Howdy folks, looking for advice here. Thought I was an old pro when it comes to mig, but was recently given the task of welding the spars and wing skins to re-assemble my new toy at the Dumfries and Galloway Aviation museum, an ex Saudi air force F53 EE Lightning jet fighter. The wings were cut off to get it on the loader to move it to Dumfries. I've done tons of steel, but today was just reminded that aluminium is a different matter, as I ended up with about 60 feet of spoilt birds nest of ali wire on the garage floor, lots of expletives etc. I'd forgotten I'd tried aluminium a few years back. The scenario is me and my trusty old 100emk2, argon and really thick aluminium spar inserts which slot into both halves of the aircraft wings to bolt it all back together. The skins would then be welded and flushed off after. Had a look at this site, and didn't realise about oxidisation etc, and obviously have a lot to learn about wire feed speed and current settings etc. I have used an oversize tip, and whacked it up fast feed and highest setting, as I thought the 50mm thick lump would require it. This resulted in a spark at the tip, then the wire buckling up at the rollers as shown elsewhere on the site. I'd appreciate any advice here on settings, speeds, techniques etc, on welding the large spar inserts, and also on wing skins when I actually get the wings bolted back on. The skins are pretty thick, about 5 - 6 mm, and I'd probably only be able to fill the cuts on the top due to gravity. Hope to hear some good advice from supportive guys who wont be sniggering at my optimism here! Cheers, Brian M