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Main Boards => The Bowyer's Bench => Topic started by: Keith Wolfe on March 06, 2019, 09:33:10 AM

Title: Toasting belly question
Post by: Keith Wolfe on March 06, 2019, 09:33:10 AM
I glued up a hickory backing strip on a hickory pecan bow with tb3. Was wondering if toasting the belly once tillered would weaken the glue since tb is heat sensitive. Belly is a little over a quarter to 3/8" thick. thanks!!!!!
Title: Re: Toasting belly question
Post by: Pat B on March 06, 2019, 09:57:09 AM
All Tite Bond glue will release at 150 degrees. You might be able to do a light toasting but I doubt it will help. Did you add reflex at glue-up?
Title: Re: Toasting belly question
Post by: BMorv on March 06, 2019, 11:09:22 AM
X2 on Pat.  150 degrees isn't all that much.  That's not even close to heat treat temperatures. 
TB3 is the least heat tolerant of the common bow building glues.  A few seconds with the heat gun and it will start to melt/release. 

That has it's positives and negatives.  It's nice when you can use a heat gun to remove a damaged backing...

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Title: Re: Toasting belly question
Post by: Pat B on March 06, 2019, 11:22:39 AM
I found out about the heat release when I called TB tech support to find out how to remove a rotten hickory backing and the tech guy told me about the 150 deg. Like BMorv, it worked like a champ.
Title: Re: Toasting belly question
Post by: Roy from Pa on March 06, 2019, 11:28:54 AM
There have been times when I wished unibond800 was that easy:)
Title: Re: Toasting belly question
Post by: Pat B on March 06, 2019, 03:17:56 PM
He could probably toast the belly had he used Unibond. ;)
Title: Re: Toasting belly question
Post by: Wolftrail on March 06, 2019, 03:33:36 PM
X2 on Pat.  150 degrees isn't all that much.  That's not even close to heat treat temperatures. 
TB3 is the least heat tolerant of the common bow building glues.  A few seconds with the heat gun and it will start to melt/release. 

That has it's positives and negatives.  It's nice when you can use a heat gun to remove a damaged backing...

I have never heat treated a bow made with TB3.. But, but and I will repeat I have heated the last 6-10" of the tips to straighten out the limb and never had any problems, I applied enough heat to gently twist the limb so I was not going wimpy using the heat...
Title: Re: Toasting belly question
Post by: Keith Wolfe on March 06, 2019, 09:23:35 PM
I figured it was going to be a bad idea. I think ill thin the backing from 3/16 to an eighth, leave the belly relatively rectangular with rounded edges, and trap the corners on the back. I'm just still gun shy from a belly failure i probably crowned too much while not trapping back or backing with anything so i was entertaining the idea of strengthening the belly a little. How much do y'all come in when you trap the back? Like an eighth from the corner or so???? Thank you. Just being paranoid.
Title: Re: Toasting belly question
Post by: Wolftrail on March 07, 2019, 04:43:16 PM
I figured it was going to be a bad idea. I think ill thin the backing from 3/16 to an eighth, leave the belly relatively rectangular with rounded edges, and trap the corners on the back. I'm just still gun shy from a belly failure i probably crowned too much while not trapping back or backing with anything so i was entertaining the idea of strengthening the belly a little. How much do y'all come in when you trap the back? Like an eighth from the corner or so???? Thank you. Just being paranoid.

"How much do y'all come in when you trap the back?"  I have gone at least 3/16"  maybe 1/4".
Title: Re: Toasting belly question
Post by: Pat B on March 07, 2019, 04:56:58 PM
I think it would depend on the situation. Wood is stronger in tension than it is in compression and different woods have different values for both tension and compression. I think basically 1/32" to 1/8" from each side depending on the wood used or the wood(boo) combo used.