[DeTomaso] Ultra Copper RTV and O2 Sensors- Esoteric Details Explained -Annealing, Dead Soft, And Other Answers You Didn't Know You Didn't Know

[Chris Difani]

Paul:

So you'll be able to amaze your friends at your next cocktail party, when 
the subject of "dead soft" aluminum comes up (as I'm sure it does). Dead 
soft usually refers to the "hardness" quality of a metal, and is used to 
describe a certain condition within the very general headings of "annealed" 
or "heat treated".

When metal is "annealed", it is treated by either heating, or cooling to 
certain temperatures (depending on the metal and it's alloy).  The goal of 
annealing is to "...make the metal softer, for improved machinability; to 
improve or restore ductility for subsequent forming operations; or to 
eliminate the residual stresses and microstructural effects of cold 
working..." (quoting from the 27th edition of the Machinists Handbook).

In steel fabrication, a common procedure after welding steel tubing into a 
roll over protective structure, is to heat each weldment, and the nearby 
area, to cherry red, then let it cool slowly to room temperature.  This 
"heating to cherry red" is hot enough that the steel molecules can move, and 
align themselves throughout the heated area.  This allows the stresses in 
the joint to be relieved, and makes the strength of the joint much more 
uniform overall.  Some people use heat treatment furnaces to anneal a 
structure like this.  In the airplane industry it was common practice to use 
an oxy-acetylene heating torch to perform this heating process on steel 
tubing fuselages.  There's been tests done between the two systems, and the 
results showed that there wasn't significant difference between the two 
methods.

Usage of the term "dead soft" applies to aluminum, and it can vary depending 
on who's using it.  Normally when the term "dead soft" is used in relation 
to aluminum, this means that the metal is almost pure aluminum, one of the 
1100 alloys, and has not been heat treated, cold treated, or had any machine 
hardening process applied to it.  The metal is as soft as any heat or cold 
treatment can make it.  There is no "softer" state of the metal known.  The 
metal will have no "spring" to it, or any other characteristic that relates 
to hardness.  It's not brittle, tempered, or anything else, except for being 
as soft, as ductile, as modern metallurgic science can make it.

Which means it should be just about perfect for being squashed between two 
harder surfaces, and conforming to any and all irregularities in those 
surfaces.... like being used for a filler material, for a gasket.

And that's pretty much what "dead soft" means when we're talking about 
aluminum, or other modern metals.

Chris

Chris Difani
'73 L #5829 "LITNNG"
The Electric Pantera
Sacramento, CA
Email: cdifani at pacbell.net







----- Original Message ----- 
From: "P. Rimov" <rimov at charter.net>
To: <scottcouchman at yahoo.com>; <detomaso at realbig.com>
Sent: Friday, February 13, 2009 7:03 PM
Subject: Re: [DeTomaso] Ultra Copper RTV and O2 Sensors


> Have your header's flanges milled/machined level and use a good set of
> quality gaskets like Percy's dead soft aluminum multi layer gaskets and
> problems you wont have. Percy's dead soft (no idea what on earth dead soft
> refers to) multi layer aluminum gaskets are by and far the best sealing no
> hassle easy to use reusable gasket on the market bar none.
>
> Cheers
>
> Paul
> ----- Original Message ----- 
> From: "Scott Couchman" <scottcouchman at yahoo.com>
> To: "Pantera Forum" <detomaso at realbig.com>
> Sent: Friday, February 13, 2009 9:54 AM
> Subject: [DeTomaso] Ultra Copper RTV and O2 Sensors
>
>
>>
>> I searched the archive for information about Ultra Copper RTV Silicone
>> and all the posts seemed very old. I recently purchased (OK, actually
>> my wife gave it to me for Christmas) the Innovate A/F ratio system
>> that includes bungs and O2 sensors. I removed the exhaust manifolds and
>> had bungs welded into both collectors. I'm ready to reinstall the headers
>> and plan to use gaskets and Permatex Ultra Copper RTV to seal the headers
>> to the heads. I talked with Innovate and they said to run the car to burn
>> off
>> any RTV because it will kill the sensor. Ultra Copper says it's sensor
>> safe.
>> Anyone have any experience....good or bad..... with this application? I
>> don't
>> want leaks and I don't want a dead sensor.
>>
>>
>>
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