I got some 1/8" aluminum, and figured I'd do up just a basic box. I had some usual quirks towards the ends where you really have to get out of the heat, so that was no biggie. The main problems I had were these:

The tacks became an issue. I was tacking with a dab of filler, so when I approached the tack I ended up having a little issue. I notice with aluminum you really need to come in low to avoid the heat melting the filler, but with the tack in the way I'd have to jack my angle and I'd run into trouble.

How does everyone tack aluminum parts...just basic tacks with filler? I guess it's just something I need to work on.

My other problem was right at the end. I did a box, and right as I neared the end, all went to hell. The aluminum just got super porous and gritty looking. I thought it might be contamination, but I'm wonder if it was heat waves from inside the box making their way out as speed and basically aerating the weld pool? I assume it's just like a roll cage weld, you need at least a hole somewhere to vent weld gases inside?

Lastly, what does everyone use to clean aluminum in prep for weld? I like the wire wheel on stainless....is there some time of "wheel" I can use that cleans but doesn't give that heavy texture?

Thanks!

 

hae your freind hold it with his bare hands no me to i just got a tig (finally)

 

a light SS brush that you find in welding stores, and either lacquer thinner or acetone.
every time you stop wire brush the unwelded areas and the part you will have to pick back up on, Aluminum forms aluminum oxide pretty fast so you have to keep brushing.
It will also produce alot of soot if you dip it. I also find it best to sharpen the tungsten then take a penny and put the welder on DC+ and ball the tip up just bit, i like running a small ball on the tungsten rather then a larger one. It takes some practice.

When tacking, which is the part i suck the worst at.. i go up on amps slow untill i can get both sides of the metal to start to flow a little, then as i goto dap i ramp up the amps to try and hold off the melting of the filler untill its in the pudle. Its hard to explain on line, i just learned from welding over and over. on nice consistent good aluminum i can run nice beads with penetration, better so then with any other metal,But if you give me some ebay crap thats been polished its a bit harder, you have to really clean that stuff in and out alot.

 

To alleviate the filler issue, do more of a stabbing motion with it into the puddle....quick in and out dont hold it close to the arc

 

With tacking the pieces what I do is put just a dab on one piece, right on the edge. Then I hold it together with one hand and heat that dab up and bam instant tack that will sit low in the groove so you can just pass right over it without jacking your angle.

Its kinda tricky to do it but practice makes perfect. The first few times I did it I used too much of a dab and the parts had a gap. Its a trial and error process but it works flawless for me. Also for the porous welds at the end, its because you're too cold. I bet the puddle looks dirty. What you have to do here is move FAST. Believe me, I have trouble sometimes. Welding aluminum is like dating a bipolar chick. Sometimes shes perfect and other times its a raging bitch you want to choke.

 

bit of a thread jack but kind of on the same subject...

do they make stainless steel wire wheels that fit in a grinder or a 4-1/2 inche angle grinder. i find that sometimes the aluminum is really caked over in oxidization that just a handheld stainless brush doesn't cut it. can you use just a normal steel wire wheel if you don't use it for anything but aluminum.

 

How are you aligning the pieces before you start welding ? Are you overlapping the pieces or do you have a 90deg at the joints. I have always found that if you join the pieces without overlapping them that you can make a tack without any filler at all.
Like this


As for the problem that you have at the end of the weld near the end of your box. I have had the exact same problem and have discovered that it is actually a gas coverage issue. For me it always happens at the end of a weld when Iam welding a box or something similar. I have found that if I change the angle of the torch twards the end of the weld it usually helps a bit.

 

When i tack, i try to keep them as low profile as possible, but not too low as sometimes it'll crack when it starts to heat up...basically it takes practice.

You can also try to file down the tack.

