glue ups

[tetsuwan]

Hi all,
I've got to make a bookcase for my mother-in-law, and she'd like to have it 12 - 13" deep. Any affordable wood that I can find locally doesn't come in anything near this width, so I've resigned myself to doing glue ups with 6" wide stock. I've never tried a real glue up before and I'm thinking that doing a little tongue and groove thing to reinforce it and then I'd run the result through my planer. Any thoughts on this? Am I way off the mark? Any tips or tricks I should be aware of?

thanks,
jb

[LCHIEN]

Nothing wrong with T&G but probably biscuits and glued joints will probably be way strong enough.

[drumpriest]

Actually, edge glue on long grain would be plenty strong enough alone. The biscuits will help with alignment. I would think that the tounge and groove would also help with alignment.

if you are gluing without biscuits or t&g then the only trick is alignment without such help. In that case I'd glue it up on a flat surface, and clamp downward as well as together.

[Tom Hintz]

A tongue and groove joint is a good choice for a couple of reasons. It certainly will help with alignment, if you get the tongue and groove centered perfectly. It also increases the glue area substantially, making it very strong in both pulling and shear directions.
If youv'e not make this joint before, I have a story at the link below that speaks to centering a tongue and groove. It's easy, especially after you see it done once or twice. If that might help, take a look.

http://www.newwoodworker.com/bldtgdoor.html

[monte]

I'd use bisquits to edge join your lumber. Makes a strong joint and the bisquits help with the alignment.

[Pappy]

No matter which method you decide to use, be sure to scrape off any glue squeeze out before sending it thru the planer. Dried glue can screw up your knives.

[DonHo]

Don't know what kind of case you have in mind but you might think of using 3/4 ply with hardwood front edge to hide the ply edge and add strength too.

DonHo

[Mainemarc]

quote:Originally posted by tetsuwan

Any affordable wood that I can find locally doesn't come in anything near this width, so I've resigned myself to doing glue ups with 6" wide stock.

Hi jb:

Even if you could afford 13" stock, it would likely warp anyway, unless you got quarter sawn stock.

I think the most compelling reason for T&G or biscuits is alignment, not strength. I'm with Drumpriest that a well-done edge to edge glue up is very, very strong.

Tips? Obviously, oppose the growth ring orientation on adjacent boards to minimize future warpage.

Make sure you have plenty of clamps and cauls, and do a dry run of the clamp up before applying glue. (This last point cannot be over-emphasized )

Unless the pieces are very accurately edge jointed, you'd better have pipe clamps, sash clamps or something else that can exert a lot of force to bring the edges together. Don't trust lightweight bar clamps or quick clamps on exerting enough pressure.

Have wax paper and shims handy as you'll probably have to shim between the clamp bars and the boards to get vertical alignment and eliminate bowing as you crank down on the clamps.

Less is more as far as glue goes, but you'll get squeeze out no matter what. With all those clamps in the way, I think it's best to wait until the glue dries before removing the drips.

[AAJIII]

DonHo has the right idea, IMHO you should use 3/4" furniture grade plywood and then apply a hardwood face frame to finish it off. This method will make the unit very strong.

[tetsuwan]

thanks for all the thoughtful replies. Now if I can just figure out what a Caul is, I'll be in business.

jb

[Pappy]

A caul is nothing more than a board used either to spread the presure of a pair of clamps or to clamp against the face of a glue up to keep it flat while the glue sets.

[gmack5]

If you decide to use "cauls" be sure to WAX them to keep the glue from sticking to your work-piece, either that or use WAX PAPER between the cauls and your work-piece.

I'm also with DonHo, Hardwood faced Plywood and edge banding, or a Face Frame, is a much better solution.

[Black wallnut]

6" may be on the wide side for glue-ups depending on the stock you choose. You may have less cupping if you rip the 6" boards in half then glue them back together alternating the growth rings. If you get lucky and find quarter sawn stock then this will not be as critical.

[jnesmith]

I don't think T&G or biscuits is necessary. Here's a pic of a glue up using cauls.





I agree that good ply and hardwood edge banding would be another way to go.

[tetsuwan]

Thanks again for all the help. I'm thinking of using Ash, which I can get at a more affordable price. The last time I checked, I could get boards around 6" or less in width. The reason I want to do this as a glue up is that it's something I've never tried before and should probably get it out of my system now, nor do I want to have to wrestle 4'X8' sheets of plywood across my BT, or borrow someone's pickup to bring them home in :-)
The photo of the glue up with cauls really helps too - I wasn't sure what I was going to need, but it looks like some 2"x4"s and clamps will take care of that.

cheers,
jb