aluminum welding

[brian l]

I have a HH175 that I use for repairs on my semi truck. most repairs are outside and this welder has meet most every need.
Now I would like to start welding aluminum but have some questions.
First off must of the welding will be to toolboxes and floor repairs on material of 1/8 in.
My question today is about liners. Do I have to change from the liner that I am using now or will it work fine ?
Also, if I have to change liners, do i have to change each time I switch from steel to aluminum and back again ?



Thanks in advance for any info.


brian l

P.S. Thanks you Hobart for this service, your web site helped make my buying a welder easier.

[Roger]

You use teflon liner to MIG weld aluminum because less drag so less feed problems and less contamination. Teflon liners are easly damaged with sharp wire end. File off sharp end before inserting aluminum wire into teflon linner.
You use different liner just for Aluminum only because reduces contamination from liner collected flux and metal shavings. Feeding steel you can get away with oversized linner as most use same linner for .023 to .035 wire. Over sized linner causes extra drag so correct size liner should be used for aluminum.
Before Teflon liners they used steel liners for MIG welding aluminum. You still can use steel liner and experence their problems.

Aluminum wire expands more than steel when hot causing wire to bind in contact tip. A little more stick out counters that problem and longer nozzle is used recessing contact tip to maintain shielding.

Aluminum is better conductor than steel so changing stickout has little effect on weld.

Should use U groove drive roller for aluminum so soft aluminum wire isn't deformed causing feed problems.

Adjust pressure roller tension by pointing MIG gun at board and increasing tension until you get some gun rebound but wire still slips in drive rollers. This will reduce less stiff aluminum wire jamming into birds nest at wire feeder.

[deere_x475guy]

Originally posted by Roger
You use teflon liner to MIG weld aluminum because less drag so less feed problems and less contamination. Teflon liners are easly damaged with sharp wire end. File off sharp end before inserting aluminum wire into teflon linner.
You use different liner just for Aluminum only because reduces contamination from liner collected flux and metal shavings. Feeding steel you can get away with oversized linner as most use same linner for .023 to .035 wire. Over sized linner causes extra drag so correct size liner should be used for aluminum.
Before Teflon liners they used steel liners for MIG welding aluminum. You still can use steel liner and experence their problems.

Aluminum wire expands more than steel when hot causing wire to bind in contact tip. A little more stick out counters that problem and longer nozzle is used recessing contact tip to maintain shielding.

Aluminum is better conductor than steel so changing stickout has little effect on weld.

Should use U groove drive roller for aluminum so soft aluminum wire isn't deformed causing feed problems.

Adjust pressure roller tension by pointing MIG gun at board and increasing tension until you get some gun rebound but wire still slips in drive rollers. This will reduce less stiff aluminum wire jamming into birds nest at wire feeder.

Roger, it sounds like you have done this before with the 175. I would like to also do a minor amount of aluminum welding but thought I had to by the gun to do this and have a hard time justifing the $400.00 + dollars for the gun. It looks like from the advice you gave that I need the teflon liner, I think a different gas and wire and should be good to go. I have the MM175 and am not sure if the rollers are u shaped. I know they are smooth.

Thanks
Bob

[brian l]

Thanks Roger, that was just the info I was looking for. I am on my way to my local welding supply house to get that teflon liner, and to chech the rollers. I will let you know how it goes.


Thanks again, brian l

[Al T.]

Rock gave me this Miller part #194014 for the teflon liner a while ago. Its a miller liner but fits the hobart 175 just fine. Its longer though and needs to be cut. Not a problem.

I purchased another gun from Nu-Tecsys for $89 and will use it only for aluminum. I've had this stuff about 2 weeks now and haven't tried it out yet. Too many steel projects to do first.

Enjoy!

[Roger]

I don't think it worth buying spoolgun for MM175 as price is too high by time you get controller and everything. Next step up in welders that take gun without added modual is better and not much more. So go ahead and see what your welder will do. Keep torch lead straight as possable.
You will have cold starts unless use run on tab. Aluminum really needs good shielding. Run on and off tabs help.
Clipping wire flush with contact tip will help get shielding when arc starts.

Not saying HH175 is great aluminum welder just trying to reduce frustration.

About only way to use 135 welder for aluminum is with preheat.

Travel speed is high MIG welding thin aluminum thats why pulse mig is perfered. Puts weldor back in control.

[Hobart Expert Rock]

HEY YOU GUYS ARE DOING GOOD ON RECOMENDATIONS.....ONE MORE THING TO THROW IN IS DON'T FORGET THAT ALUMINUM COOLS REAL FAST AND MAY CRACK AS WELL IT ABSORBS ALL YOUR HEAT AND MAY CAUSE CRACKING ALSO........NOT TO MENTION IT WILL WARP.........JUST SOMETHING YOUR GOING TO LEARN WITH EXPERIENCE..........YOU SHOULD SEE THE ALUMINUM DUMP BED WE JUST WELDED A STEEL LINER IN.........WHAT A PAIN..................ONLY DOING 6 TO 10 INCH WELDS AT A TIME...... VERY HARD TO DO A PREHEAT IN THE COLD WHEN IT IS 28 DEGREES OUT..............GOOD LUCK....................ROCK[email protected]

[brian l]

Hi guys me again, Just spent a day learning to weld aluminum and let me teel you what an experience. At first it was one problem after another, much trial and error. I'm getting the hang of it but I keep having the same reoccuring problem.
I can get a nice bead going then no more arc and the tip is melted.Time for new tip and try again. What am I doing wrong ???
I try to mantain about an 1/2 in stickout and I am welding 1/8 in material with a HH175 set on tap# 3 and wire speed of 90.

Thanks for the help
brian l

[Roger]

Increase wire speed or reduce voltage to prevent burnback.

[brian l]

Thanks Roger I will give that a try. I'll let you know next week I go back to work today. Thanks again for all your help.

brian l

[brianw]

running along fine and then having the wire burnback is pretty typical when trying to run alum through a regular mig gun. Welding along then move the gun a little too much and the wire hangs. you have to really concentrate on keeping the gun straight. also do not get frustrated and start cranking down on the drive rolls, you want the rolls to slip if the wire gets stuck, else it is a lot bigger mess to clean up (usually involves disconnecting the gun from the machine). Good luck and keep your happy place in mind ( you know, the place where you own a spoolgun).