[TheForge] Aluminum welding

[Peter Fels & Phoebe Palmer]

In conventional heavy duty frame welding, the assumption is that because 
the weld interrupts the heat treating and violates the grain structure, 
that the weld will be weaker than the original beam. For that reason , 
frame welds are generally " Fish-plated"  on both sides with plates that 
overlap and span the weld considerably. The fish plates are never welded 
perpendicular to the beam...only parallel.
You have a situation where the original beam wasn't strong enough to 
begin with....so reinforcement with a heavy hand is called for.
Personally, i refuse to know anything about aluminum...pasty stuff tat 
it is~..pf

John Allen wrote:
> I welded an aluminum dump truck dump body frame rail together since a
> 4 foot section had to be replaced at the pivot end. I replaced the 6
> inch I beam with a new one and I welded it together. The owner has
> contacted me that the weld broke. I fixed it and gave it back. He now
> said it did it again. It is breaking from the top of the beam down.
> 
> I made straight cuts and there was about a 3/8 inch between the old
> one and the new piece. I mig welded the outside after I cleaned the
> joint with a brand new stainless steel wire wheel and then aluminum
> cleaner, muradic acid. I welded it at proper settings and helium gas.
> I even cross stitched weld over the vertical weld to improve strength.
> I am using 4043 3/64 wire
> 
> After it broke the first time, I asked other welders what I did wrong,
> they don't know. I am loosing my mind trying to figure it what I am
> doing wrong. I do not have a welder heavy enough to put out 250 amps
> to tig weld it but I do have a 302 trailblazer that I could run 225
> amps to tig it. I don't know what to do besides replacing the entire
> beam and eliminate the weld.
>