Learning Aluminium

[gimpyrobb]

So I've had a couple of push/pull mig units for a while. Now that I have an Al flat bed on my pickup, I'd like to add stake pockets and a rub rail to the sides. Of course, that comes after I weld on the rear C channel cause I shortened the bed a tad. Here is a couple pics of my first Al welds, I know - no big deal, but its exciting learning a new process! If anyone has any old Cobramatic stuff laying around, I'd be interested in it!

 

[gimpyrobb]

Toward the end, I got some satisfactory bead profiles and penetration(last pic). I was wondering, anyone know what causes that sugaring(evident in the 2nd pic)? I thought it was lack of shielding gas, but from tinkering around today, that didn't seem the case.


ALSO! No matter how excited you are to try out new toys, don't forget to put pants on! My legs are not happy I wore shorts today(arcburn!).

 

[pjwest03]

Sugaring is usually a "Stainless" welding problem from oxygen getting into the arc area, or on the back side of the weld. With aluminum it's all about cleanliness. De-grease the metal and clean with a stainless brush. Keep your aluminum tools separate from those used on other metals. Other than that, you might need a different alloy wire depending on the base metal. Also, when MIG welding aluminum, it's better to push the weld than pull. As the work heats up you will need to increase the travel speed a bit as aluminum has great thermal conductivity.

Aluminum puts out a huge amount of UV light compared to working with mild steel. You really can't have any exposed skin that you want to keep. Even your denim jeans won't be good enough if you go for a long session. Production welders will tend to wear full leathers and hoods no matter how hot it is.

 

[Lonnie]

As stated above, that is typically caused by the oxidation on the metal.

The best method is to remove all oils from the metal with good cleaner, then aggressively clean the aluminum with a (new) stainless brush.

The dull grey finish on aluminum is aluminum oxide.
It melts at a significantly higher temperature than the aluminum & you can actually see it form a skin/barrier over the molten aluminum when the material is not clean, or it splatters leaving the rough sandy texture you show in some of the pictures.
When clean, the aluminum should flow & look almost like solder with minimum splatter.

 

[MWMULES]

What they said! I can stick two pieces of metal together but I am not a welder. I have a friend who can run a bead on a beer can, he is a welder!

 

[profo]

It also looks like your running your wirespeed to fast or and you may have your welding voltage to high, what alloy are your using 5356 or 4042 cause high grade alluminum you need to use 5356 minimum.
100 percent pure argon shielding gas. approx 20 cfm
And if your think its clean , clean it again, that is the #1 problem all the time.

 

[gimpyrobb]

Yes, I have read all those tips. Just to see what the mig boxes would do, I used some old crusty Aluminum I beams. I sanded, then wire brushed, then wiped with acetone. From some of the reading/searching, it seems like I might try a little more shielding gas. I was using about 15-20cfm and I've seen some say as much as 40-50. This was done outside and there was wind during some of the welds.

 

[gimpyrobb]

Profo, that is one of the big issues I have, I'm using an older Powcon welder that doesn't have specific voltage or amperage settings. In addition, the push/pull boxes don't have IPM indicators. I'm not as worried about the pretty welds, just as long as they are structurally sound.


Edit, one spool is 5356 3/64 in the mk3a, but the other has no labels on it. It is smaller though.

 

[profo]

Yes, I have read all those tips. Just to see what the mig boxes would do, I used some old crusty Aluminum I beams. I sanded, then wire brushed, then wiped with acetone. From some of the reading/searching, it seems like I might try a little more shielding gas. I was using about 15-20cfm and I've seen some say as much as 40-50. This was done outside and there was wind during some of the welds.

Just the slightest winds will give you splatter you may have to weld with the wind (going the same way as the wind by leaning gun in the direction of wind and turn up gas to about 40 cfm).

 

[profo]

Profo, that is one of the big issues I have, I'm using an older Powcon welder that doesn't have specific voltage or amperage settings. In addition, the push/pull boxes don't have IPM indicators. I'm not as worried about the pretty welds, just as long as they are structurally sound.


Edit, one spool is 5356 3/64 in the mk3a, but the other has no labels on it. It is smaller though.

3/64 is very large wire that should be used on 1/4" or better plate you would do alot better with some .035 or .030.

With the 035 you can turn up voltage so you have good penetration and start slowing wire speed till you get the drunK bee sound.

 

[gimpyrobb]

Well, the I beam is close to 1/4 inch at the ends and thicker near the web. The Cobramatic with the thinner wire didn't lay as nice of a bead imho. Still tinkering and learning, thanks for the input!

 

[pjwest03]

For any gas shielded welding process outdoors, you should rig up a windbreak of some sort around the work area. Even slight breezes can and will blow the gas away.

 

[gimpyrobb]

I understand and have had to do that in the past(on steel projects). This was just a down and dirty test to see if the wire feeders would even work.

 

[Recovry4x4]

AAluminium was an easy process for me to master. Drag parts to Devilman96, tell him where to stick parts, load same into truck. With that said, now that I am retired I'm going to take a class on class at the local tech school. Never did learn. Did buy a new Millermatic 211 before selling my job.

 

[richingalveston]

good info here, I have a 110 Lincoln wire feed, I put a Teflon liner in and have become an ok aluminum welder. Mine can only use the .030 wire since it has the liner. One of these days I will get one with a spool gun. My biggest problem was getting the wire speed set to keep a good bead. Always tried to go to fast.

couple of questions. I have welded a lot of scrap stuff so I do not know the grade of the metal, any clues on how to test it?

gas is another question. I was sold the rig by a guy who gave me an argon bottle because that is what he was using, the welding shop steered me to a mix gas. It seamed to work better, Is that because I was using low grade aluminum?

I am an beginner with aluminum and only a hobbyist and farm welder for steel I also have a Lincoln ranger 6 gas powered weleder. I got my first welding sun burn when I was 12. Wearing shorts while sitting on a stool welding stuff between your legs is a bad idea.

subscribing just to learn more for those in the know.

Thanks
Rich

 

[gimpyrobb]

You should use 100% argon unless the Al is real thick, then you can add helium to it to help heat transfer.

Edit, sorry for the delay, I had a knock at the door. Do you know the specs on your welder? Amp output and duty cycle? Miller has a handy phone app for weld settings, might help a bit.

 

[74M35A2]

For a first time, good job. I like the 3 on right of the vertical 2nd pic. You are not welding a nuclear reactor chamber.

 

[just me]

I have never tried MIG welding aluminum. I TIG weld it often. Slower, but great control. ANY breeze will blow the gas away and cause issues. Always set up a windbreak. And as with ANY welding process, the only way to get good is to practice.

 

[gimpyrobb]

Yup, I have 2 tig units to start using too, just haven't gotten to them yet.

 

[swbradley1]

You are not welding a nuclear reactor chamber.

Are you sure about that?