed joint for thirty minutes to an hour. Stressed joints need to be clamped for 24 hours. We recommend not stressing the new joint for at least 24 hours. For Titebond Polyurethane Glue, we recommend clamping for at least forty-five minutes. The glue is completely cured within 6 hours.

So, sounds like I could probably remove the clamps after an hour--the joint that I'm talking about is a face to face long grain glue up that isn't under stress--and peel off the residue then.

The pieces are pre-finished and, while glue doesn't stick to the finish as well, it still sticks pretty durn hard if you let it fully cure...

Thanks for the responses!

[Cliff Rohrabacher]

Gummy or hard = no matter
So you don't lose anything by waiting.

It's when you mess with while it's still liquid that's the problem.

[Tom Veatch]

My technique is to leave the clamps in place until the glue is completely set. I picked up an old Stanley #90 several years ago that, used in chisel plane mode without the top/fore piece, cleans out the dried glue like it was never there.

[Brian Penning]

Prefinish your pieces before glue up, whatever squeezout you get won't stick. I use an old plane blade to pop off the dry glue. It's hard to resist the urge to assemble and glue up a project prior to finishing, but you'll save a lot of needless fussing if you do.

christopher


Nah!..That wouldn't work for me cause I'd end up finishing the pieces in the areas to be glued. Sure I could tape the areas I guess(too much trouble) but the finish would leak under the tape for sure.

[Peter Quinn]

First step in my process is to use less glue. If you get squeeze out all over the place on joints that are difficult to clean, you have used too much glue. I'm looking for a hairline on most joints. For cope and stick type doors, I mark both sides of the work at all intersections with slight pencil lines and stay just back from the intersection, keep the glue film thin and even. Rarely any clean up required.

For minor squeeze out I use a glue brush trimmed with scissors to slightly less than 1/4" and plenty of WARM water. The short brush is stiff, doesn't spread a shower of glue polluted water on the work, and is fine enough to be agile and reach tight spots. The plenty of water part is to rinse the brush and clean out the corners without creating a container of glue sizing that will be transfered to the work, sealing the grain and making finishing a big problem. I keep the brush damp, not soaked and dripping, and dry up as I go with a clean or slightly moist rag.

For panel glue ups or such which are easy to sand or scrape, I wait until the glue is gummy and stiff then scrape it off with a putty knife.

As far as clamping time, the only thing I have ever let go over night is face laminations (including bent laminations) or hard to glue woods like teak or cumaru. If your assemblies are under so much tension that you need to leave clamps on for 12 hours then you may want to work on that. If you regularly use clamps to tweak work in an attempt to over come inaccuracies you may want to work on that too. Easier to remake a few parts than to remake a whole piece.

This advice is for PVA glues, for other glues get your tape out. Epoxy, plastic resin glues and polyurethane glues are very difficult to clean when wet and even more difficult to clean when cured. Again, use less glue if major squeeze is a problem.

[Chris Padilla]

PQ's method above is pretty much what I use (toothbrush, rag, cut-down acid brush and warm water). You just have to learn to put the right amount of glue on and that is purely by experimentation and experience.

There are ways to prevent squeeze out depending upon the joint. Some examples:

I NEVER glue the shoulders of a M&T joint as I don't see the point because of the face-grain to long-grain. Just glue the tenon and mortise: that is where all the strength of the joint is anyway. Think about it, not everything always needs to have glue on it!!

If there is room, you can saw a small shallow kerf into the wood that will catch the squeeze-out and fill this small channel instead of leaking out on you. This one is more difficult to implement because it only works on a few type of joints.

Clamps typically stay on overnight for me but it depends if I have time and enough clamps but I'm a hobbyist...there's always the next day to remove the clamps: no hurry.

[Peter Quinn]

I read Chris's post and it occurred to me that my opinions regarding clamp times are largely driven by my experience in a commercial mill work shop where there are walls of clamps and yet still never enough. With ten guys competing for clamps and the boss clamoring to meet dead lines you are often forced to understand 'Minimum' allowable clamping time to free up the work for processing and the clamps for additional use.

Truth is I subconsciously time my whole day so that I clamp the long glue ups or complicated assemblies near quitting time when possible. And the occasional slightly out of square piece that needs a little tweaking and a lot of clamps always gets clamped near the end of the day.

So if its a hobby and you have limited clamps many glue ups don't need as much time as people often want to give them. But if you have enough clamps, and you are the boss, and you decide when its quitting time, no production schedule to meet but your own, there is no Maximum clamping time and no harm in being cautious and letting things stay in clamps over night. I'd still try to clean the joints immediately and accessible squeeze out on long grain joints when its not rock hard, like an hour later over a beer (not at work!).

[Doug Shepard]

I think peeling the glue off when it's rubbery, if you can get to it, is the best method; sometimes the wet rag method leaves behind a trace smear that will show up when you put the finish on.
...


That's pretty much my modus operandi, but the work is usually still left in the clamps when I do it. There's usually some tool that's able to do it with the clamps in place if they're a bit in the way. IMHO PVA glue+water=glue sizing and it not always easy to spot until too late.