bow backing glue????

[dave_t_aber]

I have go hold of some of the glue, under the name extramite.
I will use it tonight.
cheers,
will let you know how it goes.
If this bow goes right ive got more bows in mind which i plan to make over the winter.

[iori jones]

Hello Dave,
I"d like to raise a few points on this subject. I have over 50 yrs. experience in woodworking, I"ve done a lot of laminating and used a lot of Cascamite, but none of what I"ve laminated has been subject to very strong bending forces, and frankly I"m not at all sure that cascamite is the right glue for the job! It is fantastic stuff, but when it"s fully cured, (about 3 weeks!) it is incredibly tough and hard. I once took a piece about 2ins. dia. & 20 mm. thick, laid it on a concrete floor, and hit it with a hammer, nothing happened!
Amazing, but can it take the repeated and powerful bending forces of a bow?It may very well be able to, but I think you would be well advised to get professional advice from somewhere. I note that on the Flybow site they sell Titebond and an epoxy glue, no Cascamite, that surely says something! Give them a ring.
You do not mention whether it is a reflex you are making, if it is, you can forget rubber bands, if you are you"ll need two shaped cauls and a lot of G-cramps, or one caul and a strap. If you are going that way let me know and I"ll send you the necessary words and pictures. One other thing, have a few practice runs, otherwise it is almost axiomatic that you"ll run out of either time or cramps! One workshop I worked in, everyone used to gather round to watch, and take bets on the outcome!
I wish you the very best of luck in your effort, think how proud you"ll be when you"ve succeeded.
Iori Jones

[dave_t_aber]

Iori,
Thankyou for your advice. I have unfortunately glued the backing this afternoon. The bow in question is a ordinary longbow, i have not reflexed the bow. I am confident that I have applied even pressure along the backing, by winding rubber strips around the bow all along the length. Both the backing and stave were planed dead flat, but roughened, which i guess would mean there is only a minimal layer of glue between the two, which should help.

I agree though, there is a large amount of torsion applied on the backing when in use, and i suppose the same torsional forces would act to slightly stretch the glue line, and possibly part the backing from the stave if the glue didnt flex with the backing.

I will wait and see what happens when i work on the bow, in about 3 weeks. If it breaks, it breaks, it will be a lesson learned, im not expecting total success, or at least not a perfect bow. This will be my 3rd longbow, after two previous failures.

thanks for sharing your experience with me Iori, I will see how it goes. I will also run a test ( a little late) with bamboo on a similar strip of hardwood with cascamite, and test it before i work my stave, that way if it fails, i can take the backing off, and still have a perfect unworked stave for a second attempt.

thanks
david

[RichardH]

I don't have my copy to hand right now, but I seem to recall Pip Bickerstaffe's book mentioning Cascamite. I have also spoken to a local bowyer who uses Cascamite in his (reflexed) bows.

A quick google brought this from this very forum - if I may quote:

Originally Posted by Yew Selfbow

Over the past week, I've been building my first long bow under the watchfull expert eye of Pip Bickerstaffe and his collegues at his Kegworth workshop and now it's finished. The bow is for indoor shooting,(50lb@28 1/2") and is a laminate of an Osage belly, Bloodwood, Maple and Bamboo core with a Bamboo backing. The arrow plate is milky white Indian Samba deer horn and the almost transparent nocks are from an English dairy Longhorn Cow.
... and does it shoot....you bet it does.....

...and later on in the thread..

Originally Posted by Yew Selfbow

Because of the oily nature of the Osage and Bloodwood we decided on a two stage lamination glue up. The first stage was to glue up the woods that had open cell structures (bamboo and Maple) for those we used Cascamite. For the Osage and the Blood wood we used resin based Resorcinol, we had to ensure that the Maple "buffer" laminatiom was between the Bloodwood and the bamboo. So on one side of the Maple it was glued to the bloodwood with Resorcinol and on the other face it was glued to the bamboo with Cascamite.

So it sounds like Cascamite is not an unusual glue to use.

[dave_t_aber]

Thankyou richard,
that gives me a little more confidence. I have to say, it seems like sound advice im getting all round on this thread. I will still test the strength of the test piece i glued up with cascamite, prior to working the bow, and if thats fine, then i will, after the 3 week cure period begin to work the bow. Its a test of my patience, waiting the 3 weeks for the glue to cure, but i know its worth it.

thanks again
dave

[ThePinkOne]

Cascamite is much used, but recently a few bowyers around our neck of the woods have reported failures with the glue- there is a view forming that when the name changed from cascamite to to "extramite" (I think) the formulation changed slightly too. One to watch.

Personally I like hot hide glue- particularly since I got my electrically-heated thermostated gluepot!

P.

[dave_t_aber]

my bow is coming on now, its in the later stages of tillering, ive taken it to half draw, but not full draw. Ive not heard any creaks or groans from the wood, and the glue seems to be doing fine. Im taking my time with it, and keeping the limbs on the wide side, so as to spread the forces out slightly. I hope for it to end up, at just under 50lb draw weight, i dont want to force a higher draw weight out of it, as its only my 3rd bow, and fingers crossed its looking better than the previous two!
cheers for advice
dave