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Spreading HHG
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Author:  Mark Tripp [ Wed Apr 05, 2006 4:40 am ]
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OK, I'm just starting to use HHG. I understand that I can just run a bead on things like braces, but how do you folks get even coverage on larger areas like neck and tail blocks? Brush it on? Spread it with an ink roller or finger? Or do you use some other method?

Want to do blocks tonight when I get home from work, so thought I'd check with the troops before I went about it willy nilly!

-Mark


Author:  Michael Dale Payne [ Wed Apr 05, 2006 4:57 am ]
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Glue brush. get everything set up and ready. you can brush on and get in place before the hhg starts to jell.

Oh and preheat the block helps

Author:  Cocephus [ Wed Apr 05, 2006 7:32 am ]
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I`m making the move to HHG myself and have one more question. I`m aware of getting set up, making dry runs, and warming things up to help buy assembly time, but what can one do if he gets in a jam and needs just a little more time? More heat from, say a hair drier, or is it done and needs to be disassembled and reglued?

Author:  Michael Dale Payne [ Wed Apr 05, 2006 7:50 am ]
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My opinion is once the hhg starts to jell the best pollicy is to remove it. theoreticly though if you could get the hhg back to 140 what you say would work but I think in an open atmosphere this would be hard to pull off

Author:  crowduck [ Wed Apr 05, 2006 8:08 am ]
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Not my personal experience, but I've read that it can be saved if starting to gel with a heat gun or hair dryer. I'd experiment with some scrap, in fact I think I will. To buy more assembly time, I bought a food warming tray, a big one 12"X18" with a temp control, got it at a thrift shop for $5. I just put my parts like braces, etc. on it for about 5 minutes to get them nice and toasty.

CrowDuck

Author:  RussellR [ Wed Apr 05, 2006 8:27 am ]
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Chris

I meant to ask you before, you don't have a pic of your tray do you, I'm struggking to envisage what it is.

Thanks

Russell

Author:  JJ Donohue [ Wed Apr 05, 2006 9:24 am ]
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If it gels before I make contact with the 2 surfaces, I remove it and start over. I work faster so that it doesn't gel.

Warming the surfaces before application and contact is key for me. I heat braces, blocks, bridges and other small parts in a microwave (15-30 seconds). If you can't hold the piece coming out of the microwave, it's too hot. My tolerance for heat is 140*. I heat the rims and gluing surfaces with a hair dryer before applying HHG.

But most importantly, practice dry runs and work fast?


Author:  crowduck [ Wed Apr 05, 2006 9:28 am ]
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Russell,

Not sure if these things are common to the UK. But they are/were used in the US at the dinner table to keep foods warm. Here's an eBay listing for one similar to mine. Maybe try eBay UK.
Another nice thing is that I keep it plugged in right on/next to my workbench, and I keep a bowl of heated water there too, for cleanups.

CrowDuck

http://cgi.ebay.com/VINTAGE-GlassTop-Salton-FOOD-WARMER-HOT- Tray-MEDIUM_W0QQitemZ4452037566QQcategoryZ20685QQrdZ1QQcmdZV iewItem


crowduck38812.7729050926

Author:  RussellR [ Wed Apr 05, 2006 9:39 am ]
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Thanks Chris

Yes they are/were common I know it as a hot plate, thank for posting the picture Chris, that is a great idea.

Russ

Author:  Mario [ Wed Apr 05, 2006 11:15 am ]
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For spreading it around on large parts like blocks and such, I use the bottle's tip. Messy, but the glue cleans up so nicely...

KISS

Author:  Alan Carruth [ Wed Apr 05, 2006 11:30 am ]
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I tried the bottle, but went back to using a soft brush. Different strokes, literally....

I mix my HHg fairly thin: IMO luthiers don't need to make it as thick as the cabinet guys do, since we don't use the sort of clamping pressures they use. This gives you a longer working time, but you have to remember _not_ to clamp it too tightly. What counts, I think, is how much actual glue solids end up in the joint, and that's a product of the mix, the heat, and the clamping pressure.

Some folks use a _very small_ amount of the Franklin's 'Liquid Hide Glue' in their mix: like a couple of drops in a baby food jar full (what, you don't mix yours in a baby food jar?). FLHG contains a chemical that keeps it from gelling at room temperature: possibly thiourea. Although they claim that it works 'just like' HHG, everybody I know that has tried it has found it to be hygroscopic, so things tend to fall apart in high humidity. My experience, which in not everybody's, suggests that it also tends to break down with age in the bottle. Never use this stuff 'straight' for anything that you want to have hold together! However, a little tiny bit in the regular mix will extend the working time without seriously effecting the strength or longevity of the bond, it seems. You can get the same results with plain urea, but that certainly does break the glue down over time in the pot; it may not hurt it once it's dried.    

Author:  crowduck [ Wed Apr 05, 2006 2:05 pm ]
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I read somewhere that 'old timers' would add a bit of urine to HHG to extend open time. Maybe a 'wives tale', never know until you try it.

CrowDuck

Author:  Rick Turner [ Wed Apr 05, 2006 3:10 pm ]
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Well, the piss is urea as per Alan's post. Yes, it will extend the life, and your guitars will smell nice, too.   Piss on the top for that nice vintage look. Bleed on it for a sunburst.

Small glue bottles kept in the glue pot full of hot water or microwave right before use.   

Chris, I like that warming plate idea there...very nice.

