Pre-heat your part. Alumiweld won't adhere well if the part isn't up to temp, and aluminum wicks the heat away so fast you'll have issues. I pre-heat the parts in the oven.

Here's a thread I posted about Alumiweld back in '08 over on SOCH4.net:

http://forums.sohc4.net/index.php?topic=36600.0

myst1c

"Know the smallest things and the biggest things, the shallowest things and the deepest things."
- Miyamoto Musashi