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I've been wanting to learn to use HHG for a while now and have played with it a little, sometimes it seems ok and sometimes not. There was a discussion a few days back on fish glue and naturally HHG came up in that as they are realted. I believe Paul Woolson might of mentioned he had similar experiences to mine, Paul correct me if I'm wrong.
Any way to make a long story longer, I mananged to hook up with a well established Cello maker somewhat near me and she went over her HHG proceedure. She measures nothing and really encouraged me to try HHG again, so using her approach I tried again.
So.. here's what I did.
I used an Maccasser Ebony bridge blank (from the Zoot man himself) and a scrap from an old top, looked like sitka.
Prepped the ebonywith a scraper and the sitka was sanded to 220.
I did monitor the temp of my rival hot pot but did not measure the amount of water I used. I just added water until it was just a little over the top of the glue.


My shop was not quite as warm as the photo indicates there was a portable light shining on the thermometer. It was actually about 77 F. and as you can see the HHG was about 140ish.
The mixed glue looked like this and I used an oral syringe to dispense the glue with.


Next I thinned out some HHG with water and wiped it on both surfaces, the way my cello maker friend does it.
These sat around for approximately 10 minutes before actually being glued up while I was getting my vacuum set up ready.
IMG]useruploads/JimW/2006-08-19_133908_hgt3.jpg[/IMG]

I then took my HHG syringe from the hot pot and applied a generous amount of glue to the bridge blank. I made no special effort to work extra fast nor did I heat the bridge blank. Then I placed the assembly in my vaccum frame, I use vacuum to clamp my bridges on so it was representative to me.


I left the assembly under pressure for 30 minutes and removed it form the vacuum press and set it aside.
I then ripped it apart 12 hours later and this is what I got.



I'll repeat this test a few times to make sure I actually have a process.
Hopefully out of this long winded thing it'll encourage others who are interested it HHG but aren't so sure. It's encouraged me to keep exploring it.

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Jim Watts
http://jameswattsguitars.com

Ok... just so I have this straight. You put some on both parts and let it cool, then applied it again before you clampped it up?

That is interesting.

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Brock Poling
Columbus, Ohio
http://www.polingguitars.com

That's what I did.
I thined out some glue as a sizing and wiped it on both pieces.
Then applied a "standard mix of glue.

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Jim Watts
http://jameswattsguitars.com

Hesh, I didn't measure anything mixing the glue.
The cello maker I got this from doesn't even monitor the temperature. She is a true artist though, amazing cellos.

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Jim Watts
http://jameswattsguitars.com

That's exactly what I was accused of when I told Anne how I was trying it.

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Jim Watts
http://jameswattsguitars.com

Thanks, Jim! Very revealing.

[QUOTE=Hesh1956] Wow, this makes some of us with the distilled wated, gram scales and digital thermometers have to wonder if we are wrapped a bit to tight...... [/QUOTE]

Hesh -

Someone has to stand up for those of us who are "wrapping tension advantaged" (or, maybe handicapped, depending on your viewpoint)

It might be that HHG is very forgiving, and it doesn't matter what the mix ratio or temperature is.

But, a single experiment where it was used without any measurement - and worked fine - doesn't prove that. Maybe Jim just got lucky - this time...

Phil

I agree with you Phil and am trying to repeat it right now.
I think the piece I was missing in the past was sizing the pieces and I really don't believe there's anything wrong with measureing every thing.
I did get laughed at however when I told about measuring with my triple beam balance, She couldn't believe anyone would go that kind of trouble to work with hide glue.
She said she didn't believe luthiers had triple beam at their disposal balance back in the 17th century and I'd just gone way overboard with this.

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Jim Watts
http://jameswattsguitars.com

Gang....

There's really no need to measure hide glue when making it, I just fill up the little cup with granuals and then level off the water and start cooking. Why would you measure something that sits at 145 degrees and evaporates constantly?? I also don't see the need to leave the granuals soaking overnight, once it's viscous it's good to go.

Now I will say that distilled or at least filtered water is still a good idea, it keeps metals and other things out of your water, even just using a bottle of drinking water would be fine. It may not be needed but I also have Saltwater fish tanks and I know for fact our water has all kinds of things in it that is not good for the tanks so I run it through a filter, can't hurt for the hide glue either

I will also say that gluing hide glue to hide glue like you did is not the best way to do it, your getting a glue bond not a wood to glue bond. If I get some time this week I'll do your experiment and the way I normally glue and see which is stronger. I'd rather see something like two sticks glued together and then weighted until the glue joint fails, that would give a better idea than pulling the pieces apart flat.

Cheers

-Paul-

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-Paul-

Patriot Guitars

I too am a bit sceptical about laying down glue and letting it gel, then adding other glue to the joint...

Maybe the second round of glue just liquified/heated up the first light coat of thinned HHG?

