Techniques for welding thicker, cast and magnesium aluminum
- see "Cast Aluminum".
Start your practice on thin aluminum tubing. Poke as many holes as possible
in an 18" length of tubing. Repair half with propane, half with oxyacetylene.
When using oxyacetylene with Super Alloy #5, wear dark glasses.
When using oxyacetylene for thin aluminum repair or fabrication, use a small tip
("0" or "1") with a 3/4" carburizing flame. Pull blue flame out about 3/4"
with very little oxygen (hissing).
On larger thin aluminum parts such as an auto hood or a boat, always use oxyacetylene. This enable you to get the local area up to flow temperature more quickly - before the heat can travel to outer edges. Just
turn oxygen up a little at a time
until the rod flows. Practice on a similar disposable part first.
If the tip of the rod balls up upon touching the aluminum, it means more heat is
Ø When doing lengthy fabrication, liquify 2 to 3 inches of flux
at a time, and flow in the
Continue this process to completion.
If the flux is liquid and you are about to begin laying in the rod, but the phone
rings and you are called away - reactivate the flux by heating it upon your return.
When welding thin aluminum next to thicker aluminum, the thicker part will steal
most of the heat, so heat the thicker part first, until a little flux liquifies
on it. Then, when you go after the thinner part, there will be no heat transfer.
Because heat disapates so quickly through aluminum, move without hesitation from
one step to the next - melt the flux off the rod...heat until the flux liquifies...come
back in with the rod...come back in with heat...