Glue Up Question

[Ronald Blue]

I need some advice on a project I am currently working on. I am building a hall tree bench for a co-worker. The framework is out of pine. (Not my choice) My question is this. I am almost ready to start gluing it together. It has plywood panels in it as well. I am thinking I should leave the panels floating because they will not change size with the seasons or will change very little and if they are glued in solid it will be a recipe for disaster. Anyone have experience/knowledge of this and if I am correct in my line of thinking? Thanks in advance.





I feel I am a midget among giants when I look at the photos of what many of you do.

[Jamie Buxton]

The answer to this might depend on your design. But consider a specific design, a frame-and-panel door where the frame is solid lumber and the panel is plywood. I glue the panel in. The lumber is not going to grow or shrink in the direction along the grain. It only moves across the grain. Plywood does not move in either direction. If the panel is glued in, it acts as a huge gusset to all the corner joinery, and makes the door enormously stronger.

[Kent A Bathurst]

........... I am thinking I should leave the panels floating because they will not change size with the seasons or will change very little and if they are glued in solid it will be a recipe for disaster...........

As Jamie noted, gluing them in place might be fine - depends on what the design is. OTOH - its pretty hard to go wrong with floating panels - glue/pin/peg them in the center of the rails, and let the rest float. With good joinery in the frame components, it'll be plenty solid enough - by my count, there are slightly less than 19 jillion furniture pieces made this way, and doing well.

[Ronald Blue]

So they will not grow/shrink length ways or in line with the grain? If I understand correctly then it will add tremendous strength to glue the panels in. I just didn't want to have it destroy itself after a year or two of Midwest summer/winter humidity changes.

[David Thompson 27577]

So they will not grow/shrink length ways or in line with the grain? If I understand correctly then it will add tremendous strength to glue the panels in. I just didn't want to have it destroy itself after a year or two of Midwest summer/winter humidity changes.


Correct -- wood expands across the grain, but not along the grain. If you were here in front of me, I'd be holding one of my hands up, and I'd pretend that my fingers were the grain lines. I can make my hand wider or narrower by spreading my fingers -- but I can't make my fingers any longer. Same with wood. It gets wider and narrower, but not longer and shorter.

And yes, if you use a plywood panel, gluing it in does add tremendous strength.