Joe what do you use to weld 304 and 321 stainless?? what rod
and what gas to get that Oh so fine bead?? it is for a set
of stainless headers for a friends 'vintage ' indy car..
Dave Dahlgren
Joe Timney wrote:
>
> Gas Shielding:
>
> This is not easy to explain...bear with me!
>
> The reason you do not want to use argon with a mig gun is called "low
> ionization or cold shutting". Argon allows that the gap between the end
> of the wire and the work be very small when the arc jumps. This causes a
> small crack at the toe of the weld. The weld will look very good but it
> can fracture. Using a 80/20, Co2 / Argon mix will cause a high ionzation
> ( a bigger gap) and allow the metal to come to temperature before the
> filler metal hits the area. Straight Co2 will typically have more
> splatter around the weld as compared to a 80/20 mix.
>
> Stick Welding:
>
> If you burn thru, which is easy welding .125 wall tubing, the metal on
> the inside of the tube is now brittle because it is not shielded by the
> flux on the rod. This CAN cause a weld fracture. This is why NHRA has
> banned the use of stick welding on all race cars.
>
> Mig Welding:
>
> Nascar uses mig welding over Tig probably because of the miles of tubing
> in one of those cars. Teams in the know, are now TIG welding the
> chassis.
>
> We all have had experience welding up cars/bikes that have held up thru
> crashes and years of abuse using mig, gas, arc and tig. Dollar for
> dollar, I spend the time to tig all tubing as from education in
> metalugy, I have concluded that it is the best welding process for thin
> tubing. I have a book from a gas supplier outlining the proper uses of
> shielding gas and am willing to try to scan some approprate pages in to
> my computor if someone would like to see them.
>
> I'm not a teacher so I hope I have explained this so everyone can
> understand it!?!
>
> joe
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