Dont forget to walk the arc away from the tack before letting off completely.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by k24em2 &raquo;</TD></TR><TR><TD CLASS="quote">To alleviate the filler issue, do more of a stabbing motion with it into the puddle....quick in and out dont hold it close to the arc</TD></TR></TABLE>

Yeah...my stainless habits have me leaving the filler close in, under the gas shield. With aluminum it's definitely hard to break that, but once I do...yeah the quick in and out works.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by PPLH8R &raquo;</TD></TR><TR><TD CLASS="quote">How are you aligning the pieces before you start welding ? Are you overlapping the pieces or do you have a 90deg at the joints. I have always found that if you join the pieces without overlapping them that you can make a tack without any filler at all.
Like this


As for the problem that you have at the end of the weld near the end of your box. I have had the exact same problem and have discovered that it is actually a gas coverage issue. For me it always happens at the end of a weld when Iam welding a box or something similar. I have found that if I change the angle of the torch twards the end of the weld it usually helps a bit.</TD></TR></TABLE>

Yeah...I'm aligning the pieces like picture. There's a 90 degree groove opened. I had a SLIGHT gap here and there, but it does seem to want to flow together.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by robbbby &raquo;</TD></TR><TR><TD CLASS="quote">bit of a thread jack..</TD></TR></TABLE>

Yeah...your right....shhh

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by GTibunny16v &raquo;</TD></TR><TR><TD CLASS="quote">With tacking the pieces what I do is put just a dab on one piece, right on the edge. Then I hold it together with one hand and heat that dab up and bam instant tack...

Welding aluminum is like dating a bipolar chick. Sometimes shes perfect and other times its a raging bitch you want to choke. </TD></TR></TABLE>

I'm gonna try that method...sounds like a winner. And yeah, your right...parts I laid beads of perfection...then all of a sudden all hell broke loose.... Definitely reminds me of my bipolar girlfriend, so that's a very accurate depiction for you readers out there.

 

What I do for tacking is stay low on the pedal while I watch and see that the arc is jumping between both pieces of metal and they're somewhat equally up to the same temperature. When each piece has a shiny puddle area about 1 1/2-2 times the thickness of the material you're welding, then you know it's time to throw the filler in there. I usually tack with smaller filler than the thickness of the material. (with 1/8" thick aluminum, use 3/32 filler for example). You can get on the heat pretty good as long as you just shove the filler in there heavily. It should flow out nicely and not be too tall of a tack then.

For the end of your weld issue, I ran into the exact problem about 2 weeks ago. I ground down the weld multiple times, with a carbide burr bit too so as to not leave sanding disc contaminates in there, and it would constantly bugger up on me for the last 1" of total welding. After I drilled a hole for the filter tube (I was doing a catch can box), the problem disappeared, so you were right about it being similar to what you have to do with roll cages. Even after the piece cooled down, and without a hole drilled into it for venting, I ran into this problem when I tried to finish it up, so I'm pretty confident that's what your issue is too.

 

if i am working with new aluminum i just clean with acetone. sometimes scotchbrite(red) and then acetone. if its used dirty aluminum then i use a brown scotchbrite pad on my hand air grinder.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 91TSiGuy &raquo;</TD></TR><TR><TD CLASS="quote">What I do for tacking is stay low on the pedal while I watch and see that the arc is jumping between both pieces of metal and they're somewhat equally up to the same temperature. When each piece has a shiny puddle area about 1 1/2-2 times the thickness of the material you're welding, then you know it's time to throw the filler in there. I usually tack with smaller filler than the thickness of the material. (with 1/8" thick aluminum, use 3/32 filler for example). You can get on the heat pretty good as long as you just shove the filler in there heavily. It should flow out nicely and not be too tall of a tack then.

For the end of your weld issue, I ran into the exact problem about 2 weeks ago. I ground down the weld multiple times, with a carbide burr bit too so as to not leave sanding disc contaminates in there, and it would constantly bugger up on me for the last 1" of total welding. After I drilled a hole for the filter tube (I was doing a catch can box), the problem disappeared, so you were right about it being similar to what you have to do with roll cages. Even after the piece cooled down, and without a hole drilled into it for venting, I ran into this problem when I tried to finish it up, so I'm pretty confident that's what your issue is too.</TD></TR></TABLE>

Sounds good....that's also good you confirmed that vent issue. I suspected that's what it was, for whatever reason I didn't do it...who knows.

I am always going to work with the ac balance a bit. I think that there were just some areas that had more oxides and I maybe could use some additional cleaning action.

I'm gonna make another one here shortly.