HHG failures

[inoz]

Hi all,

I used HHG to attach the bridge on my latest and had it rip off twice when tensioned up. I thought I made it properly.
1:1.9 by weight glue to water, let it dissolve for @ 3 hours, double boiler style heat not going over 140 degrees.
The guitar surface was finished and I put acetone on it and then scraped the finish off. I've never used acetone to do this before, I was just trying to be quick, was this my undoing?
Now it's a pitted mess and I'm thinking I'll have to epoxy it on.
Thoughts?

[kiwigeo]

What's the finish?

I normally just scrape away finish with a scalpel before gluing on the bridge.

Your glue mix ratio isn't much different from what I use.....I eyeball equal quantities of glue and water and let it soak for a few hours before heating it up.

If youve still got some of the glue...glue a couple of pieces of wood together and when set check strength of the joint.

[inoz]

Hi Martin, It was NC lacquer.

[auscab]

How were you clamping the bridge on , and how many seconds did you take to do it ?

I was doing practice runs with mine and making sure I had it clamped within 30 to 40 seconds in a warm room on the final run.
Much longer or not enough pressure and the glue can gel leaving a gappy join ,and gappy HHG joins fail.

[Tod Gilding]

was this old stock HHG that you have used before without incident ?

[inoz]

I used 3 bridge clamps and no I don't think it was long enough to gel.
The glue was old and I've used it before without incident which makes me suspect the acetone as it's the only thing different.
Could it have contaminated the gluing surface? I'll do as martin suggested as I have some left over and test a join of scrap.

[Kim]

It is unlikely it was the acetone on its own unless it was coated over with glue so quickly that it never had the chance to gas off. However I think it is quite likely that the acetone thinned the finnish and took it 'into' the wood to seal it from the HHG making purchase. If most all of the glue stayed on the bridge then this is probably what happened. If the glue is still attached to each surface then I suspect you were just too slow in getting them together.

BTW HHG be it in pearl or granule form does not have a shelf life. Even when mixed it will last for a very long time if stored in the fridge.

viewtopic.php?f=1&t=2557&hilit=old+hide+glue

In fact the only line I would draw on storage for mixed glue would be if I smelt 'rotten' instead of how HHG normally smells, or if it were to liquefy when still in the fridge. To determine whether or not it was the acetone/nitro wash that caused the problem, or just being a bit too slow that had caused the issue, I would recommend the "pine in a vice test" as per the above link.

Cheers

Kim

[Allen]

Acetone will pull other things from surrounding finishes, resins out of woods etc. and contaminate a surface. I never, ever use it after learning the hard way on a few joints. Perhaps like you have. Fresh scraping and blowing clean is all that is required.

If you've used that particular glue prior to this in that ratio with no problem, then using the acetone is the likely culprit.

If you want to make sure that your HHG joint is going to be as strong as possible, then size the surfaces prior to glueing. That means to put a thin watered down coat on both surfaces and let dry. Depending on air flow and humidity anywhere from a couple of minutes to no more than 1/2 hour.

Now you are dead certain that you have glue penetration on both surfaces. The rest is easy. A quick coat of hot glue again on both faces and clamp together.

[inoz]

Thanks everyone, I did a test joint and the HHG from the same batch stuck like shit to a blanket.
So Allen & Kim get the chocolates it must have been the acetone. Another lesson learned.

[inoz]

On a side note, what do you think of 192 strength, is id adequate for all our applications?

[Kim]

On a side note, what do you think of 192 strength, is id adequate for all our applications?

Perfect! Moving up the grain strength ladder incrementally closes the open window for no benefit, because you'll never need anything stronger, than 'plenty' strong enough.

Cheers

Kim

[foxfair]

I am reading through old thread of HHG, and the one Allen mentioned before : http://toolsforworkingwood.com/store/item/MS-HIDEGL.XX
doesn't ship out of US anymore.

Does anyone have a local suggestion, like ALS or something?

[Allen]

If you tell Joel that you accept responsibility for the glue being confiscated by customs, then they will ship to you. At least they shipped to me. It's a hit or miss affair if it gets through. So I always order 5 lbs and take my chances.

Other wise you can get a 1lb tin from Stew Mac. Never heard of anyone getting it confiscated from them.

[Tod Gilding]

What is the problem with toolsforwoodworking.com HHG ?

Does Australian Customs & border protection have a couple of Luthiers working for them ?

I just looked through Prohibited & restricted imports and couldnt find any where that HHG was not allowed.

Also couldnt find the old thread that Howard mentioned, More Info Please Al

[kiwigeo]

What is the problem with toolsforwoodworking.com HHG ?

Does Australian Customs & border protection have a couple of Luthiers working for them ?

I just looked through Prohibited & restricted imports and couldnt find any where that HHG was not allowed.

Also couldnt find the old thread that Howard mentioned, More Info Please Al

Hide glue is an animal derived product and is subject to restrictions. All outlined here:

http://www.aqis.gov.au/icon32/asp/ex_ca ... essionID=0

[Tod Gilding]

Thanks Marty I was looking here http://www.customs.gov.au/site/page4369.asp No mention of animal derived products.

It's funny that I have had them open my package of HHG before and just left a pamplet to say they had been there and let it go

[auscab]

Davis joiners pearl glue from NZ , 135 Connal street Christchurch NZ comes in 25 kg bags. I don't know if it comes any smaller over here.
The same colour as you see squeezing out of the joins of all those nice old guitars with all that tone because of its age BS.
Holding together furniture that goes through all sorts of humidity related neglect and stresses many times worse than a cared for instrument.
possibly cheaper as well ?

[WaddyT]

Something like over 50% of glue failures are due to a poor joint fit. If the Acetone didn't seal the top, then, is it possible that you had/have gaps in the fit between the bridge and top?

[simonm]

I found Michael Thames you tube videos very helpful for bridges and HHG. You should get straight to them if you put "michael thames bridge" into you tube.

[matthew]

just got 2 lbs from LMI. And a few otherbitsnpieces.

Ordered Monday it was here by end of the week.

customs dint touch it.