bad mig welds on aluminum pipe

[dvice]

so I have a miller 250, with a spool gun.. I have welded fine with it on almost all my projects...which is mostly boat work.....090-.125 thick aluminum sheet. I have also welded some .250 plate to the back of my boat.... welding has gone fine..i was originally using 4043, but someone suggested I use 5356 because my sheet was 5052. I use .030 wire... and welding got a little harder a little less nice looking when I switched over to 5356.

SOO now I am starting to weld some aluminum pipe I bought on craigslist... I am not sure the alloy..i would GUESS 6061...its actually TUBE , not pipe. 1.187 OD x .875 IDs I tried to tach some pieces together and I got bubblegum globs.. I cranked the power up to 25!!!( I was welding the .125 sheet at 19), and kept the feed at about 4-5 and that helped JUST a LITTLE... I am getting soot and bubble gum blobs.... I am afraid to hang in there too long as Ill melt the wire back into the tip!!!.... MY gas is 100 % argon at 20 PSI..... do I need more heat??? or do I need larger dia wire??? more gas?...once in a while on this tube Ill get a shiny weld....but I was risking melting the wire to my tip!! I brought the parts I tacked to work and cleaned up the welds with the tig machine..

I have a lot to weld, so Id like to get this figured out... I am going to go buy a spool of 4043, and maybe a spool of .035 4043.....to try...

dvice

[rmacalutec]

If you're getting soot and big globs it's sounding like you're having a shielding gas issue. Check to make sure all of your hoses are not loose, and that there is gas coming out of the nozzle of your gun.

[ryanjones2150]

20 psi or 20 cfh on your shielding gas?

[OscarJr]

Depending on the size of the outlet of the MIG gun, 20 CFH might or might not be enough. I use 25 CFH if I have to use the MIG gun. Bubble gum looking blobs means you don't have enough heat going into the joint, and the weld metal is just piling up. Could be not enough voltage or wire feed. What do you mean you increase the power up to 25? Soot means issues with gas coverage or incorrect polarity. Pics of your setup? Pics of the issues?

[ryanjones2150]

I don't think 20 psi is the same as 20 cfh. Please clarify that.

I'm not a spoolgun guy, but I'd imagine it's the same as far as physics go. Increasing your wire speed will increase your amps. You have to have some wire feed speed to punch that arc in there. It seems a little backwards sometimes, but that's the way it works. I'm in the boat of improper shielding gas too.

[gnforge]

I think Ryanjones2150 is on right track need higher wire feed. If increase voltage normally increase wire feed rate. <br />
If burning back to tip increase wire feed. <br />
I never liked 5052 although sometimes needed. <br />
Id try 4043 in .035 <br />
Set voltage to 25, turn up wire speed as high as will go to prevent burn back then adjust wire feed down till get dialed in. <br />
Your wall thickness should be .312 or 5/16"<br />
If me I'd use .035 4043 if 6061. <br />
With my big 40 I'd be in the 25 V area and in the 4-5 area with wire speed if I remember correctly. So at 25 with .030 I'd guess your slow on wire feed. <br />
Hope it helps.

[xryan]

I despise 4043, but on a spool gun 5356 has always been a picky finicky little female dog... a tweak to much or too little of anything and it turns into a mess quick. I did a bunch of dock repairs using someone else's Lincoln Ranger 8 and a Spoolmatic 2. There's no way I could ever get it to run 5356, but 4043 works, just crank the Ranger to the max and go to town.

[dvice]

that's what I think I experience....I ran one spool of 5356, and it seems I had issues, where I didn't have issues when I welded similar aluminum with the 4043. When I was doing the 1/8th sheet, I was on a power setting of 19 and I was feeding 4-5...closer to 4..... and occassionaly id poke through!!!, had to keep the gun moving!!!...soo when I had issues with the thicker stuff,..i just cranked up the power.... but since I was getting globs...I didn't think MORE wire would help( I am probably wrong I am guessing now)...seemed like Id just get MORE GLOBS..... the guage is probably reading CFH...its for welding...

