Replies

1. 
   KeithNewton | Aug 04, 2006 07:53am | #1

   If you are in the Northern hemisphere, and anywhere near as hot as it is here, and IF you have done a good job of milling your lumber it would probably be OK. However there are exceptions. If you are using a very dense wood that doesn't absorb the water / moisture out of the glue very fast, you should give it longer.

   Even if I know that my edges and everything is nearly perfect, I usually give it longer. If it is with a hard dense, resinous wood, and cold weather, I have been blown away to find some joints still wet after setting over-night.

   Here is a way to test. If you glue up with extra length. Soon after you take the clamps off, cut the extra length off to the finished length, then break the scraps. If it breaks outside of the glue-line, you have nothing to worry about. If it breaks along the glue-line, examine it under as strong a magnification as you have access to. The nature of failure should be obvious.

2. 
   hammer1 | Aug 04, 2006 04:06pm | #2

   If your joinery fits tightly without clamp pressure, you can remove the clamps shortly. I like to wait about an hour. If you have had to put a fair amount of pressure on the glue up, leave it overnight. Drying conditions vary, you are better to err on the longer time side. What's the matter, not enough clamps? Heh Heh!

   Beat it to fit / Paint it to match

1. 
   GotAll10 | Aug 04, 2006 04:11pm | #3

   How did you guess??

3. 
   mike_b | Aug 04, 2006 07:30pm | #4

   I followed the 30 minute clamp (usually longer), overnight dry routine for years. A couple of years ago, I was advised by several pros that much less time is required under normal conditions (temperature, wood species etc.) for yellow glue to dry. I have since jointed and planed glued up panels to final thickness after only 20 minutes dry time. I briefly worked with a guy who routinely had panels dimensioned to final thickness and on the shaper for panel raising in about 40 minutes.

   
   

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   Edited 8/4/2006 12:33 pm ET by Mike_B

1. 
   joinerswork | Aug 06, 2006 07:50pm | #5

   Mike,

   In my experience, a longer dry time is necessary-- not for glue strength, but to allow moisture from the glue to exit the wood along the glue line.  I've ended up with a (very shallow) depression along the glue joints,  when I've been in a hurry to plane and /or sand a top too soon after glue-up.  Usually see this only after the finish is on, in a raking light, when you are delivering the piece :-((

   Regards,

   Ray Pine

4. 
   pcooper | Aug 06, 2006 08:34pm | #6

   I usually let my stuff sit in clamps for a couple of hours to overnight depending on humidity and temperature, but never unclamp after just a half to one hour. I just don't like to risk it not being good enough that quick even though the bottle says so. Oh, BTW, does anybody ever have enough clamps?? I have a wall covered with them and still find not enough of them some days. :-) I just have to work slower sometimes.

1. 
   ronselectrons | Aug 07, 2006 03:14am | #7

   Norm once said, "you can never have enough clamps" and I totally agree with him.  My problem is I try to use clamps in a way they were not designed to work because of my shortage of clamps, or have a couple of 2 foot clamps extending off of a small piece, making it look like some kind of 8th grade woodshop project from h_ll.  There is a sience to clamp pressure also and I have found out the more I think I know, the more I dont know.  Why is that?? 

   Continuing to make small wood out of large wood.

   Ron.

   Edited 8/6/2006 8:14 pm ET by ronselectrons

1. 
   pcooper | Aug 07, 2006 12:33pm | #8

   I'm in the same boat, lots of shavings, and not much wood left sometimes. I made some cabinets a few months back and found out then that my clamps were not all the right kind and size, so I ended up with things made up too. It wasn't pretty but got the job done. Clamp pressure is exactly an exact science, and like you I never seem to know what is enough or too much. Lucky for me nothing has come apart yet but I have had to do extra sanding where I should't have due to clamping without scraps of wood protecting things where I didn't have room for the extras. Trial and error is my method, if it works keep it up until it doesn't work and try something else.

2. 
   forestgirl | Aug 07, 2006 07:54pm | #9

   "or have a couple of 2 foot clamps extending off of a small piece,"  Yep, that's a pain.  I'm going to start using a wedge-type system to glue up these small things.  The clamps are so big and unwieldy!

   I've seen a few different sketches of a wedge-type clamping system, but one of the better looking ones is in this month's Woodsmith magazine, page 6.  It involves pivoting arms and positionable dowels so different sized panels (or whatever) can be glued up, 2 wood wedges to provide clamping power.  Would work for some stuff, anyways.forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-) 

5. 
   BossCrunk | Aug 08, 2006 09:41pm | #10

   If you have to take the work out of the clamps before the next day then you haven't planned your order of work very well.

   Set aside a day to do all the glue-ups your project will need.  Glue them up.  Leave them sitting in clamps until the next day or even longer.  I know, the clamps loosen as the glue dries.  Don't worry about it, just leave them. 

   Go ahead and work the project parts that don't have to be glued up.  I'm hard pressed to think of *an average* furniture project that doesn't have a few day's work, at least, on non-glued parts.

   Glue the panels and let them sit.

   You need to add the rubbed joint with hide glue to your repertoire as well.  Works great on parts 36" or less in length.  No clamps needed.

   Buy some pinch dogs while you're at it.

   I've walked into more than one shop with an incredible array of shiny machines and not enough clamps to build a bookcase.

   You've got to pay to play.

   A clamp inventory ought to cost at least as much as the average consumer-grade cabinet style tablesaw.  If you're serious about woodworking, this shouldn't be a tough check to write.

   
   

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   Edited 8/8/2006 3:03 pm ET by BossCrunk

1. 
   GotAll10 | Aug 09, 2006 07:01am | #11

   Thanks.  What's a rubbed joint with hide glue?

   Paul

1. 
   BossCrunk | Aug 09, 2006 02:21pm | #12

   Hot hide glue has tack or 'suck' as some people call it.  You simply put a board in your vise, apply the glue to the edge put the other board edge on edge rub back and forth a time or two and bam, it's stuck.  Let it sit for about ten minutes then set the panel aside (upright, against battens) to dry.

   Quick and dirty explanation.  Do a search for more info.  You need to start your woodworking library - Google Ernest Joyce....