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Main Boards => The Bowyer's Bench => Topic started by: Zradix on May 25, 2013, 02:38:00 PM

Title: uni bond 800..how hot till it lets go?
Post by: Zradix on May 25, 2013, 02:38:00 PM
Hi Guys.

I've heard that tb3 needs about 150˚ to let go.

Does anyone know what type of heat is needed for unibond 800?
maybe it doesn't let go with heat at all..I really don't know.

I'd like to try to save a riser block of a junk bow.
I know I can cut/sand it off but heat could be easier..
..drink a beer while the heat gun does the work kinda thing..lol
Title: Re: uni bond 800..how hot till it lets go?
Post by: Pat B on May 25, 2013, 03:19:00 PM
Contact the manufacturer. Thats how I found out about TB glue releasing at 150deg.
Title: Re: uni bond 800..how hot till it lets go?
Post by: Roy from Pa on May 25, 2013, 03:48:00 PM
Band saw it close then sand the rest. Then drink the beer:)
Title: Re: uni bond 800..how hot till it lets go?
Post by: Zradix on May 25, 2013, 03:54:00 PM
really gotta get one of those...lol
Title: Re: uni bond 800..how hot till it lets go?
Post by: Echatham on May 25, 2013, 04:01:00 PM
whats that... a beer or a bandsaw?
Title: Re: uni bond 800..how hot till it lets go?
Post by: Zradix on May 25, 2013, 04:07:00 PM
band saw of course...I did say just one...lol
Title: Re: uni bond 800..how hot till it lets go?
Post by: vanillabear? on May 26, 2013, 12:07:00 AM
Title: Re: uni bond 800..how hot till it lets go?
Post by: D on May 26, 2013, 12:17:00 AM
I agree on the cut first drink beer after.  I seen pics yesterday of a guy I know that got his thumb caught in a jointer.  He now has no thumb...I don't think beer was involved but still no good at all  be careful everybody.  As far as know it does not let go (like everyone else said) lol.
Title: Re: uni bond 800..how hot till it lets go?
Post by: Roy from Pa on May 26, 2013, 08:24:00 AM
Buddy of mine lost the end off his index finger on a jointer, they scare the crap out of me.
Title: Re: uni bond 800..how hot till it lets go?
Post by: tenbrook on May 26, 2013, 12:08:00 PM
Just a heads up that TBIII does NOT release at 150 degrees but actually gets stronger when cooked at that temp.

Now TBII WILL release at 150 degrees.

This is the information I received from the manufacturer and I have found the same results with my own experimentation.

Hope this helps clear up some confusion.

Tenbrook
Title: Re: uni bond 800..how hot till it lets go?
Post by: Pat B on May 26, 2013, 12:59:00 PM
Tenbrook, I called the TB folks and asked them specifically about TBIII and they told me that all TG carpenter glues released at 150deg(F). I wanted to remove a bad hickory backing. Thats why I called.
Title: Re: uni bond 800..how hot till it lets go?
Post by: wood carver 2 on May 26, 2013, 01:01:00 PM
QuoteOriginally posted by Roy from Pa:
Buddy of mine lost the end off his index finger on a jointer, they scare the crap out of me.
X2 for me. Beer comes after I'm done with the power tools. A guy I worked with once was wearing a loose fitting sweat shirt which went into the 12 inch jointer. He was lucky to only have the shirt ripped apart.
Dave.
Title: Re: uni bond 800..how hot till it lets go?
Post by: Zradix on May 28, 2013, 12:07:00 PM
Here is the answer received from the manufacturer...

John,

Unibond 800 does not have a release temperature because it is whats called a thermosetting glue where as Titebond is a thermoplastic glue which will soften at higher temperatures. Because thermoplastic glues, (especially the type Unibond 800 is) create a chemical reaction by mixing two parts together they stay rigid at higher temps.

This is probably not what you want to here but its part of what makes the bond and the longevity of the bond be so good.
Title: Re: uni bond 800..how hot till it lets go?
Post by: tenbrook on May 28, 2013, 06:20:00 PM
QuoteOriginally posted by Pat B:
Tenbrook, I called the TB folks and asked them specifically about TBIII and they told me that all TG carpenter glues released at 150deg(F). I wanted to remove a bad hickory backing. Thats why I called.
Pat I too have called and was told that the tbIII gets stronger when heated.  I have found this to be true with my glueups as well.  I'm gonna call again and get the particulars...stay tuned!    :D
Title: Re: uni bond 800..how hot till it lets go?
Post by: tenbrook on May 29, 2013, 04:35:00 PM
Okay just got off the phone with titebond....Sounds like we are BOTH right.   :)  

TitebondIII deos soften at 150 degrees.  

However when heated above 150 (160-180 degrees) then allowed to cool it activates a secondary cross-linking in the glue making it SUPER strong!  After it has been heated to temps between 160-180 then allowed to cool it becomes so strong and impervious to heat it will not come apart when soaked in boiling water (they actually test for this).

Hope this helps!   :thumbsup:  

Tenbrook
Title: Re: uni bond 800..how hot till it lets go?
Post by: Zradix on May 29, 2013, 04:36:00 PM
cool info!
Title: Re: uni bond 800..how hot till it lets go?
Post by: eflanders on May 29, 2013, 11:54:00 PM
I am in the process of building a small boat using cedar strips glued together with TBIII. (It is commonly used by wood canoe builders.)  Anyhow, there are several spots where I have to bend the strips to fit the form using heat from a commercial duty hot air gun.  Before I tried doing this I consulted with many others as I was concerned about the glue letting go and I was assured by everyone that tenbrook is correct.  So far this has been my experience too.  The glue does  soften and will move with the joint and it will not release it's bond IF the joint is still held together as it is bent and allowed to cool to room temperature.  Now if one wanted to purposely take apart something that was glued together with TBIII, heating it until it softens (150' or so) is the only way I know of to do this.

So if a bow you built with TBIII is left in an enclosed vehicle on a hot sunny day going to delaminate on you?  Maybe yes and maybe no... Don't tempt fate by doing it!

By the way, almost all glues can be made to release by using heat.  But you have to try or force them to release the bond by prying apart the pieces bonded together by the glue.