Aluminum Welding questions?

[droptopgt]

Hey guys, i looked in the search feature but can't get answers to the following questions. I have a MM 210 and have just bought a 3035 spoolgun to do aluminum. Most of the welding i do will be 1/8" square tubing to build a couple trailers and a headache rack for my truck. It will mostly be 2x2 or 1.5 x 1.5 tubing for the trailers racks. Now for the questions..
1) Does the metal need to be preheated? If so how - with a propane torch or something?
2) Do i use 4043 or 5356 aluminum. Whats the real differences with the two. Can i mix and match the two. If i have a spool of 5356, can it be used on a piece of 4043?
3) What does push/pull mean. I read alot about it but cant find out what it means. Is the push/pull gun the spoolgun?
4) And finally when welding aluminum, do i go from left to right, or right to left? Do i keep the arc in the puddle or away from it, thanks.

[aametalmaster]

1/8" really dosen't need a preheat but a propane torch works great.

4043 is usually what is found on a suppliers shelf.

Push pull is the gun because it has a motor to pull the wire thru. Instead of pushing from the welders drive and up the mig cable.

I go from right to left because i can see the puddle better. Keep the gun at a slight angle just back off of 90 degrees like 80 or so and push the wire into the puddle.

I don't weld that much 5356 and if i do i don't know it and use 4043 on it because thats all i use....Bob

[welder_one]

alright, with a push pull set up, the feeder and the gun has a separate set of drives. the gun drive is actually the control and the drive in the feeder is the slave. the xr-a and the xr-edge is an example of push-pull...

on 1/8 material, preheat is absolutely not necessary. i dont even preheat on 3/4 inch but the mm210 is not heavy enough for that... you will probably run about 190 amps for 1/8 and be sure to have your running shoes on...you'll need to move quickly...

the biggest difference that i have found between 4043 and 5356 is that the 4043 is a little more fluid of a puddle, the 5356 is easier to feed with less "bird hotels" if you are going to post heat treat your welds, then you must use 4043 alloy. if you are going to anodize then you must use 5356. on a non post heat treated weld, the 5356 is actually a stronger weld...i have never tried to mix the alloys and i am not sure that i would recommend it at all. if your parent metal is 6061, either will do nicely.

when welding aluminum, it does not matter the direction of travel except vertical down. lead into the weld with about 3/8 stick-out and a push angle of about 5 to 7 degrees. do not use any torch manipulation, only a straight stringer bead. when done properly, your weld will have a v-shaped bead raised slightly in the center and be fairly shiny.

as always, turn it up and burn it in... if you think that you might be hot enough, turn it up a little more and move faster...lol


hope that i could help a little, if you have any more questions, just ask...

[c wagner]

Great advice from both guys. 4043 will be easier to make a nice looking weld with. Practice, practice, practice and have fun with it... oh yeah I'll remind you one more time, push on aluminum don't drag/pull.

[droptopgt]

so i did my first welds on aluminum on a bunch of new scrap pieces i got from the local metal depot. I had the welder set at 4 and 70, miller 210, and the argon gas at 35 cf. It looks not bad, except around the welds the aluminum is like covered in a layer of brown and black soot. I can't find on this forum what is causing this. I can take a picture if i need to. Help!

[Clavacle]

You can take your gas pressure down to around 15 or 20 cfh. You will always have some black soot around your welds most of the time. There will be even more if you switch to 5356. It's just part of the process.

[dabar39]

With the questions you are asking you are nowhere ready to start building trailers and sending them out on our highways. I'm surprised no one else has mentioned this yet. It seems pretty clear to me that you have not done any work with aluminum and putting something out on the street with millions of other people is just looking for trouble in my opinion.

Get your self some practice with something other than structural or vehicular type projects. I'm not trying to be rude or put you down, just thinking of the safety of the general public. Too many things are cruising down the highways that are poorly constructed, poorly welded, or just plain out unsafe. Just wait a while and gain some experience before you take on the task of building something that could possibly put yourself or others in harms way. Dave

[Clavacle]

I would have to agree with DaBar. I have been welding aluminum for about 2 1/2 years and I am still very cautious when doing it. I have faith in my self that I am doing everything the right way and taking the necessary steps to check myself but I would still be a little apprehensive to weld anything that would be getting pulled down a freeway.

[aametalmaster]

You have smut. Here are a few tips to get rid of it....Bob
http://www.thefabricator.com/Aluminu...cle.cfm?ID=554

[FusionKing]

I also agree that trailers and such is NOT the place to learn to weld aluminum.
I weld aluminum in my own biz for several years now and I can assure you that aluminum is a poor material to make trailers with unless it is an engineered design. Even then it still has a limited life span.
If you look at GOOD aluminum boat trailers you will see they are bolted and never welded. Welding removes the temper and it is very expensive to get it back.