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If I glue up some boards and let the glue dry for say 30 minutes it is then safe to remove the clamps. Then can I add more glue and board and reclamp the new setup. Or will reclamping the partly set glue joints cause problems?
I know I should just wait overnight for each setup but that takes days on complex glue ups.
Bill D
Assuming PVA and raw wood I have routinely moved ahead with sub-assemblies being glued to other parts after 30 minutes to an hour (depending on the weather) for years without issues. I generally use the squeeze-out as a barometer. If the squeeze-out is leathery/rubbery I feel good about moving ahead. I have experienced no ill effects from re-clamping already set but not fully cured joints.
You don't mention what glue you are talking about. Using Titebond I you can't break the boards apart in 10 minutes. There should be almost zero glue left in the joint after that same 10 minutes. So for that glue, you are safe. It would be a very simple experiment to test the theory.
I recall reading that at room temperature, Titebond I will reach 80% of full strength in two hours.
I take my time. A lot of times I'll full assemble, only gluing 1 element at a time. I'll let sit for 4 hours, then glue another element in, rinse/repeat. Why rush? It's taken a considerable amount of time to get to where I'm at already so a little patience costs less here (oftentimes). The same with finish, people get impatient towards the end imho.
Edit: I'm assuming/using TBII mostly
I use Titebond Original and go by the squeezeout. If it's rubbery or hard I will go ahead with the next step. Sometimes this is in half an hour, in the winter when the humidity gets down into the 35% range.
Bill, are you talking about a second round of clamping in the same or a similar direction, or in a different direction? I wouldn't hesitate to keep working after 30 minutes if the clamps would close the first glue joints and the second glue joints. But if they're in different directions and the clamps might put force on the first glue joints, I would let those cure longer before clamping them.
I let things set for a couple hours of using TBII extend or Quick and Thick, then as long as the next set of clamping doesn’t stress the previous I keep going. For pressure I rarely use more than just a hair past finger tight.
OK, something to consider is that IF the previous bond is broken you can not just add more TBII and get the same bond strength, so although I do similar I have also pushed the envelope and had to start over. If the wood did not have any stresses that the clamps had to overcome you will be fine in a half hour or so in dry conditions, maybe a little more in humid weather. TBII is a fairly complicated molecular bond where the wood needs to be in contact with the wood, where epoxy is a mechanical bond so each require different clamping strategy. TB can and should be squized tight, where you do not want to starve an exoxy joint and so use less pressure.
Correct me if I’m wrong but I think the question is gluing different parts of a project. Re-gluing the same seam again, well, I never do that. If it doesn’t work the first time, seems like you need to rethink the process or get new glue.
You are wrong. His question was about taking it out of the clamps early to glue the next step and if that was a problem. If it is a problem and the joint fails and has to be re glued my answer is relevant.Quote:
Originally Posted by Michael Burnside
I said “gluing different parts of a project”. You said “to glue up the next step”. You said “you are wrong”. Hmmm.
The bottom line here is that one can take assemblies out of the clamps after the minimum time period that the glue manufacturer states but those assemblies should be handled very carefully until there is a full cure. There is going to be a judgement call if one chooses to take those freshly glued assemblies and combine them into a larger assembly with glue. For flat panels...less risk, IMHO, as long as clamping pressure isn't excessive and cauls are used to keep things flat. I'd wait for a full cure for assemblies that are not flat panels and also not try to maneuver even a flat panel if it's large until full cure due to the stress that can be introduced as our frail, human bodies have to work hard to move something very heavy. ;)
Yes................. :)