Help - Joining Aluminum 0.040 thick....

[chipz]

When I try a lap or butt tack to join 2 pieces together I end up with big lumps as tacks.
How can I make them so I can weld over them when I weld the joints. I am having to grind them off before welding.

I can not use backing strips because they are 3D shapes.

If I try low amps it takes ages and then it all seems to go at ounce.

I just want to get both edges wet and bang on the tack.

I just can not beleive you the pro's have the same problem, there has got to be an easier way.

[dsergison]

don't use so much filler. use some smaller filler to tack, just get it hot, and poke it quick with the small filler to break the surface and get the two spots together.

when you weld over it later, run forward from the bead just a hot and heat the tack a bit then go back and let the tack wick into the bead.

like I said, I'm relatively new too. but I'm doing exactly the same type of stuff and right now I don't take anything for granted.

[MikeR]

If 1/16" filler is too big, you can allways buy a small spool of aluminum MIG wire. I have some .035 5356 that works really well. Just cut off whatever lengths you like to use, put one end in your vice, and twist from the other end with a pair of safety wire pliers. Cut off both ends after straightening to get rid of any conatamination from the pliers and/or vice, and you're ready to go.

[Ed in Ga]

Mike R,
Great tip, since I thought I was one of only a few that owned a set of safety wire pliers.
Ed

[chipz]

Still struggling

I only have 1/16 so I tried flattening it. That has not worked.
This evening I have fried to tack 2 sheets together, what a mess there are ***** of weld where tiny tacks should be.

Tried triggering the torch with short bursts so as soon as it was wet I was away, but I could not get it to work. I have also got like a white rust looking reaction around each massive blob of tack.

I am heartbroken. This is not going to be easy. All I wanted was a finished product which had a nice tidy weld as the centrepiece.
Not a monsterous lump, which says p#ss poor welding here mate.

I was going to take a picture but I will not be responsible for the sudden howl of laughter which will innevitably sweep across the country as skilled welders view it and wonder how I managed that.

Back out with grinder tomorrow.

Could someone offer settings,protrusion and the like just in case I have missed something.

Thanks Lads...

[Guest]

Try this chip. Lay your 1/16" wire into the joint and use a quick short burst of maxinum current. ZAp!...now you will have to experiment on just how much current, to hit it with, but that's the way to get a small tack. When you turn down the current, you feed electrons into the base metal slowly and because aluminum dissapates the heat s rapidly, you get a rather large area that is heated up to weld temp already...hence...a lumpy tack.

[chip hayden]

what you are trying to do is tough. here's a couple of ideas you might try;
1.maybe a little tempil heat sink would keep the heat in a narrow area and not melt the whole **** thing.
2. maybe dc reverse with a 3/32 electrode.
just a shot in the dark.

[MikeR]

ChipZ, post your pictures, it'll help everyone here to make better suggestions. And I promise, noone will laugh at you. We all started the same way.

[chipz]

To MikeR and Rocky D

MikeR
I give off a deep Yorkshire laugh when I read your remark about posting pictures, I dare not take pictures of those tacks, they were EVIL I tell ya.
Sorry, I ground them off today , nearly used an whole flap wheel on them.
What about this then, I ground the tacks off so there was only the smallest bit holding them. This will enable me to run a smooth weld over them, grabbed the job which was hot, gave off the usual bast word , dropped the job and it fell apart because of those nancy tacks I had left after grinding.
I cant win. So I started again.
I know we share everything on this site but those tacks were like piles. And you wouldnt want them would you.

Anyway I am still having the same problems but the tacks are not as gruesome ( or embarassing) so when I get chance I will post some pics, as there are other issues I need to clarify.

Rocky D
Tried to lay the wire on and turn up the power as you suggested.
But as usual got it wrong, the wire curled up faster than a turtle with electrodes on its bal**. Any idea what I have got wrong here.

Thanks Lads

I will try a pincer attack on the aluminum from **** tomorrow hopefully I will catch it napping.