Main Discussion Area > Bows
Heat treating boo backed bow
Kidder:
I’m starting on what will eventually be a boo backed hickory bow and am looking for input on heat treating the belly. I’ve searched online and have yet to see where anyone has done a heat treated boo backed bow of any kind, but I can’t imagine this would be a first. I use EA 40 for the glue up. Questions related to timing of the heat treat and issues it presents.
1) I could wait until it’s glued up and tillered. What is the likelihood of damaging the epoxy if done this way?
2) I could heat treat the belly on a form like one would do for a non-laminated bow and then glue it up after. For the heat treat to be effective I imagine I’d have to be tillered very well on both belly and back pre glue up and the belly would have to be very light otherwise it’d be an 80 lb bow or I’d scrape away all the tempered wood. If done this way should I put in any Perry reflex or just the heated in reflex? If so how much would be appropriate given that the belly will be tempered and at risk of a tension break?
Any other thoughts would be greatly appreciated.
superdav95:
I would go with option 2 imho. Hickory will be great in compression if thoroughly heat treated thru with out scorching the belly. You can have a form prepared to toast your hickory first to the reflex you want. If you have made a boo backed hickory before of this style you can use those thicknesses as a reference for this build so that you don’t have to scrape away too much belly wood. The only glue I’m aware of that might possibly allow any heat treat after glue up is urac 185 or replacement unibond 800. Even better would be system three g2 epoxy. West systems too. The g2 is rated up to 170 degrees if your doing a mild heat treatment if insistent on heat treating after glue up. I think you’d be better to do a solid heat treatment of hickory lam separately and then laminate with 2:1 ratio with smooth on ea 40. It gives better performance at that ratio if then placed into hot box to fully cure. I’ve done ambient temps for overnight cure on ea40 at that ratio with good results on wood to wood glue up. My boo to wood glue ups also were fine at non hotbox glue ups. I guess time will tell for the difference. Hope this help in your decision. Reach out if any more information needed. I know Allen case on here is a glue expert too so he could chime in on this for ya. I’ve heard that it’s been done after glue up with certain glues but it seems to me that to get the most benefits of proper heat treatment of hickory you’ll need to go well above the 170 mark in my opinion. 250-300 more like it. FYI.
Del the cat:
If you want to go with option 1, this post from my blog may help. (The heat treating bit is down the bottom of the post)
https://bowyersdiary.blogspot.com/2015/02/two-steps-forward-one-step-back.html
Del
Eric Krewson:
I have heat treated several bamboo backed bows that turned out sluggish because I used softer osage in them. The heat treat turned them into fine bows. I used Urac glue in one and Unibond in the other that I can remember, these glues can stand a lot of heat so I had no problems.
Gordon:
Heat treating limbs that have already been glued up is asking for trouble. Best avoid potential delamination and heat treat the belly before you do the glue up.
Navigation
[0] Message Index
[#] Next page
Go to full version