Loctite RC-680, anyone have experience?
Has anyone used Loctite RC-680 to gap fill a loose headset cup/head tube seat? If so, is it possible to later remove the cup without applying paint-damaging heat once it's cured?
I have an '89 Bridgestone MB-2 that, being a full rigid MTB, has a very slightly out of round head tube due to pounding. In the past, I've used Loctite 242 to gap fill, but 242 is a weak gap filler. I'm looking for a stronger compound, but I don't want to use anything that will create such a strong bond that the cups can't be removed mechanically. The bike is something of a classic, and I want to preserve it's original finish.
Barnett's mentions RC-680 as a solution, but Loctite's 680 data sheet indicates heat should be used to break the bond.
Most of Loctite's gap filling bearing and sleeve setting compounds are very strong (they have to be to work properly) so they will require heat to break the bond.
One approach is to buy a high quality headset with removable cartridges bearings such as a Cane Creek, FSA or even Shimano's Ultegra level HP-6400. Since the cups and crown race see no wear, a worn out headset only requires new bearing cartridges and the cups never have to be removed. Chris King obviously makes a high quality headset but the bearing cartridges are spun into the cups and can't be removed so it isn't an option.
i have used 609 on loose lower cups(cup pushes in with hand and falls out with gravity)