glue and heat?

[Jim Davis]

Now, I'm not very interested in speculation here, but am interested in your experience.

I have sometimes found that a backed bow ends up with the limbs not curved the same--either reflex or deflex. I have thought of heating the belly to correct the difference, but expected I might end up delaminating the limb. To keep it specific, I am using Titebond II. I'm interested in the results with other glues too, but Titebond II is what I have been using.

Any success or disasters to report?

Jim

[PatM]

There has been quite a few references to people experimenting with heating various glues and getting away with it, or not.

[Pat B]

I needed to remove a rotten hickory backing from a bow that was glued down with TBIII glue. I called the TB tech support and the guy I talked to told me that all TB wood glues release at 150 deg(F). That was the ticket to removing the bad backing so I could add a good one.
 I think with Urac(Unibond?) you can heat enough to make corrections without adversely affecting the glue but I've never tried it.

[k-hat]

I had a hickry backed oak bow that shifted on me during tiller and required correction.  I gently heated and did the correction, being careful to keep the heated area clamped tight the entire time.  If I remember correctly, I wrapped the limb in foil and warmed from both sides to keep the glue joint as cool as possible. Turned out fine, well shot in with no seeming ill effects.  Sent off and still fine to my knowledge.

Forgot to add it was glued w TB II or III

[DC]

CA releases at 190F. I've got the tips in my steam bag to prove it

[Dances with squirrels]

I use Smooth On most times and have heated backed bows many times to make alignment corrections without I'll effect. On a few of those bows I had to do it several times to get it just so.... still no issues.

I paid no particular attention to whether or not the original glue ups were heated during their cures. I often cure them with heat, but not always.

[Springbuck]

It kinda sorta works sometimes.  We get warned against quick surface heat treating because it generally does little, but what if you need just a little?  The thickness of the belly come into play, but, yeah say you got a tiny spot trying to flatten too much near a bamboo node on the back or whatever.  By all means cook it a little.  But, don't over-do.

Also, a lot of backed bows I make had tropicals like jatoba, massaranduba, and ipe, which couldn't give a two nickles about heat treating anyway.  But, when I had over 1/4" thick black locust on the belly it worked ok.

I never had one delaminate completely doing this, but I did have one where the thin edges of a trapped hickory back curled and gapped a little at the glue lines, which was unsightly.

[DC]

Something in the back of my head says that we could get away with a lot weaker glue for things like lams and backing but who is going to risk a perfectly good bow by trying school paste to hold the boo on? Well Tim Baker might but not me. That said I think degrading excellent epoxy or TB3 a little by heating a little probably won't destroy the joint but who's going to say what a little is? I wouldn't heat a glued bow unless the only choice was either heat it or burn it.

[mullet]

Last year Pappy and I brought an osage stave bow back into tip alignment using heat. I had snake skins on the bow and was worried about messing them up and still getting it hot enough to make the corrections to bring the tips back in so the string would quit jumping off on the release.With both of us twisting and lightly heating it shoots real good now and didn't harm the skins or glue. I had used TB3.

[Jim Davis]

Thanks for all the input guys. I think I will have to glue up a test piece before I decide whether to heat that finished bow. The top limb has taken about 1/2" of set and the other limb is nice and straight unbraced. Just doesn't look good since I'm giving the bow away. But I don't want to ruin it either.

Jim