When Smitty welds heads first we bead blast them to remove any
contamination. Then we bake them in an oven to 500 degrees for about an
hour..Smitty then puts them in a special open top brick oven that is heated
by a coleman stove and then heliarcs any cracks, damaged areas or areas to
be be built up. Then he has them machined and surfaced to replace seats,
guides etc. finally he has a special router and guide that recuts the oval
water passages to correct dimensions...The finished products are very much
like new....Heliarc is the only way to go!
-----Original Message-----
From: Ron Tebo <tebomr(at)cadvision.com>
To: RobCarpent(at)aol.com <RobCarpent(at)aol.com>
Cc: alpines(at)autox.team.net <alpines(at)autox.team.net>
Date: Tuesday, March 16, 1999 8:39 AM
Subject: Welding Processes
>
>
>RobCarpent(at)aol.com wrote:
>
>> In a message dated 3/15/99 5:26:37 AM Pacific Standard Time,
>> tebomr(at)cadvision.com writes:
>>
>> << Porosity is also often a problem with aluminum welding, especially if
it
>> was done with mig rather than tig welding. >>
>>
>> What is "mig" and "tig" ?
>>
>> Rob Carpenter
>
>Rob:
>
>These terms are weldors jargon, and MIG stands for "Metallic Inert Gas"
welding
>and involves using a machine which feeds
>continuous filler wire into the weld area where the arc is shielded by an
inert
>gas mixture (also more recently known as GMAW).
>
>TIG stands for "Tungsten Inert Gas" welding (also GTAW), and involves using
an
>air or water cooled non-consumable tungsten electrode which provides the
>welding heat and is shielded by an inert gas mixture, while filler rod is
fed
>in by the operator.
>
>The term "heli-arc" isn't really specific enough to be useful to a weldor
since
>all it refers to is the presence of helium in the shielding gas in either
>process (helium is used in welding copper, nickel-alloy and other reactive
>metals, as well as aluminum and is also mixed with CO2 and argon for
>high-strength steel).
>
>The TIG process will usually produce a superior weld on aluminum in the
hands
>of a skilled operator, while the MIG process is faster, cheaper and
requires
>less skill (also much cheaper machine). For welding a cylnder head, the TIG
>process would be the way to go because of better heat control (the arc can
be
>controlled in mid-weld by a foot-pedal) and more precise welding ( it
happens
>more slowly and voids and porosity are easier to detect).
>
>Hope this helps -ask if it doesn't!
>
>Ron Tebo
>
>
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