I have a crack in my RS2000 alloy sump....... 'Bummer!'
Has any one got any experience or advice with welding aluminium using a MIG welder with argon-shield gas?
Cheers in advance.
The Baron
Mig welding aluminium is not advisable imho. The only times I have been deperate enough to give it a go i ended up blowing holes through the ali, even
on low low power.
Cast ali sumps do not get on very well with MIG welders.
Its possible, but most Migs that are capable of welding ali are job specific or are programmed to do both, your typical semi pro or hobby Mig dont usually work well, good quality pro gear has for instance a torch that pulls the wire rather than the more common push rollers. The ali wire is a lot softer and tends to scrunch in the liner/torch. Check out local welders with a pulse Tig, wont cost much if u haggle
I have welded sheet alloy with my MIG, and made a fair job, (after a good amount of practice). I think that when you weld cast though its a different ball game. Mind you what 007 said makes more sence, get somebody to TIG it. atb Chippy
I have used the 'Lumiweld' sort of stuff for fixing holes in bike casings. I've managed a leak proof mend but it wasn't pretty!
You clean the area and then soot it with a sooty acelylene flame. Then heat it with the oxy/acetylene untill the soot burns off, then scratch the
Lumiweld stick into the joint.
If I had the choice, I'd take it to see a TIG man.
[Edited on 14/6/06 by owelly]
Best option I imagine for a crack, alternative to a tig repair, would be the low temparature aluminium "solder" stuff that there always
seems to be a demo of at every show, Lumiweld? or similar.
At the Stoneleigh show the guy was soldering coke cans to monkey metal to ally sheet, looked like a piece of cake to do. I imagine soldering up a
crack would be a simple case of sawing out a gap and filling it. However, the stuff wasn't cheap 
A friend of mine welded both mine and his shortened sumps with a 3 phase mig, it pushed 0.8mm wire and with a few setup problems, did the job,
however, it needed a lot of amps and pretty it aint!
Plenty amps, fast wire feed and argon gas. A slightly oversize tip helps and teflon liner. Glue it up with some JBWeld and save yourself the hassle.
Stay away from Looniweld, DAMHIK.
Get it proffesionally welded
Hi, the good news is that your sump can be repaired. A TIG welder will have no trouble in welding cast aluminium. It should not cost a fortune and it
will save you the price of a new sump.
Best of luck
Cheers
John
Just mig it .Its not THAT difficult!!
http://www.locostbuilders.co.uk/viewthread.php?tid=46627
I concur, not difficult at all, just keep looking at the edges of the weld pool, if the sharp edge disappears, trigger off for a split second and carry on. You get plenty of warning of a blow through.