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Another HHG question
http://w-ww.luthiersforum.com/forum/viewtopic.php?f=10102&t=5363
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Author:  Daniel M [ Tue Feb 28, 2006 5:44 am ]
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OK, so I bought some HHG from Shane & the hot pot is on its way. I've got an old hair dryer to warm up the parts.
So, given I'm in a warm room with warm pieces of wood & the glue is mixed correctly, How long DO I have to get the glue on & get the parts clamped together?
Is the glue spread on both surfaces?
Anyone got an Ativan???
I assume there's no way one would have time to do a rope or rubber strip lashing to glue on a back or top using HHG. The go-bar deck might be quick enough with a protective strip around the edges.
Any sugestions???
Thanks,   Dan

Author:  crowduck [ Tue Feb 28, 2006 7:19 am ]
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Dan,

'Open time' depends on the 'gram weight' of your HHG. Assuming you have 192 gram wt. in a warm room it will gel in about 30 to 45 seconds. Do an experiment in your shop environment, and time it to know for sure.
I'm working on a scheme using a form matching my top & back cutout of 3/4" ply or MDF with a 1/2" strip of cork or rubber around the perimeter that's thick enough to accomadate the dome of the back or top. After spreading the HHG on the head, tailblocks, and ribs, drop the top/back on and align clamping with cam clamps at the head & tailblock only, then apply the 3/4" form(cutout to accomadate the cam clamps), and either use go-bars, or weights like bar bells to complete the clamping.
What's an Ativan?

CrowDuck

Author:  Bruce Dickey [ Tue Feb 28, 2006 7:39 am ]
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My first hide glue experience was in 1999. I went to Titebond yellow 'til now and just finished the braces on the OLF #2 Top. Let me say one thing about hide glue:

IT SURE IS MESSY!

But it works.

Author:  Serge Poirier [ Tue Feb 28, 2006 9:35 am ]
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I use 260g and i had plenty of time to spread the glue on both surfaces when joining tops and backs, of course, i did dry runs first but didn't expect HHG to be so messy, i'll probably have to play with the recepe for desired thickness but i still enjoyed the experience of the quickest and strongest adhesion ever!

Author:  crowduck [ Tue Feb 28, 2006 10:09 am ]
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Messy, but the nice thing is it cleans up easily with just some warm water.

CrowDuck

Author:  Dave Anderson [ Tue Feb 28, 2006 2:02 pm ]
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Dan, What kind of glue pot did you get? Here's a pic
of the new one I got off E-bay.It works real nice and keeps the temp at 145.

Author:  mikev [ Tue Feb 28, 2006 2:23 pm ]
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yeh dan, I hope you didn't buy one of those expensive glue pots. If so send it back, I got the Hot Pot at walmart for $9 with tax. It wasn't the rival one everyone recommended, but it looked exactly like it. Keepes my glue at 145 at about 1/3 of the dial..
Mike

Author:  Daniel M [ Wed Mar 01, 2006 5:29 am ]
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No-one in our small town sells the small Rival, (or any small pot with a rheostat adjuster... only 2 position "warm & "cook") so a friend in the City is sending me one.
Thanks for the input guys!
I'm looking forward to trying the stuff. I have an old Braz back which I have glued up twice, once with Yellow Glue & once with medium CA. both times the joint failed when I flexed it to test the joint. A clean break at the glue line both times. Hopefully the hide glue will work better.
Maybe I'll try epoxy while I'm waiting for the pot to arrive.
Dan

Author:  Bruce Dickey [ Wed Mar 01, 2006 11:01 pm ]
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[QUOTE=Daniel M] I have an old Braz back which I have glued up twice, once with Yellow Glue & once with medium CA. both times the joint failed when I flexed it to test the joint. A clean break at the glue line both times.
Dan[/QUOTE]

Why would you flex a back join before putting on the back graft? That seems silly to me Dan. You just wasted your effort....... twice.

Now if it busted just lying around that's different. I bet I could get most back joins to fail before the graft. Common Sense is free, but you have to use it.

I wish I had some Braz to flex.....

Author:  Shane Neifer [ Thu Mar 02, 2006 4:22 am ]
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Dan,

I tried gluing my back on with hide glue. After adding more to areas that set before I could clamp, after the forth "extra shot of glue" it was finaly down. I think that John Mayes said earlier "I am working on getting faster with this glue but until then I use hide glue for the braces and titbond for gluing the back and top". That is what I did! For the top I used Lee Valley Cabinetmakers glue for the along the kerfed linings as it has a long open time and then I spread hide glue on the tail and heel blocks and dropped the top on, clamping over the blocks first. I notched my braces into the linings so they had a very accurate indexing point. The top went WAYYYYYY better. The hid glued on the blocks should help to slow down the 'creep' that may occur with the PVA/AR glue used elsewhere. With hide glue just put it on one surface. I have found the best method is to put the glue on the brace, put the bace onto the top/back and just push it down and hold it there for about 30 seconds then start to brace it. Otherwise you end up with the glue not fully squeezing out and drying while holding the brace off of the back/top.

Shane

Author:  j.Brown [ Thu Mar 02, 2006 5:38 am ]
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No need to spread glue on both surfaces. Use more than you think you need on one surface and just let it ooze out when you clamp it. In about 5-10 minutes, it will gel up and you can peel it right up with a flat, sharpened piece of wood.
It looks like it'll be messy at first, but clean up is such a breeze. The "reversibility" of it is amazingly easy as well.
At first I was afraid of it, I have to admit, but it is becoming easier and easier to use and I love the stuff.

-j.

Author:  Daniel M [ Thu Mar 02, 2006 3:41 pm ]
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Hey Bruce; It may be silly to overflex a joint to test it, But i always gently flex test top & back joints before I continue to work the plates. This is the first time a joint has failed on me. Seems to me that if the joint fails cleanly along the entire length with a gentle flexing, it would probably fail sometime down the road.
I'd rather redo it now than after the instrument is finished.


Author:  Serge Poirier [ Thu Mar 02, 2006 3:45 pm ]
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Good point Dan, i almost slapped my face after doin' the same on my first tops and backs joints last week and thought to myself" what are you doing?" then realized it was the natural thing to do to feel more secure...so thanks, i feel i'm not alone doing that!


Author:  crich [ Thu Mar 02, 2006 3:51 pm ]
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I did too,also. I glued my top twice with HHG and they broke easily down the seam. I finally gave up and used TiteBond Original,it passed the test. Clinton

Author:  Mattia Valente [ Thu Mar 02, 2006 7:42 pm ]
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Well, quite. I flex my joined tops, and the glue line holds, as it should.

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