HHG and open time

[rocket]

In the past i've mostly used Titebond for guitar construction and only used hhg here and there, but recently Frank imported about 3 ton of the stuff and i went halves with him, so i think i've got enough to last me quite a while.
So, with my current build i've only been using the hhg, and as most of you already know, easy to use and easy to clean up. To give myself a bit extra open time i warm the two surfaces with a heat gun first then apply the glue, so far so good.
My question is, when gluing a larger section like top to sides is it just a matter of warm surfaces, apply glue and go like hell and hope you get the top positioned properly before the stuff starts going off, or is there some sneaky technique that some of you use to stay inside "open time".

[kiwigeo]

One option is to apply glue and then whack the top on and then go around with an iron or a photography studio style electric iron and reheat the glue and secure the joint. This is how Lundberg attached his lute tops.

[Kim]

You can use HHG for gluing the top to the sides. The main consideration is to have everything ready and practiced with dry runs. Once you are confident you have it down pat, apply the glue and work methodically and efficiently...and hope to hell that nothing goes wrong. Alternatively use tight bond or better still, fish glue for this part of the build and save yourself the stress. As much as I am a huge fan of HHG, I see no practical or tonal advantage to using hide glue over any other for this particular part of the process.

Oh and by the way, if you still want to use HHG it may help to take the glue temp up a good bit more than the prescribed 140f...that is good working point but within reason, going hotter, will not effect the glues strength whatsoever regardless of what popular hearsay will have you believe.....don't forget, they need to 'boil' the crap out of the dead animals to extract the collagen in the first place...so don't be afraid to get the glue good and hot when you need to for the job at hand.

Chill

Kim

[matthew]

On a double bass, which is a LARGE plate to glue to the sides, I either

1. clamp the top in position with a bunch of spool clamps, then loosen three at a time, work a little HHG into the seam with a palette knife, reclamp and then remove the next few clamps, etc ...

or

2. Prime both surfaces with HHG. When dry, clamp the pieces together. Using a steamer, or brush and hot water, run around the seam to remelt the glue. tighten up.

Some luthiers mix a little urea into the glue to extend the open time without adverse results.

[jeffhigh]

It can be done fairly easily if you use go bars
There is a video on Youtube showing Mario Proulx doing this but I can't find it now
I have done this on one guitar but it is a bit stressful and I dont see a real advantage over titebond for this.

[WaddyT]

The key is not to waste time. I have watched Mario's video a number of times, and when you watch, he never hurries, however all of his work is choreographed and deliberate - no wasted motions or do-overs. He guides his glue bottle with his other hand to keep it putting glue in the right places. He applies glue twice, as that retains heat better. He also pre-heats his back and his linings. I'd say he does it with practiced discipline.

[Allen]

Move to the tropics. My glue up room is regularly over 40 degrees with the dehumidifier running. All the open time you want.

Once you get the two surfaces together, you've got a lot more time to get clamping pressure on. And if you're unsure at all, once you do have everything clamped up, you can always go around with the heat gun and warm the joint up again. On my last Weissenborn is did like Matthew describes and it worked a treat. Though I primed both mating surfaces and let dry as well.