Re: Out XXX rated

[Tom Jennings <tomj@xxxxxxx>]

On Sat, 9 Apr 2005, Armand Eshleman wrote:

> It would appear to me that some where some how incompatible substances got
> together there and caused a reaction
> which softened the parent surfaces. If red RTV is the only compound you used
> to reinforce the parts then for some
> chemical reason the plastic that the parts are made of don't like RTV. If
> you used another compound even to clean
> the area that in conjunction with RTV may have caused the melt. It sure
> doesn't appear as though sunlight or heat
> caused the damage. I have had plastic (usually styrene) in contact for long
> periods of time with rubber and/or vinyl
> do the same thing. I don't believe that the dash parts are styrene but never
> the less it is a chemical reaction that caused
> your problems. May be if you tried something like JB Weld which seems to be
> amazing stuff, and I have never had it
> react negatively with mating compounds

I'm sure you're right. I've used the same set of chemicals to do
this car and most others, and it's been fine; the lucite insert I
think I used the red RTV.

* purple degreaser
* dish-washing soap & water
* sandpaper, etc
* JB weld and/or PC7 epoxies
* occasional superglue (bits and pieces)
* SEM: vinyl prep, plastic prep, sand-free, paints
* clear and black "regular" RTV.

I may or may not take it out this weekend (my new trans wasn't
ready Friday; will pick up Tues or Wed) and I'll examine it.

I know I used that red RTV in a couple of small spots inside the
gauges; to hold the gels onto the metal dial cards. I don't see a
problem in there; there's something about the injection-mold
plastic.

Also, in that bad photo, the lucite part I degreased, scrubbed
with a soft brush to remove the old paint, re-painted, then
carefully 1500-grit polished the raised letters; it failed in a
really strange way, it looks exactly like 75-year-old paint, sort
of crazed, and flaked of in shrunken flakes. Whatever happened was

pretty extreme.