??? How to Make Long Welds Without Expansion Cracking ???

Hello Bob,

I'm not exactly a newB to this group but I haven't watched or posted for about 8 years or so. I remember Ernie though.

On to your aluminum weld.

  1. 5052 is a MAG based high strength non heat-treatable AL alloy so your filler is correct. It starts to anneal at 650F so puddling around is not a good idea, I also would not pre-heat the structure.

  1. The 3/8" to 1/8" would require enough TIG (even pulsed TIG) energy that short cracking would be an issue making MIG or electrode the best choice. (NOTE.. I hate AL electrode but everyone should try it once.)

  2. If your 53XX wire is .035 you can successfully weld at around 120 to
140 amps traveling at 18-22 inches per minute (this will seem like it's trying to go into spray). If your using .045 wire (without pulse) it won't behave well below about 160 amps and your torch travel will be in the range of 30-40 inches per minute, (that's hard to do for anyone not used to it). I can check for the wire speeds and volts and post back.

  1. I agree with Ernie on the stitch weld with each joint divided at least

5 times and tacked about every 3 inches. Every stitch weld needs to end on a tack and fill the crater.

  1. Aluminum grows fast, but it also gives up retained heat to the air at approx 6 times the rate of iron based materials. Aluminum also responds well when the weldment is restrained as any upset of the material will occur within the weld and the HAZ.

  2. The guy a Oquaqua boats probably would just attach a strong-back to the
3/8" bar and go to town traveling at 35-40IPM (that's way better than an inch every 2 second...). But he's used to it.

  1. The torch should be angled at least 20 degrees (some go 30 to 45 degrees) in the direction of travel (push angle) and the travel speed of at least 1 inch every 3 seconds is important.

  2. On a 3/8" test piece get your volts up to reduce spatter and soot. With
035 wire I would start with 350 inches per minute wire feed and 26 volts. What you're looking for is a bead 1/4 to 5/16 wide with good appearance and fusion at the toes of the weld (no need to weave, just move).

I'll check my docs' at the shop and post back on the wire feed and volts but you've probably already finished the job by now...

Matt

Reply to
matthew maguire
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Good so far. I have a MIG rig that I have been working with.

I experienced that when trying to weld thing stuff. I had to use two hands and move the torch as fast as I could and still hold it somewhat steady.

What is HAZ?

Like clamping a piece of steel to it?

Got it. Travel very fast.

Wow. I don't my welder will do that. 350 inches per minute is screaming. I'll have to go out and look at it, but I think my wire feed speed is listed upto about 100. I'll have to look and see what the power taps are by referring to the manual.

Nope. This is a "hobby project" and I am taking my time and trying to come up with the best options.

Reply to
Bob La Londe

Reply to
emmo

The Millermatic 212 goes up to 700 IPM so 350 is only about half way up on the dial. Oh, but wait, you are using a spool gun. Hum, don't know what that will do....

Ah, the spoolmate 3035 will do 715 IPM if that is the gun you have.

My MM 180 will go up to 460 IPM and its spool gun (which I don't have) will do 625 IPM.

Reply to
Curt Welch

Upon further review...

I was about half right on the settings.

035 at 350IPM will give you about 125-135 amps, (determine wire feed by pulling trigger for 5 seconds and clipping, then measuring and multiply by 12.. 30inches X 12 = 360IPM, close is good).

My voltage was a little high (note, quit working from memory, matt) the schedule for groove welding 1/8" aluminum horizontal with 035 is -

125-150Amps, DC(EP), Arc Volts 20-24, Argon shield-30(cfh), travel speed 24-30(ipm), electrode consumed (lbs/100ft) 2.

This is from the newer Lincoln MIG/MAG guide, can't find my Miller docs but usually miller wants a little higher voltage as does thermal arc.

Try these settings with at least a 3/4" stickout to prevent burnback, and your bead profile should be convex (like a shed roof) with visible arrowheads in the surface (not like a stack of dimes).

there is some help here;

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and here;

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Miller electric has similar guides (you can spend some time on these websites just looking...).

Remember 24-30inches is near 1 inch of weld for every 2 count (I will travel the torch over a scale for a bit just to get the feel then, when I do the weld I try not to watch the arc or the puddle but rather the nozzle and the joint while feeling the speed). It is also easier to back down from hot settings if you need to rather than start too cold and try to power(and also speed)up.

You'll know when your close when the spatter (and soot) go down quickly. At 350ipm I'm not sure you can get a true spray without going over voltage (re; chemical changes in the materials!) but you should be able to get a soft sizzling arc with little spatter.

Mig-ing aluminum is sort of a brute force operation, I've seen 1/16" wire used to weld 1/4" aluminum tread plates for ladders on off-road equipment at about 300amps (thats about 3-5 seconds to weld one side of a step!). Also cover yourself as the arc will burn exposed skin FAST.

Have fun. Matt

Reply to
matthew maguire

"matthew maguire" wrote in message news:EbidnSpeauxgt0vVnZ2dnUVZ snipped-for-privacy@comcast.com...

Well, I dunno how close to your numbers I came, but I stitched it with my Miller 212. The chart on the welder says for 3/8 aluminum to run at 7 (max voltage) and 80 with .035. I found it worked a little better with the dial cranked up closer to 88 for wire speed. Don't know exactly how many inches per minute that is or how many amps, but even when I was spraying straight onto the 3/8s I was moving pretty fast. About 1 inch per second sounds right. That is what you said. (I have to move faster than that with thinner stuff)

It looks like crap even after I ground off some of the big mountains, but I don't think its going to crack. I did a little more than tack it. About every three inches I put down a one inch bead, and then I went back and filled in between. I did not preheat it. In fact I think that would have caused a major problem. I did one side yesterday. When I came back today there was a noticable seperation on the other side that was not there before I started. Since I have a lot of play in what I am doing I did my one inch tack welds right were it was rather than try and compress the entire structure to make it tight. Where I could see through the seperation I put a piece of backing in to cover the holes. Then I welded it. When I was done I ground off some older welds while I waited for that one to cool, and then I ground that one down, but not off, since I think I need the mounded bead to provide strength. I've got 2 or 3 little tiny pin holes, but otherwise it looks like it flowed into both pieces ok. I've got a touchy spot down near the bottom (changes from diagonal vertical overhead to straight overhead) of this that I want to flip the whole thing over to work on so when I have it upside down I'll put some heat and metal into my pinholes. I've circled each spot I want to look at a little closer with a magic marker so I can take a magnifying glass and look at it when I have it upside down. I probably could have done this whole thing a lot easier if I had flipped it over. I've been doing this entire repair either vertical or overhead.

This is not a repair project I would reccomend for another newbie for their first aluminum welding project. LOL. On the oher hand its ambititous enough to force me to learn a lot and really push my limits as well as the limits of my machine. On the other /other hand, if I had just done it the way the OEM had done it (light and cheap) I wouldn't have needed to push my limits quite so much either.

Notice I have quit posting pictures of my welds? That's because they look pretty shameful. LOL. Real world welds are a lot hard than practice welds when you can't clamp it all up nicely on the work bench.

Reply to
Bob La Londe

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