Re: glue

Bob Madden (madden@netcom.com)
Tue, 18 Apr 1995 21:15:19 -0700 (PDT)

Dean, I have been responsible for equipment in a thermal envoronment which were placed on the back end of missiles. RTV is used to protect against that environment. I myst admit it was a two part glob and the refrigated until needed (with a longer shelf life). The surface preperation is very important and the atmosphere in which the cure takes place, particularly humidity. Once the bond is successfully developed it is really good. We have had returned units 20 yrs old with good adhesion. But I'll say this a technique that results in a bad bond is terrible to solve. Thank goodness I only had to do it on one product. It is like the curl in the middle of the little girl's forhead. If she is good she is very very good, but if she is bad she is horrid!

Bob

):-{])) <---- madden@netcom.com madden@svpal.org Remember amateur astronomers: "keep looking for the next Universe"

On Tue, 18 Apr 1995, Dean Ketelsen wrote:

> What? You don't trust silicone RTV to hold your mirror? We use it
> to hold our 20 ton, $4 million, 6.5 meter casting on edge for 6 months
> while we clean out the mold material from the glass. It is the same
> Silicone RTV with the acetic acid smell you have been talking about
> for the last few days/weeks. YOu would be suprised how strong it
> is before failure, typically it will sag 4X the bond thickness before
> yielding. The problem may ultimately be in holding the optic without
> sagging and the resulting collimation/focus problems others have
> touched on. I have not seen a failed bond using RTV, have others?
> -Dean
>