Woodsmith article on panel glue up

[Keye]

Anybody read this yet? I found it interesting that the article recommended putting glue on only one edge of the board. When I first started trying to learn woodwoorking in the mid 90's one of the first things I learned was to place glue on both edges.

Any thoughts or opinions, like no one every has an opinion:rotflm:.

A couple of years ago I went to a small cabinet shop and asked it they would like to have free grunt work for a few months. Thought I might learn something. There was an elderly German cabinet maker working there. He apprenticed in Germay (six years I think he told me). One day he asked me to glue up some panels for him. Shorly after I started working on this he came over and told me to only put glue on one edge and made some mumbling comment about what he thought about modern woodworkers. He also told me to crank down as hard as I could on the clamps. He then came over after I was finished and cranked down on the clamps some more. Forgot to mention that while I was pulling the boards together he came over with a hammer, a regular hammer, and beat the heck out of the boards to flatten them out. I just new the panels were going to be full on major dents. There was not one dent. I still have no clue how he did this.

Anyway I was just wondering what you guys might have to say about glue on only one edge.

 

[cpowell]

For M&T joint, glue on tenons and in mortises...both pieces. Gluing solid wood to ply, glue on both edges. False tenons, glue on both edges. DTs, glue on both edges.

For panels, I set up the clamps (K-body) and dry clamp the panel to check the clamps are where I want them and verify the fit. I then back off the clamps and turn each board up resting on bottom edge and apply glue to ONE side only. I know the amount of glue is right if I get droplets for squeeze out, not full runs. I clamp from one side to the other, flattening the panel if an edge slips up. After a minute or so, I gently turn the clamp handle a little more - again, all the way across the glueup. I will apply force until the joint line disappears - no more. I think the minute or so that I wait before applying additional pressure is enough to fully coat the "dry" edge. I usually wipe down with a damp cloth during this waiting time...damp is key, no excess water to dilute the glue.

So, I believe one edge is just fine. I don't agree with the "clamp the heck out of it" approach though.

I have coaxed a board down using a rubber mallet but do that before I reach full clamping force. I accept that a panel glue up will not be perfect and will require some sanding/scraping for final flattening.


Chuck

 

[DaveO]

I only apply glue to one edge of a panel glue up, and spread it out with an acid brush. That has always provided me with enough glue to get a good but minimal squeeze out line. I clamp with Bessy and generally crank the clamps down as hard as I can. There has been several articles out on how much clamp pressure to apply, and most have found that normal woodworking clamps barely provide enough force.
I have never had a panel fail yet.
Another trick that I learned is to stack your panel boards on end. If they can stand up in the stack your joints are good and square.
Dave

 

[BobN]

Guess I'm pretty much like your old German cabinet maker. I put glue on just one edge, than I clamp then snug. Next I take my hammer and a small block of wood and beat the panels flat. Next I tighten the clamps as tight as I can get than. After the panel has set for about 40 minutes I take a sharp chisel and remove the squeeze out. Never had a panel fail in 40+ years of wood working. Also have a very minium amount of work to do with a hand plane to get a truly flat panel.

Bob

 

[WoodWrangler]

Well, goes to show what I know ... I just did this again today and I glued up BOTH sides. I think I'll save some time and effort next go around with a ONE side glue-up on the panels. :saw:

 

[John Reeves]

I have done this (gluing) both ways and I do not notice a difference.

I usually use my pipe clamps as you can get more clamping pressure from them. Why do I need more clamping pressure you ask? Because I can not get a straight edge on a piece of wood (must be my joiner!!!)

 

[Joe Scharle]

My proc is :
glue one edge
slip two adjacent edges together to get full edge coverage
clamp down hard
release slightly
hammer down on a block
clamp down hard

 

[Nativespec]

I like to use a glue joint bit-it is a bit of work, but much less likely to fail.

Depending on what my glue up is, I will either use cauls or some old marine batteries to flatten the work.

I don't see how it matters if you spread glue on both sides as long as you have enough glue.

I have heard advice against over-clamping since you may be squeezing out all of the glue.

I don't worry about hammer marks (I use a rubber) because I will have to take down the surface anyway.

David

 

[SkintKnuckle]

Guys! I thougtht I'd chime in with a few comments.

First off, about the only benefit you'll get from putting adhesive on both pieces to be joined is that you can get by with a little more open time. For instance, if you laying up a really large piece and you need a little time before getting the clamps tight, dual application will keep the glueline wetter longer until you get everyting tight. The only real exception would be if you're working with stock which is exteremely absorbant, like maybe some really dry white pine, or similar wood, in those cases applying to both surfaces will help. Otherwise, if you're applying enough adhesive to give you squeeze out when you tighten the clamps, you'll have enough. If you're not getting squeeze out, you're not applying enough adhesive.

With regard to clamp pressure, the amount of pressure required actually varies depending on the adhesive being used, some types like the PRF waterproof types MUST have really tight clamp pressure. Since most of us use PVA types they're a bit more forgiving, but you really want to keep the glueline as tight as possible. I don't have as many clamps as Norm Abrams, so I try to compensate with hand tightening as tight as possible. If I'm using anything softer than maple, I'll back up the clamps with a sacrificial piece to prevent dents, if that gives you an idea on how tight I'll go. There are times when commercial shops with hydraulic equipment have clamp pressure so high that they'll actually press the adhesive from the glueline, but in a home shop, I don't think it can be done with handclamps. Tight gluelines means strong joints.

Hope this helps

 

[WoodWrangler]

To help with the good glue up and few clamp problem, I have been using the BowClamp (http://www.bowclamp.com/) product. I first heard about it on here, and decided to pick some up ... worth EVERY PENNY.

And yes ... seems silly to pay so much for what is essentially "wood", but it's been a good investment since I could spend that much just for something else made of plastic!

 

[pslamp32]

I use my Domino on all panels and reference off the 'show' face of the boards. This way I know that that face will be virtually flat. I have been gluing both edges but may change that from now on. The Dominoes do such a great job of alignment that I didn't realize this was ever an issue since it was one of the first tools I bought.