[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.

[Timmy_Tiggs]

I have 2 absolute horror stories of welding aluminum that is way too thick for the available amperage, but I'll save those for a different thread.

A "most brutal welding jobs" thread.

[Joshua031]

I found this topic on Google and thought I'd join the conversation. I'm a hobbyist welder, learning more about TIG welding techniques and eager for advice! Are there any tips on how to best set up the machine for welding 1/4-inch aluminum with limited amperage?

[tweake]

I found this topic on Google and thought I'd join the conversation. I'm a hobbyist welder, learning more about TIG welding techniques and eager for advice! Are there any tips on how to best set up the machine for welding 1/4-inch aluminum with limited amperage?

for the machine i recommend low frequency, the least amount of cleaning action you get away with, small diameter normal cup (ie no gas lens) and if your machine has it, mix tig.
also make sure your grounds are really good. ground it directly to the part.

[cj737]

I found this topic on Google and thought I'd join the conversation. I'm a hobbyist welder, learning more about TIG welding techniques and eager for advice! Are there any tips on how to best set up the machine for welding 1/4-inch aluminum with limited amperage?

If you provide more details about your machine, the material you are using (plate, tube, solid bar) and what type of joint configuration (T, lap, fillet) and what you are welding to (same thickness, different shape, etc) then we can suggest all types of help.

You’ll need >170 amps to weld 1/4” aluminum. Without those amps, you can’t keep the part hot enough to get proper penetration of the weld. You can preheat the material with a torch and gas of your choosing, but you’ll still need some high amps.

You don’t want to weld with less than 60Hz. Going lower can be done, but with high amps and really low frequency, you’ll tear the tungsten up because the cycle rate is too slow. That’s why some folks “ball” their tungsten with a Hz of 30, then change back to 90-> and weld.

The positive side of the wave is performing the “cleaning” and the negative side of the wave is performing the “penetration” if you think about it in those terms. You need to keep blasting the oxide layer to get the penetration because the oxide layer melts at a much higher temp than the base metal.

[cj737]

There is much debate about which frequency is best to weld aluminum with. For me, my experience stems from a top tier engine builder who welds up aluminum blocks, very large industrial boxes, etc. He demonstrated to me that the higher the frequency, the better the outcome. It is his contention (and experience) that using a very high frequency keeps the arc more stable as it switches between NEG and POS so that the oxide layer is more frequently being eroded and the penetration time of the arc is able to hit the base.

There are some other factors in deciding on frequency. The etching zone will be smaller with a higher frequency. This can be a desirable outcome, other times it may not matter. It produces a more “focused” arc so pinpoint heat control is better. Higher frequency is commonly preferred for edge welding, build-up work, and thinner material for “focus” of the arc and controlling the heat dispersion.

All of this comes with the extreme caveat; your mileage may vary! Like all things welding, there is not single answer. Each person and each machine behaves slightly differently, the quality of the metal matters, the joint configuration really matters, and sometimes the position has another significant influence. So, the very best advice I can offer is to EXPERIMENT with what works for you and your situation.

The same holds true about cup size and tungsten size. I know guys who stick a 1/8” tungsten in and weld everything from 0.040 steel to 1” aluminum and never change. They will weld everything with a #7 cup and never look back. I change cups alot. I do tend to stick to 3/32 tungsten unless I am doing high amp, long duration work (marine fuel tanks for instance). I use a 1/8” #5 setup with my water cooled #20 torch, set the machine to 200 amps, 250 Hz, and smash 1/8” filler in all day long.

With a #5 cup, you do NOT need a gas lens; a standard collet body works perfectly well. So there is some gas savings there, but in fact the gas volumes matter very little in the long run. Preflow and postflow are your friends, and keep the gas CFH high enough to produce clean, shiny welds. You’ll get better penetration, less “redos” and save time (which is a great deal more expensive than gas).

Hope this helps-

[Timmy_Tiggs]

"There are some other factors in deciding on frequency."
Our ears? The kind of stuff I usually do is fine with 90 Hz. And of course, we did everything with 60 cycles in the 20th century.
I turn up the frequency to prevent overpenetration. Otherwise, 90 to 120 seems to work fine.

[cj737]

I turn up the frequency to prevent overpenetration.

This an example of a debated topic. With a frequency of 400Hz, I can get the same, if not better, than at 90Hz. How? Why? To understand that you have to examine what the frequency is actually doing to the electrons and the switching from EP to EN.

You might need more amps with a higher frequency, but not always. It depends on many factors. Yes, high frequency is pretty shrill and ear plugs are often in my ears (anyway from other shop noise). But I also use a 25’ cable so distance helps.

The biggest merit of high frequency is keeping the oxide layer under constant assault. By switching faster, you disrupt the oxide layer and put penetration in faster, but for shorter amounts of time. That’s why distortion is also less with higher frequency (in my experience).

So as I said above, experiment and find out what works for you. Inverters offer lots of advantages over transformers so to limit your approach with a modern machine to an older version of craftsmanship is overlooking possible advantages.

[tweake]

I turn up the frequency to prevent overpenetration.

This an example of a debated topic. With a frequency of 400Hz, I can get the same, if not better, than at 90Hz. How? Why? To understand that you have to examine what the frequency is actually doing to the electrons and the switching from EP to EN.

You might need more amps with a higher frequency, but not always. It depends on many factors. Yes, high frequency is pretty shrill and ear plugs are often in my ears (anyway from other shop noise). But I also use a 25’ cable so distance helps.

