LAC welders

Fri Apr 23 18:50:38 EDT 2004

For a first time welder, I would suggest a GMAW with inert gas. My personal 
welding stable includes a 220 VAC Miller 250. I use a 75/25 Argon/CO2 mix. If 
you want to weld stainless steel, you need to use a tri-mix of Argon/CO2/ 
Helium. I have seen gasless/flux cored MIG welds and they look awful. Penetration 
was lacking and that leads to poor strength at the weld point. Inert gas helps 
penetration and also shields the weld from contaminates.

Another type of gas to use for just about everything is called Startgon or 
Mastermix depending on your gas supplier. I have used this gas and the weld 
quality is excellent.

GMAW is also one of the easiest welds to perform. After you get a MIG 
machine, go to your local sheet metal shop and ask for some scrap metal to practice 
with. Get all different gauge metal and start with steel first.

Aluminum welding is performed with a GMAW machine with a spool gun. The 
aluminum wire is not strong enough to be pushed through a long run of the normal 
MIG cable lead. So a gun is used that keeps the aluminum wire travel distance to 
a minimum. Wire speed is increased and a typical example would be between 
425-450 ipm (inches per minute) for 3/16" aluminum and running 140/150 amps and 
using .035 wire. Compare that to welding 18 gauge steel using .035 wire. The 
wire speed would be around 180-210 ipm at 90/110 amps. Pretty big difference.


Jim Furdyn (FAA certified aircraft welder)
Cherry Hill, NJ

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