Want-A-Be welder

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I have had a Hobart MIG welder for years ... Handler 135/175 with a H-10 gun.  I use the welder for "household/garage" type welding ... nothing safety related because I'm not that good. I have always used flux-cored wire, have never used any type gas. I want to try and weld aluminum tubing (wall thickness 1/16") using .030 solid aluminum wire. Can I use a "copper" contact tip in the gun or do I need an "aluminum" contact tip with the aluminum wire? Do I have to use gas? If so, can I use C25 instead of 100% Argon? I would like to only have one bottle of "super" gas that works on everything. What did I not ask??
Reply:Hello and welcome. You are listing 2 different machines. The HH135 that tops out at around 135 amps and is powered by 110v household power, or the HH175 that is a 175 amp machine powered by 230v power. It will make a huge difference whether you can do alum successfully or not based on which unit you have.Alum is a great heat sink, and as such needs lots of power to weld compared to steel. While they say the HH135 will do alum, it's really way underpowered to do so.  Mig alum is a "hot" process, however the HH135 really only has the power to do maybe 1/16" aum. You will have a very narrow range to work in. To hot and you will blow holes in your alum, Too cold and you will not get good fusion into the base material. You are walking a knife edge with this machine.The HH175 maxed out will barely do 1/8" alum. Duty cycle will be extremely low, and you really need more amps so you have more room to make adjustments. You have the same issues with 1/16" alum as far as being on the knife edge between being too hot or too cold.Alum wire is very soft and jams really easily. To run alum thru a standard gun you need a teflon liner and have to keep the gun dead straight. Most people have poor results using this as the long gun builds up friction and causes the wire to birdsnest very easily. Some have cut the gun length way back and had semi reasonable results, but many still fail even with this modification. A spoolgun is really the easiest way to run alum mig off a small machine. The downsides of trying to weld alum with the HH135 doesn't really justify the cost of a spoolgun.Alum wire expands when hot, so many times guys go up one size in tip size to help combat this, they also may cut away part of the tip to reduce friction and make it easier to deal with the wire melted to the tips. 100% argon is required. There is no magic gas that lets you do everything with only one gas. Some will simply take there C25 cylinder in and exchange it for 100% argon for that project. Down side is you loose any gas in the cylinder when exchanging, so it's not often the most cost effective way to do this.Alum mig also is not like welding steel. You have to push the bead and move probably 3-4 times faster as well as have your settings pretty much maxed on wire and voltage, say if you are doing 1/8" with the HH175..No government ever voluntarily reduces itself in size. Government programs, once launched, never disappear. Actually, a government bureau is the nearest thing to eternal life we'll ever see on this earth! Ronald Reagan
Reply:My welder is a 135. The title on the operation manual say 135/175 because it covers both ... just figured that out after you pointed it out.  You must have been looking "over-my-shoulder" because I have had every problem you mentioned trying to use aluminum wire. I may get some argon gas and play around to see if I can do anything with aluminum. Thanks for the quick response and sharing your knowledge. Regards.
Reply:Welcome to the forum.Lincoln A/C 225Everlast P/A 200