You can also use infra-red bulbs...heat lamps, to warm the parts.   Remember the scene in the violin maker's shop in "The Red Violin"?   there was a fire place and a brick wall that kept that part of the room very warm. That's where they would have done their gluing.   In the old Martin factory, the workers would heat the wood parts on the old steam radiators that heated the whole factory.

Author:  Mario [ Wed Apr 05, 2006 3:38 pm ]
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I tried the bottle, but went back to using a soft brush

I tried the brush, would never go back. <g> There's no way we can dip a brush once and spread the glue around an entire guitar's ribs, and both blocks, to glue the top or back, in one shot.

Yet, when I had a student here in December, without my knowing it, and without me rushing at all, he watched as I ran a bead of hide glue all around the linings, then placed the back on and clamped it in place with go bars, in around 40 seconds. We then spent the next minute cleaning up the tiny amount of squeeze-out there was. He was impressed, to say the least! Even I was impressed at the time frame, having never really timed it. Later that day, we did the top on the same body, and again, the time was about the same.

No way a brush can do that; you'll simply run out of glue in the brush too often. Dipping the brush in the load new glue just takes time, time you don't have.

I'd be ready to bet that the reason you didn't like the bottle was because you like your glue thin. Mine barely runs from the bottle, and is very easy to control.....

Not a single failed joint(not counting two bridges) in 6 years of using hot hide glue. Not one.

Author:  RussellR [ Wed Apr 05, 2006 6:37 pm ]
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I haven't been using hide glue for long, but I love the stuff, and I like to use a bottle too.

Mario 40 Seconds now that is quick !

I have been testing trying to use for joining the plates to the rim, but I get too much squeeze out, guess I need my glue a little thicker and to judge the bead size better.

The other thing I have noticed is when I join my tops with hide, the join is much more noticeable that it was with tightbond, Is this the experience of your guys ?

When I use tightbond I struggle to find the join, but with hide there is is a very faint but distinct line. RussellR38813.1522222222

Author:  Mario [ Wed Apr 05, 2006 10:41 pm ]
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You're doing something wrong; a hide glue'd top join is all but invisible. Much, much more so than Titebond!

Unless you're using really low grade, dark glue?

Author:  RussellR [ Wed Apr 05, 2006 10:54 pm ]
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Thanks Mario

I am wondering about the Glue, I got it from a luthier supply place but the granuals are see through but with a quite brown tint, the mixed glue is almost tofee colour.

Is this right or have I got very dark stuff ?

Author:  Bruce Dickey [ Wed Apr 05, 2006 11:50 pm ]
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[QUOTE=Mario]


I'd be ready to bet that the reason you didn't like the bottle was because you like your glue thin. Mine barely runs from the bottle, and is very easy to control.....

.[/QUOTE]

Well, that's quite thick hide glue then. Definitely not maple syrup thin. Will have to thicken mine up a bit just to try it. Last couple of tops I did fairly maple syrup thin and it concerned me that there wasn't enough glue in there. Titebond was always quite thicker by comparison to Hide.

Author:  SStallings [ Wed Apr 05, 2006 11:53 pm ]
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What mix ratio do people use. I mix mine per the Behlens hide glue (192 g) instructions which say 1 part water to 1 part granules by weight. Comes out pretty runny. Frank Ford's article, however, says 1.9 water to 1 part glue. Am I missing something?

Author:  Alan Carruth [ Thu Apr 06, 2006 6:54 am ]
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SStallings:
You're not exactly missing anything, it's just that using hide glue is not an exact science.

Again: what counts in the end is how much dried glue there is in between the two pieces of wood, and whether you got it all clamped up before the stuff gelled. Glue itself is not a strong material. It's too brittle, for one thing. What's strong is the chemical bond between the glue and the wood surface. What you want, then, is pretty much a minimal amount of glue; just enough to ensure that there's some all the way through the joint, holding the wood surfaces together chemically.

There are all sorts of ways you can end up with that amount of glue in the joint. Cabinet makers tend to mix the glue pretty thick. They often have to use a lot of clamping force to pull slightly warped pieces of wood into line, and need the extra 'body' so that all of the glue isn't squeezed out in the places where there is good contact without the pressure. Also, when you're cutting a complex joint like a full dovetail it's hard to get the fit to be 'perfect' everywhere, and if it's too close the swelling from the water in the glue might well preclude assembling the parts! So a thicker glue, that can act as a filler, is helpful. The big problem with thick glue is that it gels at a higher temperature, so you need to keep your gluing area warm.

In our work we _can't_ use the kind of clamping pressure cabinet makers do most of the time. With the thin parts we'd just crush stuff. We rely on getting a perfect fit, and then using the minimum of clamping force to just hold things in place while the glue sets up. If you mix your glue too thick you just won't squeeze enough out a lot of the time, and end up with a weaker joint. I've made 'rubbed' top and back joints on many of my arched instruments; just spreading on the glue and rubbing the parts to force out the extra. When they are about to 'grab' you slide the parts into alignment, and leave them, with no clamps at all. The shrinkage of the glue does the rest.

Hide glue is just unrefined Jello. Once it gels that's the structure of the joint: once you cut a piece of Jello it won't stick to the rest. If you move the joint after the glue gels, you've broken it, even though the stuff is so soft, and the only ways to get it to go back together are to reheat it or start over.

Mario: Maybe I'll try a thicker mix in the bottle. 40 seconds sure sounds good....

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