Plywood, LVL, LSL, or 2x8?

[bowhunter15]

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?

[Bowjunkie]

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.

[Mark R]

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.

[PV]

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

[nashoba]

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.

[Robertfishes]

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.

[bowhunter15]

Looks like plywood it is!

[bamboo]

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

[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.

[bamboo]

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

[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!

[bowhunter15]

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

[kennym]

Originally 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

[fujimo]

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!    

[Jerry Gille]

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

[Mad Max]

Originally 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

[bowhunter15]

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.

[bowhunter15]

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