Plywood glue up question

11/6/18, 6:28 PM #1

Tom Norton
Guest

Plywood glue up question

Tom Norton

As I move forward with the plan for garage doors I have a question for you folks! My core will be a frame with 1/4" ply glued to both sides with polystyrene insulation in between. So here is the question. The exterior will be a cedar rail & stile with the fields being 3/8" ruff sawn ply glued to the 1/4" core. It will be run vertical where as the core is horizontal.

Am I setting myself up for a problem?

Re: Plywood glue up question

11/6/18, 10:33 PM #2

Ellis Walentine
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8,683 posts

Registered: 11/26/00

Gonna speculate

Ellis Walentine

Questions like this always raise red flags about "balanced" construction, although this isn't a typical veneering situation. My concern would not be about grain direction of your two plywood layers, but about whether both sides of this door are the same, i.e., will there be a 3/8" layer glued onto the inside core as well? If not, your construction needs to be robust enough to counteract any warping or stressing you are setting up by the unbalanced construction. I can't think of any way to calculate this likelihood, unless you want to try making a sample. Keep in mind that, with a garage door that has sun exposure or differential temperature conditions (large difference in indoor vs outdoor), you need to consider these factors in your testing as they could affect the moisture exchange or deforming tendency of this construction.

Sorry, can't be definitive. My hunch is that you will be able to get away with your plan without major problems. I just wanted to suggest that you consider things that could be factors. If you can do this without actually bonding the two plywood layers together, I'd feel more confident about it.

Ellis

Re: Plywood glue up question

11/6/18, 10:52 PM #3

Tom Norton
Guest

Re: Gonna speculate

Tom Norton

I could pin/nail it around the perimeter but some of the "fields will be 20"x 48".

Maybe I will redesign it eliminating the 1/4" ply and just use 3/8" on both sides.

Re: Plywood glue up question

11/8/18, 2:50 PM #4

Kneale Brownson
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1,031 posts

Registered: 8/1/07

Re: Gonna speculate

Kneale Brownson

I've had three older wooden garage doors over the years, all built as frame and panel designs. The panels were all single layers of approximately (never took one apart) 3/8 to 1/2 inch in framing that is 1 1/4 inch material.

If your goal is to produce an insulated door, why not just glue insulation to the inside?

- - -

I’m a fairly spry 82-year-old who had been a reader/participant at WoodCentral since the demise of Badger Pond. I started visiting BP to learn something about finish for a project I’d completed and became hooked on internet forums as a way of increasing my knowledge about all sorts of topics. I have been a moderator for a couple other forums on subjects I enjoy. My interest in woodworking began in the early 1970’s when my wife and I had contractors add to our house near Traverse City, MI, and I ended up doing the trim work to reduce mounting costs. I had no tools. I bought a P-C skilsaw, hammer, screwdrivers and one of those wooden miter boxes with a backsaw. I made trim for windows and doors from one-by lumber and started my woodworking career. At the same time, I started a 50-year career as a ski instructor. I got onto the night shift at a mental hospital so I could ski days, and spent my 30s and 40s with that schedule. I eventually replaced the PC-upside-down-in-a-board with a real table saw and began the purchase of enough equipment to fill a jam-packed 40-foot shipping container we used after we sold our property in Michigan. The ski instructing had taken us to Colorado and we were spending too much on maintaining utilities for two homes. A couple years ago, the dozen years spent at 10,000 feet of elevation was making my body produce too many red blood cells, so we had to leave my “forever” home in the mountains and we moved back to Michigan. Now I have to find myself a shop space for all those tools in the container.

Plywood glue up question

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