[CaptainDave75]

Hi guys , CAPT. Dave 75 new member Appreciate any help.i have a miller 180 SD syncrowave. Trying to weld 1/4" 6061, seems not getting enough heat to puddle up and weld with amperage at 180. ? is 180 amps enough. Using 3/32 2% tungsten -#8cup-18-20cph.

[CaptainDave75]

Mistake. In last post I use pure tungsten not 2% Sorry

[tweake]

just looking at the miller chart, it says you need around 300 amps for 1/4". just a tad short i think.

[cj737]

You don’t need 300 amps. You DO NEED to preheat that material because 180 amps can weld it, but it will take all you’ve got to get it to puddle.

Crank the Hz as high as it will go, set your Balance to 72-75, and heat the material with propane, MAPP, or Oxy/Ac. Then give it a good whack with the full Monty of amps.

Of course if you CAN, getting a bottle of Argon/Helium mixed in will help a great deal. 10-25% Helium can make all the difference on thick aluminum.

[BillE.Dee]

As cj stated, you will need everything your machine can give you. Typically you would need one amp per thousandth thickness of the material Plus 20% and control the heat with the pedal. Don't be afraid to get right after it. You don't really want to hang around waiting for a puddle to form. Preheat will help you a lot as will helium mix IF you can find/afford it. All the best and keep us posted.

[tweake]

i'm not up on those machines but it looks like its transformer machine. probably no freq adjustment, no balance adjustment.
if you want to try it, i would pre heat, low balance (if you have it), a 5 or 6 cup, 1/8" pure tungsten. helium maybe as its $$$$.
it also depends on if you just want a puddle or full penetration.
if its the model with no balance control then i highly doubt it will work well.

[CaptainDave75]

Thanks guys for all your help that's a huge I definitely believe I got to get more amperage and like you said I have preheated it with 1/8-in tungsten I have no high frequency adjustment or balance on that machine.

[taiwanluthiers]

My question for aluminum welding is, how much heat do you need if you just want to close up a hole in a machined aluminum part?

I find pre heat helps, but it needs a lot of torch heat to do it, and honestly a large propane torch is probably better for this (for heat output) than say MAPP or whatever. You'll lose whatever T6 heat treat in it anyways.

Also low frequency, it helps with penetration.

[tweake]

My question for aluminum welding is, how much heat do you need if you just want to close up a hole in a machined aluminum part?

for me its about getting enough to keep a good fluid puddle that wets out. your not trying to go for max penetration like with a joint, but you also don't want to have voids. this is where more focus is better but still run enough heat to drive it into the root. you want to avoid having a C in the root on the front of the puddle.

the hard part with aluminum is making sure the arc can get in there to clean the oxide. otherwise you can end up with trapped oxide. so often you need to bevel, or grind out a crack, or widen/taper a hole. if you leave trapped oxide in say a crack repair, it can just crack again. this can even happen on butt joins.

[cj737]

My question for aluminum welding is, how much heat do you need if you just want to close up a hole in a machined aluminum part?

That depends entirely upon the thickness of the material, the size/diameter of the hole, etc. Is it a blind hole of 6MM into a 30MM part? Is it a 2mm hole drilled through a 3mm sheet? There is no "standard answer" to your question.

I find pre heat helps, but it needs a lot of torch heat to do it, and honestly a large propane torch is probably better for this (for heat output) than say MAPP or whatever. You'll lose whatever T6 heat treat in it anyways.

MAPP is much hotter than propane. Its not as hot as Oxy/Acetylene or Oxygen/Propane, but pure propane is not that hot. And a preheat of aluminum will not destroy a T6 heat treatment. Welding it might, but that all depends.

[taiwanluthiers]

Only asking because my welder goes to 250 amp at most and I think it can really only do about 5 or 6mm of thickness. It also tops out at 120hz for frequency, and lowest is 40. I just find in thick parts I'm getting much better puddling performance at 40hz vs 120hz. It's not a miller or Lincoln, but none of those brands are available in Taiwan anyways, only Chinese brands. Even the instructions from the manufacturer tells me to use power frequency for thicker materials.

I do find puddling performance improves significantly once the part has started getting hot. Aluminum is a pain to heat, and if the part isn't so big placing it on a gas stove until it got to about 200 Celsius will often do the job. But for larger part, mapp and acetylene will be required to get the local area hot enough.

I also read 6061 isn't the best for welding but it can be welded, but 7071 can't be welded at all without cracking, it contains zinc. I saw a this old tony video where he tried to weld 7071 and it cracked immediately.

I can only get map pro, supposedly they sell mapp gas in china but I got no way to import it.

[tweake]

pre heat it with whatever you have.
unless its a huge thing the actual flame temp doesn't mean to much, your heating the whole thing not just one spot. if you wan to heat just one spot the hotter the flame you need.
trouble with aluminum is if you heat one spot that heat spreads pretty fast and it cools down.

6061 can be welded fine, tho there is easier grades. there is grades you can't due to zinc or other additives which will cause cracking issues. other grades require a certain filler material so the weld doesn't crack.

[taiwanluthiers]

I believe I use 4043 rods, and it doesn't seem to have too much issue welding 6061, but often getting good looking beads without grinding is a challenge on aluminum, especially if the thickness is different. I tried fixing an aluminum hand cart once. Plastic top handle broke off and I welded a solid aluminum bar to it. It was frustrating as hell and the weld looked like poop. I ended up filling the top of the hollow tube with filler, giving me a solid looking piece, and then grinding it smooth.

The aluminum also often wants to bead away when melting, regardless of ac balance, until I add filler or move the torch side to side.

The tungsten also looks like a mess. I was using 3/32 but it really needs 1/8.

I wouldn't fusion weld aluminum at all.

Titanium welding is so easy in comparison. It's like welding stainless except you really want a large cup and low heat input, meaning you high current tack it.

[tweake]

hollow tube will bead away when hit with to much heat. especially at the start. once its joined a bit then heat is draw away by the thick part to a degree. adding filler also adds mass which helps it handle the heat. thin to thick can be tricky as the thick part sucks away so much heat that you can't use low amps like you would on the thin part. so usually puddle it on the thick part then wash it up onto the thin. because aluminum sucks away the heat so much, there is a bigger difference between the thick to thin than with steel.

keep in mind many cheap goods are made from crap aluminum and can be a nightmare to weld. rough rule of thumb if the manufacture rivets it all together its probably not weldable.

only 5 series will fusion weld. other will a bit but are super weak. even on 5 series i would add filler.