glue-up/clamping question; could use help ASAP, thanks!

[Mike in Mystic]

Hi everyone,

I'm about ready to start jointing and planing, and then edge gluing several panels for a chest of drawers/changing table that I'm building. The wood is ash, if that makes any difference.

My question is that I only have enough clamps to probably glue up 2, maybe 3 panels at once (I have 7 total that I need to glue for this project). All of the panels are meant to be 3/4" thick and the rough lumber is somewhere around 7/8" to 1". Due to the large number of boards involved (most of the stock is ~5-6" wide and I'm making panels of 22", 15" and 23" wide and 48",

49", 27" and 23" lengths) I would prefer to do all the milling for these pieces at once to make sure that they all are exactly the same. This is mainly a concern with the thickness planer, I think.

The only thing is, I've surfaced some ash in the past and had some minor cupping occur, so I was thinking maybe it would be better to only surface and glue the boards that I'll be clamping right away.

The humidity isn't too high today, but in the next few days we're supposed to get rain. So, I'm in a bit of a conundrum.

If anyone has any tips for this issue, I'd appreciate it.

Thanks!

Mike

p.s. The "get more clamps" tip is one I already have thought of, but can't seem to find the $$ to make happen right now.

[George]

What he said. If you're really worried, stack all the unclamped pieces together and hold them in a tight bundle with cauls and C clamps.

I think the warning about gluing fresh really means don't let it go for weeks and let the wood oxidize for best adhesion.

[Lenny]

[Preston Andreas]

Also, you might joint and plane to about 1/8" over final thickness, then sticker and let it adjust for a couple of days. Then as close to glue up as possible, joint and plane again to final thickness. This helps reduce warping.

I too am in the habit of gluing up panels or partial panels a little thicker than final thickness and only as wide as my planer will take. I then run the panels through the planer to final thickness and then glue up any partial panels for any wider panels I need. I also leave about 3" extra on either end for snipe.

[Mike in Mystic]

Thanks for all the tips and suggestions. I think the idea of gluing up just shy of the capacity of my planer makes sense. I ended up gluing up 2 of the large panels yesterday and had to leave it at that due to other obligations. I'm annoyed, because one of them seems to have developed a small cup almost right out of the clamps. Aaarghh! I really get confused by this stuff. I had to use 5 boards to make the panels (each was the same dimension). All of the individual boards were flat and square. So, why would one of the glued panels cup and not the other? I did the alternating growth rings thing. Just leaves me scratching my head.

Mike

[George]

Uneven clamping pressure can cup a glueup, too. You want the "draw" right through the center of the glueup. Get high or low, and you can induce cup. One of the best arguments for a big, flat clamping area rather than some ad hoc"hang the freshly clamped end over this" while working on the next....

obligations.

[Mike in Mystic]

Well, I used bessey k-bodies for the entire set up (5 total for each panel), which should minimize this, right? I made sure to tighten the clamps slowly and evenly, with 3 on the bottom and then adding two more on top, alternating positions. Still, I see what you mean, but I don't anticipate getting any more space to accomodate a nice glue-up table, which is probably what I need. *Most* of the time I am pretty successful at these things, but there are times like this when I'm not. I guess I'm still going through the learning curve and haven't entirely figured out where my technique/procedures are not being done just right so that I can avoid these problems.

Mike

[Wolfgang Jordan]

If you leave a panel on the workbench, it can cup because of unequal moisture exchange with shop air. This is reversible, but can be avoided by stickering the panel.

Wolfgang

[Trent©]

Are you running the edges thru a jointer, Mike?

Have a nice week...

Trent

Follow Joan Rivers' example --- get pre-embalmed!

[Trent©]

Give some thought to making a glue-up jig, Mike...then store it away when not being used.

Have a nice week...

Trent

Follow Joan Rivers' example --- get pre-embalmed!

[Lew Hodgett]

I choose to cut to the chase.

Joint the edges of the boards, leave the flats rough, glue up as req'd.

Throw the rough blank in the back of the car/truck, whatever, and head for the nearest commercial job shop sanding facility.

1/2 hour and $20-$30, you have a flat sanded top.

Most shops are limited to 48" wide tops.

HTH

[Mike in Mystic]

Yes, of course I am. I flattened the faces and one edge on the jointer, thicknessed the planks at the planer and then squared the other edge at the table saw. Nothing mysterious about that. But, obviously, there is something I'm not recognizing in certain glue-ups which is leading to the cupping problem. It isn't chronic or anything, but in certain discrete cases it is a real pain.

[Lenny]

FWIW One thing I like to do when jointing pieces for edge gluing is mark the face that is against the fence with an x. Then when gluing up I alternate the pieces so the edge with the x up is going against the edge with the x down. This adjust for any minor discrepancy of the fence being a perfect 90 degrees (the old equal and opposite angles thing from Geometry class). Of course it takes a little planning if your concerned with alternating the annual rings but a few marks as you match up the grain etc. should keep everything in order.

Lenny

[Mike in Mystic]

That's a very good suggestion, thanks Lenny.

Mike