I still have the 5356 in the gun..Ill go home and crank up the wire feed to 5 or a little more, and increase the gas flow to 30 or 35.... and see what happens..

thanks for the feedback guys.

PS I bought some larger tips , .035 and .047 and I bought some 4043 in .035 and 5/64ths..... so I have the tools to try and throw at this issue.

[ryanjones2150]

Only change one thing at a time. I don't see any reason why 20 cfh wouldn't give you enough coverage. Too much gas can be a bad thing too.

[Olivero]

Don't want to whirlwind your shielding gas.

[FusionKing]

5356 takes WAY more wire than 4043. Like 1/2 again as much. You may just run out of wire speed capability on large thicknesses. The 350P can. (run out of wire speed) It's the mag in the wire that makes it need way more feed rate.
As far as gas flow goes, you can crank it up to like 30 or more at times before it'll weld nice on a spoolgun. You may need a bigger regulator. It's hard to get enough flow at times.
I haven't used .035 wire forever. 3/64ths just works better IMO....YMMV
Switch to 4943 and you'll be a happy camper.

[dvice]

hey guys, I did a little test last night.... threw some gobs of 5356, then cranked the wire feed up as well as the power( 6 wire feed at the spool gun, and power setting at 26!).. and it still gobbed.... then I backed the wired feed off and left the power setting high... I melted the wire back to the tip!!!!!!!!! gas flow is 25CFH...when the trigger is pulled!.......

this is feed at 6 and 26 power 5356 wire 25 cfh

so I went to the 4 wire feed and 26 power it melted back to the tip and looked like this:

after I wired brushed it.

then I switched to 4043 .030 wire... wet the power at 26 and wire feed at 5... and got a nice melt!!!




so to me the difference is the WIRE alloy!!!..... it is just difficult to mig weld with that 5356 .030 wire.... for my machine anyway... my power setting goes to 29 I think....

I should add previously I have preheated the parts with a map torch.... when using 5356...but it didn't help at all...

bob

[Olivero]

Preheat? Never done preheating on 5356, 4043 or 4349, they seem to be the easier alloys, get into cast iron and cast alloys in general, it tends to be a good idea. But then, I mainly TIG so maybe my opinion is invalid.

[ryanjones2150]

Try only changing one thing at a time. Changing the wire feed speed and the voltage at the same time is not sound process of elimination. <br />
<br />
Once you get rough starting points for different wires, record that info so you don't have to go through this every time. I also have MM250 and usually mark those points right on the dials with some chalk. <br />
<br />
That machine has a very tight sweet spot and a harsh arc, and it's different for every wire and application. As far as how that is different with a spool gun, I have no clue. I find that when I'm dialing in for a quick job, I change my wire feed speed more often that the voltage. But either way, it's generally within a tic mark or so from my mark on the dial.

[dvice]

Try only changing one thing at a time. Changing the wire feed speed and the voltage at the same time is not sound process of elimination. <br />
<br />
Once you get rough starting points for different wires, record that info so you don't have to go through this every time. I also have MM250 and usually mark those points right on the dials with some chalk. <br />
<br />
That machine has a very tight sweet spot and a harsh arc, and it's different for every wire and application. As far as how that is different with a spool gun, I have no clue. I find that when I'm dialing in for a quick job, I change my wire feed speed more often that the voltage. But either way, it's generally within a tic mark or so from my mark on the dial.

the previous owner has a white paint mark on the power settings...it is close to 19.... and he said he found 4-5 is best for wire feed..... and he was doing aluminum signs...so he was welding close to what I wanted to weld on!!!............but I think I have found out that the 5356 is a harder wire to weld with... and since I am not welding roll cages to protect my life.... I am going with 4043....they didn't have any of that newer 4943 wire where I shopped....

I still have the option of going with larger dia wire... and I may give that a try this weekend

bob