[chadwarden]

I don't know why this is such a big problem for me. I was able to do flat butt welds fine but my fillets are inconsistent, white or just down right ugly. If the plate is 3mm, what range should my amps be? Is 120hz with 65% ac balance a good setting for this particular weld? Aluminum turns white when too hot, right? I think my biggest problem may be heat input (I'm using a pedal). Any tips and tricks will be appreciated.

[Otto Nobedder]

The trouble with aluminum fillets is the tendency for the arc to want to go to one plate or the other, not down the middle like you'd want it. 120 Hz and 65% are fine. For 3mm, with a pedal, I'd have my peak set around 200A, for ease of establishing the initial puddle, though as the weld progresses, I'd likely be using 100-120A, or just over half-pedal.

Consistency in a fillet relies on two things... Not advancing to far with each move, and not feeding rod too soon. You want to move the arc to the front 1/3 of the puddle, and wait to see the puddle advance to meet you before you feed filler.

As far as a white surface on the weld, I suspect, if you watch, you'll find you're using a sharper torch angle in the fillet, to aid seeing what you're doing. This gives you less trailing gas, allowing the weld surface to oxidize more and faster.

Without watching you weld, this is all speculation based on your description and mistakes I've made. If any of this seems to apply, I'd suggest focusing on the consitency first, and torch angle later. My reasoning is, if the wire wheel cleans the metal to "shiney", no harm has been done to the weld, strength-wise, by the white finish, and it's a lower priority "problem". It's also hard to focus on two or more issues at once.

Steve S

[chadwarden]

Thank you for the good advice. I'll make these adjustments and see what happens. Btw, would it be "bad" to sharpen the tungsten to a needle point? My book and my teacher told me to just have a slight taper with a flat end. I find that this makes for a too large of ball that becomes really big on one side, making it really hard to focus the arc on where I want it to.

[Braehill]

chadwarden,

If you are using pure tungsten I would have to agree with your teacher. I weld Aluminum with thoriated tungsten and sharpen it to a point. That being said, I usually let the tungsten decide how sharp, meaning if the end doesn't split at whatever amps I'm welding I sharpen to a needle. If it does I'll flatten it a little. If it still splits, I go to the next size larger until it will carry the amps. There's a million arguments about this and that's just mine.

I use a transformer welder without squarewave and I've heard it said that you have to use pure with this type of welder on Aluminum. I've welded with it since the early eighties and maybe less than a handfull of times have I used pure to weld anything.There was no such thing as a welding forum and I didn't have anybody to tell me what you can't do. Not knowing any better I just welded with whatever I had, that was free thoriated that I found in a steel mill that I helped tear down.

My point is experiment with your equipment and consumables and watch what it does. It will teach you alot. I used to keep a notebook on my welder and wrote down what worked and what didn't. Come to think of it there was alot more pages of what didn't than what did, but I learned and so will you.

Len

[Otto Nobedder]

I'll weld with pure or thoriated (or ceriated, etc.), whatever's available.

On pure tungsten (as your description suggests you're using), no. Dont point it. It's going to ball anyway. I'll just round the end over, and let it take care of itself.

If the ball does not stay in the center, the tungsten is getting too hot, and you have three options to improve it. Set the balance farther negative, reduce your welding current, or go to the next larger tungsten. I'd try the first two before going larger on the tungsten... With the balance set farther negative, less overall current is required for the weld. You'll get a narrower "cleaned" zone, but as long as it stays as wide or wider then your bead, you're golden. The effect of setting the arc balance higher (more negative) is less of the heat is flowing toward the tungsten (which causes the balling in the first place) and more into the metal being welded. Try going to 80%, and using 10-15 fewer amps, and see if that improves things any.

Len is quite right, though. Alloyed tungsten will work also. They are trickier for critical welds (that will be x-rayed), because they will splinter and spit as he described when not dialed in right, and leave inclusions in the weld, but I do it often on a synchrowave 250. I only break out the pure for pipe and vessel welds, and only the vessel welds are x-rayed.

Steve S

[chadwarden]

My teacher said zirconiated is better than ceriated for aluminum welding (the one I'm using). Any truth to this? Btw, my machine can only go up to 65 ac balance.