I would like to know if welding aluminum is possible with a Millermatic 251, without a spool gun. That is, would the regular wirefeed be able to push aluminum wire through a regular MIG gun like Bernard Q-30 series. If so, what would be the typical grades of aluminum wire used and can I use 25/75 mix for that.
Possible? Yes. Bitchy? Even more so. The only wire you'll push through that whip is the 5000 series. 4000 series is too soft to push. 5000 series is _very_ smoky and messy. You use straight Argon, and maybe a bit of Helium in the right circumstance. Would I do it? NFW! TIG rules, especially in repair work. YMMV phil
5356 wire, a teflon liner for the gun, pure argon or argon/helium mix. You have to keep the gun cable very straight, and clip off the wire flush with tip every time. For 3/64" wire use a 1/16" tip. Smooth drive rollers are best so you don't indent teeth into the wire, therefore increasing friction. Drive roller tension should be set so if the wire is stubbed out it slips on the drive rollers. This reduces the chance of bird-nesting.
One of the main problems is the slight delay in the gas flow. This will make a slight barf at the beginning of each weld, unless you hardwire an over-ride for the gas solenoid in the machine so you get pre-flow gas.
How common are rollers with teeth as I've only seen one, although I've only looked at a few dozen MIG wire feed rollers over 25 years. The particularly one was on a small low end MIG and was a PITA, as while I could adjust it to work OK and not birdnest at the slightest sign of the wire sticking, the owner couldn't. In the end just machined as much of the tops of the teeth out of the grooves to reduce the bite and job done, everyone happy.
Ah...er....ahum......you dont? Really? Your kidding everyone...right?
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