For building a glue-up form,  like the two-piece forms used for the air hose method,  I often see two pieces of 3/4" plywood laminated together. It's expensive comapered to the other options,  Laminated Veneer Lumber,  Laminated Strand Lumber (both engineered composite woods,  high strength and straightness) or a regular old 2x8 or 10 or 12.

Does anyone have experience with the composite lumber options? And would a pine board be sufficient if it was jointed and planed?

I've used plywood glued and screwed together and LVL. Both work great.

The only material I had a problem with was particle board. It broke apart in the oven.

I myself would not skimp on the form. A well designed and made form will make good bows, A bad form will be a total waste.I am in the process of retooling a form, its more work than making the bow from it, but its critical to make it right with the right material.

All of the forms I've made with LV's have warped,most sooner rather than later even though I use 1 1/2" angle iron on the sides as a stiffener.. I've since gone to MDO (signboard)plywood (2) 3/4" and spacer with the angle iron and have had no issues

I'll second what PV said . The one and only time I used LVL I had a lot of problems with that form and have since tossed it out and remade it out of Baltic Birch that I glued and screwed together.

I have only used Cabinet grade Birch plywood myself. There is a Cabinet shop down the road from my house,I usually buy 3/4" from them..But I bought a sheet of 1/2" from Lowes once too. I glue the sheets together on a perfectly flat surface with tite bond II glue and use a bunch of 1 1/4" wood screws. my oldest form was built June of 2009 and its still straight.

Looks like plywood it is!

look into laminated scaffolding planks-

-one more thing-tite bond can be an issue at the temperatures we cure at


http://www.kennisonforest.com/products/sure-lam-lvl/

very stiff and uniform

The titebond II shouldnt work at the 160 degree temps. I put a lot of 1 1/4" wood screws into the form, I think thats what really holds the form together. Mr Bingham used wood glue and screws in his how to build a bow videos so thats what I used to build my first form in 2009..and all the other forms since then, I think the screws are the key to keeping everything in place.

without doubt Robert!!--my oldest form is tite bond and many many screws!!

 I've been using  urethane glue [gorilla] on forms it doesn't seem to move

i concur- i use 1/2" ply  and lots of screws- and i run the screws from both sides- on about 4" squares on one side- and then 4" squares on the other side- placed alternately- so thats about a screw every 2" or so- never had an issue!

I've been using Unibond 800 which cures at pretty reasonable temperatures, but screws seem like a pretty good step to ensure longevity.

QuoteOriginally posted by fujimo:
i concur- i use 1/2" ply  and lots of screws- and i run the screws from both sides- on about 4" squares on one side- and then 4" squares on the other side- placed alternately- so thats about a screw every 2" or so- never had an issue!

Yep, and mark out your bow profile on both sides before you "screw it up" . Then you don't have screw paths in form face after you rout it.

Don't ask how I found out! LOL

absolutely spot on kenny- i ran the screws in for my first form. smartened up a bit after that- not much, but just a bit!    

I might have a screw "worm hole" on one of my forms too...

QuoteOriginally posted by Robertfishes:
The titebond II shouldnt work at the 160 degree temps. I put a lot of 1 1/4" wood screws into the form, I think thats what really holds the form together. Mr Bingham used wood glue and screws in his how to build a bow videos so thats what I used to build my first form in 2009..and all the other forms since then, I think the screws are the key to keeping everything in place.

X 2

I took a trip to Menards and picked out a nice,  straight 3/4"x2'x8' ACX plywood. They couldn't cut there, so I'll have to use a table saw to turn into two 1'x5's and laminate, joint, route profile, and screw together.

Heres the form all routed to the template. Now I just need to reinforce with screws.