Glue strength test
#6
  
https://www.youtube.com/watch?v=_vIszsybR4M
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in Navy Times, November 1994]


Jack Edgar, Sgt. USMC Korean War 51/52
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#7
  Re: Glue strength test by Timberwolf (https://www.youtube....)
She sure had a ball doing those test.
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#8
  Re: Glue strength test by Timberwolf (https://www.youtube....)
Thanks, Jack, interesting video.

She did figure out that plywood is not the best test bed for glue joints, at least....  She also admitted her bottle of Titebond III was "old", so I don't know if it was a fair test.  In the test linked to below, the waterproof PVA outperformed even epoxy...

http://www.oldbrownglue.com/images/artic...ue_FWW.pdf

I just used some based on that test to repair a guitar neck tenon, we will have to see if it holds up.

I recently bought my first bottle of Old Brown Glue from TFWW, and I am very impressed with it.  It's not liquid in the bottle, it still takes a warm bath to liquify it so isn't just a grab and go glue, but once heated up you have more working time than with standard hot hide glue.
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#9
  Re: RE: Glue strength test by Nordic (Thanks, Jack, intere...)
(04-10-2019, 09:58 AM)Nordic Wrote: <SNIP>
I just used some based on that test to repair a guitar neck tenon, we will have to see if it holds up.

I recently bought my first bottle of Old Brown Glue from TFWW, and I am very impressed with it.  It's not liquid in the bottle, it still takes a warm bath to liquify it so isn't just a grab and go glue, but once heated up you have more working time than with standard hot hide glue.

Having a son's cello repaired and a brother's violin repaired, it is my understanding that easily releasing glue bonds is as important, if not more, as making a joint bond well. The last 'doctor' showed me a kitchen table knife as the means and gauge for separations. And, if it is to fail (suffer accident) it should fail cleanly at a joint. In both instances the breaks or failures were at joints. This criteria makes hide glues the preeminent choice in manufacture and repair of wood instruments.

I keep thinking my own wood gluing needs to follow suite. Salvage and repurpose is my second name, and the old furniture, using hide glue, is a dream to deconstruct.
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#10
  Re: Glue strength test by Timberwolf (https://www.youtube....)
(04-10-2019, 12:01 PM)hbmcc Wrote: Having a son's cello repaired and a brother's violin repaired, it is my understanding that easily releasing glue bonds is as important, if not more, as making a joint bond well. The last 'doctor' showed me a kitchen table knife as the means and gauge for separations. And, if it is to fail (suffer accident) it should fail cleanly at a joint. In both instances the breaks or failures were at joints. This criteria makes hide glues the preeminent choice in manufacture and repair of wood instruments.

I keep thinking my own wood gluing needs to follow suite. Salvage and repurpose is my second name, and the old furniture, using hide glue, is a dream to deconstruct.

I agree.

On the guitar I am repairing using the PVA glue, it was the tenon itself that broke - it did so because the original dovetail had been glued together with epoxy at the factory and did not release with extensive amounts of steaming  and it needed to come off...  It only did so by partially sawing it off and breaking it.




I needed a permanent glue to re-glue that all back together, not one that could be released later.  I removed the top also, and that is what I'm using the hide glue for, as well as for the glue I will use when this neck goes back into the guitar.

This particular guitar was never meant to be repairable, it's an early 80's Takamine I've owned since it was new... They used epoxy everywhere.  They used a plywood for the wood this neck glued into, that plywood separated long before the dovetail joint gave up. I ended up partially sawing through it, and broke it - so I ended up having to remove the top in order to repair.




This is what happens when you don't use a releasable glue...
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