[jmcglash]

Starting with the filler 4043 is easy to weld with compared to 5056 but 5056 feeds better in a mig setup.

Argon gas is a must

CLEAN metal is a must. NO sand paper (aluminum oxide is evil). Scrub
with a stainless steel wire brush.
AlumiClean - Aluminum Cleaner & Brightener will strip all oxides better than a wire brush.

8020 and the like is Anodized Aluminum and the anodized layer must be
removed first. Dollar store oven cleaner is lye (Sodium Hydroxide) is a
spray can and will remove the anodized layer in about a minute.

4 part each weld, looking at the clock face 1-3 6-9 3-6 9-12 and skip
around the piece. this will keep the heat down. Even so clan the part
well.

The advice to practice on some scrap is very good advice.

Good luck and have fun with it.

Jim