Official Luthiers Forum!

I don't have any experience with HHG, but could the problem be with the water used to mix it? Maybe a higher mineral content?

Alex

_________________
"Indecision is the key to flexibility" .... Bumper sticker

I always mix mine with distilled water

_________________
Steve Smith
"Music is what feelings sound like"

It was distilled water...

Sounds like mold, but overnight?
Any chance of steel wool in the vicinity?

_________________
https://www.facebook.com/profile.php?id=100008907949110

There are lots of variables which could play in to this (various contaminants, ratio, etc), but it sounds to me as though it may have simply gotten too hot for too long.

Collagens go through various stages of denaturation. It's been a long time since I've studied this in depth, but going from gel to liquid would be secondary to tertiary stages (primary would be the cross-linked solid, and quaternary means broken down proteins which will never recoil). Bring it just past the brink to the tertiary liquid state where the proteins uncoil, and it can recoil and recover to the secondary gel state. Bring it too far beyond reasonable, and the proteins will break and no longer coil back up to return to gel state.

Key is, most folks think in terms of temperature alone, but time is an equally important factor. We often use the rule of keeping our glue pots around 145°F, and this generally works fine. Even at this temp however (or any temp above liquid phase), the proteins are breaking down - higher the temp, the faster they break. Keep a pot at 145° For a few days, and it will break down enough to no longer recoil and gel at all (and provide less strength to the joint). Push that temp up to 165°, and it may take only a few hours to reach this state.

You can push temp up briefly before applying for a bit more working time without any serious effects, but if kept high for long it will break down the proteins and deliver results like what you observed. There's actually nothing magic about the 145° rule we use, but rather it's simply a good average compromise between working time and pot life.

Your "167° lid on" leaves me to wonder if it may have simply broken down too quickly if you had the lid on for too long (and I assume you're using a double boiler approach). If this is the case, then your confidence in the joints may depend on whether you used glue from an early or later point in the life of the pot.

_________________
Eschew obfuscation, espouse elucidation.

I had a batch of bad water once. Try a new bottle of water from a different company. Nothing lost trying this.

Jim

David, thanks, that makes sense...

Jim,

Perhaps I'll switch to Evian so I can use the rest for Scotch...