> From:    Rob <becida@COMCAST.NET>
> Date:    Sat, 2 Jun 2007 16:06:24 -0700
>
> RTV and other gasket 'stuff' comes in a variety of colors. I've used
> different colors for the same job with no noticeable problems.  [...]
> Any thoughts on the different colors?

Nominally, the different colors have slightly different applications -
higher temperatures, more resistant to fuel/oil/whatever, etc.  Some of
this is probably true and some of it is probably a way to sell more RTV.

The colors I've personally used around various cars are the blue stuff,
the red stuff, and the clear stuff.  The blue stuff seems to be a
reasonable default for things that don't get screamingly hot -
transmissions, wheel bearing housings, stuff like that.  The red stuff is
for things that you think are too hot for the blue stuff - but it's
probably still not good enough for exhaust manifolds and similar
applications.  The clear stuff doesn't go on the powertrain at all, but
is good for sealing around windows and such, if the gasket is only
slightly damaged or if it's a non-stock window (think trailer or
conversion van).

Permatex was an early supplier of RTV sealants and their color code is
somewhat of a standard.  Their Web site
http://www.permatex.com/products/automotive/automotive_gasketing/gasket_makers.htm
shows most of the common colors.

For grins, take a look at their old advertising booklet at
http://www.permatex.com/documents/1937MarionAssemblies.pdf .  In 1936,
they took apart a brand-new Ford V-8 and put it back together with their
goop.  "The twenty-eight solid gaskets not used were made of paper, cork
or composition and represented a value of $1.41, compared with 25 cents'
worth of Form-A-Gasket Number 2 that was used."  (That's an average of
a nickel per gasket in 1936 money.  In 2006 money, that's about $20 for
all the gaskets, an average of 71 cents each.  The No. 2 would be about
$3.50 in 2006 money.)  They then drove the car over *twenty thousand
miles* without anything leaking!  OK, in these latter days when you can
buy a cheap car with a 100,000 mile warranty, that seems silly, but I
guess it wasn't too bad for 1937.

Standard disclaimers apply; I don't get money or other consideration
from any companies mentioned.

Matt Roberds