The sawdust is starting at last

[Kody]

I bought all the wood to now start working on the sides and the roof. I have 8 sheets of of premium grade 1/8" pine ply that is beautiful quality. It actually measures a consistent 0.137" in thickness and its 4' x 8'. Wow! What a super find to discover this in this horrible metricated land. The "normal" junk on offer is the 3 mm rubbish that measures only 0.118". I now have a question.
The sides will be made from 1/8 ply glued to a framework of 3/4" x 1 5/8" (actually 1.65") and 2 1/2" wide timber. What glue do you fellas use to glue the frame/sides together? I bought some Titebond for the floor assembly and the glue was just enough in volume for the job. I am now buying some more but there's a problem. The Titebond glue was "Titebond 111" and the bottle stated "Waterprooof - Superior Strength, outperforms all other wood glues, longer open assembly time". I discovered in the FINE PRINT on the back of the bottle the words - "Not for structural or load bearing applications".
I wanted a glue that has a longer open assembly time which is why I bought the "Titebond 111", it allows 10 minutes to assemble the joint. What glue/s do you use for gluing the ply and framework together?
How do you spread the glue? Do you use a scraper similar to the one used for latex glues?
The outer framework is made from 2 1/2" wide timber that's cut into shortish lengths (about 24") and angled at the ends to form the frame. After gluing to the ply, this will then be cut to produce the shape of the curve. Should I cut a slot on the ends of the pieces and fit a tenon similar to using a "biscuit"? to strengthen the joins or not bother?
The frame will be fitted with 3/4" foam insulation. Did you use the pink higher density stuff or the white polystyrene stuff? How did you cut it? I was going to knock up a hot wire to cut it as a saw makes a terrible mess. Would the 3/4" thick stuff cut easily with a razor knife. I used to make foam wings for large RC aeroplanes and these were all cut with a hot wire.
What glue did you use to glue the foam in the panels of the frame?

Kody

[tony.latham]

I used PL Premium for the wood to wood and PL 400 for the wood to foam. Both adhesives were spread with a notched trowel. If I recall you have 45 minutes to work with the PL Premium. The 400 seemed shorter. Here's a couple of before and after pics with my weights holding everything down.

I'd use the same stuff again, but next time I'd only bother to buy the big tubes. A lot cheaper.

As far as joinery on the inside, I think it's a waste for strength since it's all going to be glued together with the skins. However, I biscuit joined my interior frames just to hold it together before I glued it to the plywood. - TL

[KCStudly]

I have used TB2 for all of my wood to wood, and GG for my wood to foam for blocking. I used 3M 30NF water based contact adhesive for some of my ply panels to foam and a rolled on a thin coat of TB2 for some others (my testing suggested that so long as there was not too much glue, the the large areas of wood were able to absorb the moisture and allow the glue to cure without exposure to air).

I do not intend to use the 30NF again; it was a lot more expensive and the TB2 worked fine if applied thinly and evenly.

I used biscuits for most of my wood to wood frame joints; they help greatly with alignment and positioning. At compound joints where I could not use a biscuit, and a few other spots I used either Kregg pocket screws or coated deck screws. I tried to use biscuits wherever possible and a minimum number of staples so that I did not have to worry so much about placing screws later in the build or running into the with cutting tools (still had problems with a few later, so am glad I did what I could to minimize).

The TB2 also says that it is not for structural use, but I feel that that is probably the lawyer speak to avoid liability.

When laminating large panels, regardless of glue type, it is key to distribute enough weight (or vacuum) and that it be spread as evenly as possible. The thin plywood is flexible and weight applied in one location will not necessarily translate to clamping force in adjacent areas.

I'm still waiting for someone to use a waterbed mattress as a panel press!