HHG Clamp Time

[Lillian]

How long do you keep a HHG joint clamped? I have my first top jointed and glued. While I'm itching to keep moving, I don't want to unclamp it too soon.

[Bob Connor]

About 4 hours Lillian.

[Lillian]

Thanks Bob.

[Hesh1956]

What Bob Said.

[matthew]

what Hesh Said?

[sebastiaan56]

What Mathew, Hesh and Bob said.....

[Lillian]

Jeeze, all these different opinions. How am I supposed to sort this out!?


Thanks guys. Its go at least another hour to go. In the mean time I need to spend some quality time with the drum sander and figure out how to get the paper on tight enough to stop the divot down the center.

[Dave White]

Lillian,

Interesting question - so just to give you even more confusing options . . . Some "technical" websites I've seen give 15 hours as the clamp time for hhg (same as fish glue). On joining tops/backs I use the tape/tenting method with hhg and take the tapes off after about 45 minutes to let the moisture evapourate more easily. The joint is clamping itself after this - as that's what hhg and fish glue do as they cure With braces glued in the go bar deck I usually leave them between 1-2 hours depending on how impatient I feel. The only one I leave a really long time is the bridge which I usually do in the evening and leave it clamped up over night. I suspect I could unclamp after a couple of hours though and it would still be fine.

No major stress (either for the builder or the joint) though for quite a long time after this.

[Lillian]

Thanks for the input David. I had read that it should stay clamped for 12 to 24 hours, but thought that was overkill. I like your numbers better.

About how long is "quite a long time" before joint stressing? A day, three?

[Dave White]

Lillian,

Well how long's a piece of string The bridge is probably the most stressed joint. I glue it in the evening and then do the set up the next morning. So it's glued at say 6pm and goes under string tension for the first time at around midday the next day - so that's about 18 hours. But in terms of things like the top, there's not a huge amount of stressful things you will be doing to it after jointing - rosette, thicknessing, bracing etc. For braces, I have carved them in the past straight after taking the go bars off after 1-2 hours. Now I don't usually carve until I'm ready to close up the box, so my impatience gets catered for by all the other things that I have to do.

As the hhg joints take time to fully lose moisture and cure it's sometimes a good idea to leave the tops joined for a few days or so or longer before thicknessing, but if impatience gets in the way it's not such a big deal.

[Lillian]

Thanks David. From you comment I had envisioned needing to let the bridge sit for days before stringing it up. I didn't have a problem with the concept per se, but was worried that I might jump the gun and have the bridge tear off after stinging it up. I'll add you words of wisdom to the bridge folder.

Thanks for filling in the details for me.