The biggest merit of high frequency is keeping the oxide layer under constant assault. By switching faster, you disrupt the oxide layer and put penetration in faster, but for shorter amounts of time. That’s why distortion is also less with higher frequency (in my experience).

i don't think "keeping oxide layer under assault" is a thing. once its cleaned its under gas coverage and not reforming. think of mix tig when its switching between ac and dcn.
the only thing with higher freq is you get more HF, which if course fires every time it swaps from en to ep. that may help with cleaning a bit.
otherwise with higher freq you get more times its at zero amps. it takes time for heat to travel through material, so if you do short bursts it won't travel far compared to a long burst. hence lower heat input which gives lower penetration and less distortion. turning off the pulse before the heat as traveled far also reduces distance so the weld is smaller, more focused.
it should be far more noticeable on sinewave or triangle wave. square wave (tho most are not a true square wave) has the least zero/low amp time when it changes. how long depends on quality of the components.

i have no idea why yours would be worse at 90hz, maybe thats something with your setup ?? difference in HF?

the other thing is how much heat you can get on the positive side. the small cup and not being a gas lens helps improve that. (its a noticeable difference going from 8 cup gas lens to 5 cup normal). gas flow rates can also play a role in that.

for me, i was doing a weld a while back at 500hz and was wondering why it was so cold even tho tons of amps. dropped it down to 150hz and its a ton more heat. night and day difference. i very regularly use higher freq doing pulse welding on stainless tubing to reduce the heat so i can wind up the amps and have decent range on the pedal. i'll run double the amps. my cheap machines don't run well a low amps.

[cj737]

i don't think "keeping oxide layer under assault" is a thing. once its cleaned its under gas coverage and not reforming.
If the electrons are switching at much higher rate, then the oxide layer is constantly being eroded (hence, assaulted)

otherwise with higher freq you get more times its at zero amps.
I am unaware of any version of a sine wave that pauses at 0. All waves pass through 0 but at no time would you actually have 0 amps running through the arc (at least not in any measurable amount of time that would affect the arc).

i have no idea why yours would be worse at 90hz, maybe thats something with your setup ?? difference in HF?
I stated the reasons why I can get better or same results. I guess it depends upon what is determined to be “good”, “good enough” or “the best I can do”.

the other thing is how much heat you can get on the positive side.
On EP you’re not putting heat into part, your pulling electrons through which is the cleaning action from the part towards the tungsten. EN is putting heat into the part.

for me, i was doing a weld a while back at 500hz and was wondering why it was so cold even tho tons of amps. dropped it down to 150hz and its a ton more heat. my cheap machines don't run well a low amps.
Perhaps you have a setup issue or a cheap machine? Oh, I see you do. So perhaps that is the issue.

[tweake]

i don't think "keeping oxide layer under assault" is a thing. once its cleaned its under gas coverage and not reforming.
If the electrons are switching at much higher rate, then the oxide layer is constantly being eroded (hence, assaulted)

otherwise with higher freq you get more times its at zero amps.
I am unaware of any version of a sine wave that pauses at 0. All waves pass through 0 but at no time would you actually have 0 amps running through the arc (at least not in any measurable amount of time that would affect the arc).

i have no idea why yours would be worse at 90hz, maybe thats something with your setup ?? difference in HF?
I stated the reasons why I can get better or same results. I guess it depends upon what is determined to be “good”, “good enough” or “the best I can do”.

the other thing is how much heat you can get on the positive side.
On EP you’re not putting heat into part, your pulling electrons through which is the cleaning action from the part towards the tungsten. EN is putting heat into the part.

for me, i was doing a weld a while back at 500hz and was wondering why it was so cold even tho tons of amps. dropped it down to 150hz and its a ton more heat. my cheap machines don't run well a low amps.
Perhaps you have a setup issue or a cheap machine? Oh, I see you do. So perhaps that is the issue.

i don't think freq makes any difference to cleaning action. maybe its something worth testing. i would have to look through the white papers a bit to see if thats been studied.

at zero volts there is zero current flow. need volts for current to flow. thats why it has HT , to keep the arc lit at zero cross over. try ac tig welding with no HT working.
also igbt don't turn on/off at zero, usually a low voltage. so there is actually time when there is no useable current flow happening. the higher the freq the more zero cross over points there are, the more off current time there is.

on ep some heat goes into the part. thats to do with ionization of the argon. thats why smaller cup works better as your focusing that ionized gas flow to the weld pool. also why normal cup works better than gas lens, the disrupted tumbling flow gets ionized a bit better than the nice laminar flow of the gas lens.

now now, no cheap shots at my poor cheap machine. they work well enough.
besides jody and others have vids on higher the freq the less penetration it does. jody's vid is quite good as its on a positioner so it removes operator speed out of it.

[Timmy_Tiggs]

I turn up the frequency to prevent overpenetration.

Yes, high frequency is pretty shrill and ear plugs are often in my ears (anyway from other shop noise). But I also use a 25’ cable so distance helps.

I have a 25' cable also, but that doesn't help since the sound comes from the oscillation of the arc at the torch, not the machine.
Try this: Weld at 250 cycles (max on my machine). Place a 4'x'8' sheet of corrugated cardboard between the machine and yourself and see if you can tell a difference. Spoiler alert: You can't. I just tried this, BTW.