Author Topic: Glue Seam Question.  (Read 6284 times)

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mekial2222

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Glue Seam Question.
« on: September 02, 2010, 02:58:34 am »
I'm not sure where to put this but I'm curious as to how important having a perfect glue seam is?  I tried my hand at gluing some red oak backed with maple, I don't have very many clamps (8) but I used some pieces of wood to help distribute the clamping pressure but I still got some glue seams as wide as 1/64" to 1/32"...  so what I would like to know is if I would try to separate it than re-glue or just go with it as is?  thanks.  BTW I used Tite Bond III.

Offline medicinewheel

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Re: Glue Seam Question.
« Reply #1 on: September 02, 2010, 03:27:09 am »
I wouldn't trust a glue line like that even if it was Epoxy!
Have you ever heard of the rope and wedges method, as used by the japanese bowyers?
Frank from Germany...

mekial2222

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Re: Glue Seam Question.
« Reply #2 on: September 02, 2010, 04:40:17 am »
I know of the method, the reason I didn't use it was because I don't have any wedges...  I guess I could make some out of my last couple failed attempts at a laminated bow...  any tips on ungluing Tite Bond III?  it says water proof so I don't know if soaking it will help or should I just saw it and hope for the best?

Offline Del the cat

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    • Derek Hutchison Native Wood Self Bows
Re: Glue Seam Question.
« Reply #3 on: September 02, 2010, 05:05:04 am »
A glue line should be almost invisible. Or as thick as a human hair, except I can't find any to compare with ::)
You need plenty of clamps of rubber strip ~1" wide cut from old inner tube used at full stretch to bind around, (It's a very tiring job and provides a good upper body workout!)
Any skimping on preperation glue mixing, clamping etc will only end in tears.
Del
Health warning, these posts may contain traces of nut.

Offline WillAdams

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Re: Glue Seam Question.
« Reply #4 on: September 02, 2010, 07:50:25 am »
While it's not optimal (or desirable, or pretty), I have managed to make a bow which started out having a glue seam almost that wide and even had some voids.

I filled the voids by squirting glue into them....

Most such problem areas were cut off when sawing out the bow, but the bow has two sections of seam which are ~1/64" thick.

You're not going to be able to easily unglue this and the backing strip will have warped to create the gap --- cut it off if the stave is worth saving.

IME gluing in Perry reflex requires fewer clamps and using a wide stave and wider backing strip are more forgiving (I'm considering cutting a bow-sized caul) --- unfortunately, even a dry run won't show how the backing strip will warp up at the edges if not held down there.

William

Offline 4est Trekker

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Re: Glue Seam Question.
« Reply #5 on: September 02, 2010, 09:52:26 am »
Yes, that's a very wide and dangerous gap regardless of the adhesive used.  However, in general, most epoxies have the ability to fill gaps and often require a surface that is roughed up a bit to get a good "bite."  The surface can be prepped with 60 grip paper, a hacksaw blade, etc.  On the other hand, the TiteBond glues requires a very smooth mating surface...NO voids and no rough spots to "get a bite."  They do not have gap-filling properties.

TiteBond releases at 150 degrees F.  You can use a heat gun to GENTLY heat the wood until it comes loose.  Best of luck.
"Walk softly, and carry a bent stick."

"And whatever you do, whether in word or deed, do it all in the name of the Lord Jesus Christ, giving thanks to God the Father through him."  Col. 3:17

Offline Eric Krewson

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Re: Glue Seam Question.
« Reply #6 on: September 02, 2010, 10:54:39 am »
Don't know about "dangerous" as far as a gap in concerned. I have done a bunch of glue-ups(over 30) and had every variety of gap from tiny gaps to voids I could actually put a puddle of Urac on top of and watch it flow back into the void. Fill your smaller voids with super glue don't worry about them.  For gaps that are filled with glue, no problem. Never had a failure from a wide gap or filled void.

I posted this before but here it is again. I started using my scrap bamboo for glue pads a while back when I glue up a BBO. The bamboo conforms perfectly with the backing and gives me a great glue line.

Here are some of my clamp pads



And one of my glue lines from yesterday.


Offline profsaffel

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Re: Glue Seam Question.
« Reply #7 on: September 02, 2010, 01:14:29 pm »
I wouldn't trust a glue line like that even if it was Epoxy!
Have you ever heard of the rope and wedges method, as used by the japanese bowyers?

Is there a specific place where this method is shown/discussed?
Professor of History, Student of Bowyery

mekial2222

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Re: Glue Seam Question.
« Reply #8 on: September 02, 2010, 02:00:23 pm »
so heating titebond III with a heat gun is my best bet?  I appreciate all the responses but I don't know how referencing epoxy relates.  there are no voids just thick glue lines, when I was gluing I placed alot of glue on the pieces but it appears I didn't have enough clamping force to squeze out the excess, the rubber band method sounds like a good one but TBIII needs air to dry doesn't it?  thanks.

Offline WillAdams

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Re: Glue Seam Question.
« Reply #9 on: September 02, 2010, 05:32:24 pm »
See Figure 29 in _The Flat Bow_ for clamping w/ cord and wedges:

http://www.archerylibrary.com/books/flatbow/docs/flatbow07.html

William

Offline bubby

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Re: Glue Seam Question.
« Reply #10 on: September 02, 2010, 06:11:42 pm »
Go out and buy a roll of stretch wrap, when ya do the glueup apply glue to both pieces of wood, put them in a vice at the handle and wrap from the handle to the tips, by making overlapping wraps and pulling as you wrap to apply pressure. When you see the glue squeeze out ahead of the wraps the wrap is plenty tight. If it's a flatbow thats all ya need to do, but I'd put a spring clamp on the tips. then I unwrap the next day, start working it the day after that. Hope that helps, Bub
failure is an option, everyone fails, it's how you handle it that matters.
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Offline Eric Krewson

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Re: Glue Seam Question.
« Reply #11 on: September 03, 2010, 01:14:09 am »
A couple of my friends use an inner tube wrap and get great glue lines.

Offline dusty

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Re: Glue Seam Question.
« Reply #12 on: September 03, 2010, 08:03:17 pm »
The quad lam English longbow I posted a few weeks back was glued up using rubber strips cut from old inner tubes
I don't use any other method Cheap and works really well