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From: jackh@zehntel.UUCP (jack hagerty)
Newsgroups: net.auto
Subject: Re: The worlds best gasket cement.
Message-ID: <1812@zehntel.UUCP>
Date: Tue, 9-Apr-85 13:43:08 EST
Article-I.D.: zehntel.1812
Posted: Tue Apr  9 13:43:08 1985
Date-Received: Thu, 11-Apr-85 00:42:19 EST
References: <231@sdcc12.UUCP>
Organization: Zehntel Automation Systems Inc, Walnut Creek CA
Lines: 34

> Any color silicone rubber cement will do, but I
> prefer white, because that makes it easy to see the thickness of the film,


Not true!  Silicone rubber is wonderful stuff, but it comes in different
compositions for different purposes and use of the wrong one could be
disasterous.

The clear and white types are sold as "bathroom caulk" or "glass sealer"
and are good for just that. Around a car they can be used to seal leaks
in your doors, windshield, trunk, etc. but they don't have the heat and
chemical resistance to be used around engines.

To seal oil covers, you need "engine gasket" type silicone. The one marketed
by Permatex is blue (I say marketed because it's actually made by GE). This
type is temperature resistant up to 400 F and also resists oils and other
automotive chemicals. For higer temperatures, such as sealing exhaust systems,
etc., use "High Temp" silicone. This type is colored red and is resistant
up to 500 F. Some confusion is possible because GE's color for their "normal"
engine silicone is also reddish orange. Be sure that any silicone you buy
for this purpose is clearly marked "High Temp".

GE has also come out with a very specialized type of silicone recently. It
is a clear, glass sealer type, but the twist is that it's "flowable". It 
seems to be the same gooey stuff as any other silicone, but the surface 
tension is very low and it continues to run and flow into tiny cracks and 
holes. I used it last fall to seal an 8 year old leak in my Alfa's doors 
(that had resisted all conventional sealants including standard clear
slicone). It was wonderful, not a drop all winter!


-- 
                    Jack Hagerty, Zehntel Automation Systems
                          ...!ihnp4!zehntel!jackh