Construction adhesive for wood bows?

[mmattockx]

I have been doing experiments with different glues. The test consists of gluing two wood lams together (~20" long x 3/4" wide) and then bending them to the equivalent of full draw strain and holding them there for a couple days. One of the glues I tried was PL Premium construction adhesive. I didn't expect it to work because it cures to a hard but slightly rubbery consistency and I expected it to creep like mad under that continuous strain. Except it didn't...

The way I am checking for creep is to use a mitre saw to cut the ends of the glued up lams off, so there is a perfectly flat, square face on each end. Any creep shows up on the seam between the two lams. The PL test had a tiny amount of movement that left a very small lip that you could catch a fingernail on, but couldn't really feel running your finger tips over it. That didn't seem bad to me after the equivalent of 48 hours at full draw.

So, has anyone tried using any of the polyurethane construction adhesives to glue up a wood lam bow? I am thinking of only using the PL for gluing the lams together and then using conventional wood glue to glue on the riser blocks, nock overlays, etc.

Thoughts? Experiences? Opinions?


Thanks,
Mark

[Flem]

I think I would get creative on sourcing epoxy, rather than experimenting with inferior adhesives. Some of you Canadian bowyers surely could form a Co-op and purchase in bulk to bring the cost down. If there is somebody that lives in Vancouver, its a short drive to Port Roberts where you can avoid paying international shipping rates.
I'm sure there are other, more sketchy options for the more adventurous 

[KenH]

When I build wood-wood composite bows (no fiberglass, no sinew, no horn) like the Finno-Ugric Two-Wood bows, I use Old Brown Glue -- a liquid hide glue (https://www.oldbrownglue.com/) and/or Titebond II.  Have never had any problems with creep -- or any other issue for that matter. 

Titebond is available everywhere, and Old Brown Glue I order on-line.

[mmattockx]

When I build wood-wood composite bows (no fiberglass, no sinew, no horn) like the Finno-Ugric Two-Wood bows, I use Old Brown Glue -- a liquid hide glue (https://www.oldbrownglue.com/) and/or Titebond II.  Have never had any problems with creep -- or any other issue for that matter. 

Titebond is available everywhere, and Old Brown Glue I order on-line.

Titebond (II or III) is indeed OK, but I had issues with the lams cupping due to the moisture in the glue. I am going to try aluminum pressure strips to prevent that the next time around. Do you find it hard to keep the OBG from gelling/setting before you get the lams together and clamped?


Mark

[KenH]

I've always glued thin laminations under pressure of some sort, even though the lams I use are on the order of 1/4" thick and not particularly subject to cupping.

No -- the beauty of OBG is that it has a bit of an extended set-time, from uric acid, much like cutting Hide glue with Fish Bladder glue to extend the set.

[onetone]

Have used TB I, II, & III for years and have never had any issues w/ it bonding wood to wood. I prefer TB III cause it is waterproof and it is versatile - I even use it to glue fletches on both carbon and aluminum arrows! TB III also works well for gluing up risers without synthetics like G10 or fiberglass in the layup. With mixed materials like fiberglass w/ boo or wood lams in limbs I always use epoxy. G-2 from SystemThree is my pick. For tip overlays I prefer epoxy, but when pressed for time have used CA, both with good results. Construction adhesive has fillers in the mix, sometimes clay which would add undesirable weight, so I think that would nix it for limb glue-ups. So far have not used hide glue.

[kennym]

Have used TB I, II, & III for years and have never had any issues w/ it bonding wood to wood. I prefer TB III cause it is waterproof and it is versatile - I even use it to glue fletches on both carbon and aluminum arrows! TB III also works well for gluing up risers without synthetics like G10 or fiberglass in the layup. With mixed materials like fiberglass w/ boo or wood lams in limbs I always use epoxy. G-2 from SystemThree is my pick. For tip overlays I prefer epoxy, but when pressed for time have used CA, both with good results. Construction adhesive has fillers in the mix, sometimes clay which would add undesirable weight, so I think that would nix it for limb glue-ups. So far have not used hide glue.

So does your heat box do anything to the Titebond?

[onetone]

Kenny, I don’t use a heat box. Just let the epoxy cure at a warm room temp. for 48 hours. I decided the heat box was expedient, but not essential.

[kennym]

Ahhh,  I knew I had heard heat will cause  the titebond to fail . Thanks.

[Roy from Pa]

Titebond releases at 135 degrees.

[Pat B]

I was told 150 deg by Tite Bond's tech support when I wanted to remove a cracked hickory backing from a bow. With a heatgun and a screwdriver I got the hickory backing off...but I didn't check the actual temp.

[mmattockx]

Have used TB I, II, & III for years and have never had any issues w/ it bonding wood to wood.

I would much prefer to use TBIII if I can solve the cupping issues. I have never had issues with any wood glue as long as the joint is properly prepped and fitted.


Mark