I always thought that you didn't want it to gel before the joint was nice, tight and not moving anymore...

Interesting.

I don't let my glue sit overnight as well. I mix mine by volume. I part granules to about 1.5 distilled water. Once the water is absorbed, I'll heat it up. I will however let it become solid (fridge) and I'll heat it up twice before using it to glue anything.Alain Desforges38948.7767013889

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I'd like to be able to prove, just for once, that money wouldn't make me happy...

Phil my friend you are right that some one has to stand up for us - the anal ones......

Heh...he said...anal....heh heh....

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http://www.presnallguitars.com

Paul,I think that as long as you get wood failure your joint is sound. It doesn't really matter how many pounds it takes to make it fail as the wood is the weak link in the chain. Also I noticed in JJ's post in the fish glue thread that he also use a sizing coat.
So I think it would be great if you did the test also. More data the better. But you won't be able to tell which way is better if the wood fails on both.Jim_W38949.0319328704

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Jim Watts
http://jameswattsguitars.com

[QUOTE=Alain Desforges] Maybe the second round of glue just liquified/heated up the first light coat of thinned HHG?[/QUOTE]
That's what I've read. In fact, that's often mentioned as one of the benefits of HHG--you can disassemble a joint and reglue without having to completely remove the old glue. The old stuff gets reactivated.

You can count me in the "anal group" as well. Perhaps it's my scientific background but I just think it's common sense to keep as much control over processes as we can. There's just too much at stake to leave critical glue joints to chance. I want to make sure that I've followed a consistent recipe and a repeatable procedure when I do any of these joints.

I consider the mixing protocol, temperature and viscosity to be EASILY controlled to the extent that I don't even have to think about it anymore. My results have been successful and I will continue to do that which has led to good results. If we get sloppy on those activities that can be controlled it's easy to get sloppy with other activities. That's not to say that if you follow a less rigid protocol you won't have good results...it's just that I KNOW that my process works every time. Isn't that what we all strive for?

As far as the sizing procedure goes, I indeed apply a very thin coat of HHG to the bare top wood where the bridge is to be adhered. A few minutes before gluing the bridge, I lightly paint on the sizing coat so it has a chance to soak into the bare wood. The thinner material seems to penetrate the wood better than the working viscosity. I then apply the working coat to both surfaces and clamp it down.

It works for me.

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JJ
Napa, CA
http://www.DonohueGuitars.com

     If you look at the structural damage from the failure test one can see about 90% of the bond exceeded the wood strength. Obviously the sizing worked! If this is worse than a non-sized bond remains to be shown, but I doubt it.

    I would be very happy with that kind of strength. The explaination that the thinned HHG absorbs deeper is plausible if not very likely.

   I learned from working with RTV that mechanically working the sealer into both surfaces before clamping helped a lot in increasing the seal strength.

That notwithstanding, I admire Jim's approach, Nobody doesn't know nothing, 'til it's tested. Thanks Jim!

Ah.... Whose guitar was that?

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Billy Dean Thomas
Covina, CA

"Multi famam, conscientiam, pauci verentur."
(Many fear their reputation, few their conscience)

[QUOTE=Sprockett] Gang....

I will also say that gluing hide glue to hide glue like you did is not the best way to do it, your getting a glue bond not a wood to glue bond.
Cheers

-Paul-[/QUOTE]

One nice thing about hide glue is the way heated glue melts into previously applied and cooled hide glue to make a new joint.

[QUOTE=Marc] One nice thing about hide glue is the way heated glue melts into previously applied and cooled hide glue to make a new joint.[/QUOTE]

Yep, it is an old trick that antique furniture restorers use on original pieces that have developed loose joints after a few hundred years and are too valuable to compromise by dismantling. The joint is injected with thinned hot glue and heated or it is steamed with no new glue being applied, the old dry glue reconstitutes and bonds like new.

I have tried this myself and it works well, but I could not tell you if it is as strong as a new joint with fresh glue. Maybe this time it is only 50% as strong and therefore will only last for one hundred years this time. Pretty pitiful really don't you think

Cheers

Kim

Kim, i love your since of humour Man!

Jim, thanks for the post. It gives me something to think about, as if I need more. JJ's hypothesis of the deeper penetration at less viscosity does sound plausible.   

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Don Atwood
Arlington, VA

Now, what am I going to do with my digital scale? Sometimes I think we make things too complicated.

[QUOTE=vpelleri] Now, what am I going to do with my digital scale? Sometimes I think we make things too complicated. [/QUOTE]

I use mine to weigh every component that makes up the guitar...braces, plates, bridge, etc. Just more data points to measure and record. They don't make much sense to me right now but may be more revealing later. In general, I think lighter is better.

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JJ
Napa, CA
http://www.DonohueGuitars.com