Mike Knudsen wrote:
In article om, "Joe Curry"
writes:

No matter what you use, it will have to handle the heat. It is not clear
that the cyanoacrylic materials (such as Crazy Glue) will hold up under the
temperatures to which power tubes are subjected.

Red silicone RTV is great for tube bases and for caps, even on power tubes
that run very hot. However, it's also very expensive compared with the
standard cements. Fine if you are doing one or two tubes, not so fine if
you are on a production basis turning out thousands. But great for repair
work, and available at the auto parts store.

I have never had cyano glues (Crazy, Super, etc.) hold *anything* together for
any length of time, even at room temps. I've come to consider these glues as
one big consumer fraud. Certainly don't work on plastics. --Mike K.

Cyanoacrilate glues are very strong in expansion mode. You can cement two
things together and put a heavy force pulling them apart and they will stick
very effectively for a long time, even when wet.

They are very weak in shear mode. Even a very small amount of shear force
across a cement join will cause it to fail eventually. Sometimes that
eventually is in a few hours. Almost every application where you would be
using cement involves some shear force.

They also do not fill voids at all, even the fancy "gel" types. You need
a VERY clean mate between the two surfaces. Even a slight bit of surface
roughness will dramatically weaken a join.

The cyanoacrilate stuff is very effective for a few things, like rubber
O-ring belts. For most things, though, it is a temporary fix at best.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."