Sounds like not enough heat. What's your set up? I've been welding 3/8" plate. The material must be CLEAN and I preheat the hell out of it and try to keep the piece isolated from anything that will allow the aluminum to dissipate the heat. When I'm done with the connection the entire piece is roasting hot. I'm running a Miller ac/dc buzz box (225 amp) with a high frequency converter. Frankly, I should be using a bigger power source, but I'm making it work. I have an engine driven machine with enough snort but I'd cook my torch. If I had the luxury of more juice/water cooled torch, my procedure wouldn't be so antiquated. Heat, baby, heat.
Jon
By suds
Date 04-03-2010 18:04
Thanks for the feedback, I am using a Miller Dynasty 200. I guess it'll just take some more practice. Both suggestions will help, Keep Em Burnin, Suds