How to TIG weld aluminum beverage cans together

I show how to weld aluminum cans together with a cheap import TIG welder. I am not a professional welder, so some of my advice may be unconventional or even wrong, but these methods work well for me. With a 3/32" electrode and large gas lens, I don't have to change the torch setup for nearly any kind of common welding. Let me know if you have any questions or would like me to make more welding videos.

Some things that I have learned:

Don't use pure tungsten electrodes. The new rare-earth blends work very well on nearly all metals.

Sharpen the electrode to a very fine point for low-current welding, and sharpen it like a pencil for higher (eg over 100A) welding.

Keep the electrode balance control electrode negative ("weld") and only shift toward electrode positive ("clean") when absolutely necessary.

The welder's pulse feature turned out to be not as useful as I originally thought. It just seems to complicate things. It's definitely possible to make great welds without it.

Use fat electrodes. Some people claim that using an electrode that is "too large" for the weld current will cause the arc to wander. Nope. Just grind it to a sharp point. Thin electrodes 1/16" and .040" overheat much too easily, and provide no apparent benefit. .040" electrodes are very frustrating.

Use thin filler rod. It's much easier to feed thin rod quickly than feed fat rod slowly. As I mentioned in the video, it's easier to sneak a thin filler rod into the puddle while keeping the torch close to the surface.

Three-way flow regulator for argon shielding gas

The serious TIG welders have two flow regulators on their argon supply -- one for the torch, and the other for the purge argon on the backside of the weld. I found some cheap flow regulators on eBay, and I made a manifold for the two I bought plus the original regulator. I've imagined situations where three regulators might be helpful like welding a gusset on the outside of a tank. The gusset would need backing gas in addition to the torch side, and the inside of the tank would need to be purged as well. Who knows.
I made the manifold itself out of a block of white Delrin with four 1/4-18 pipe threads cut into it. The original regulator (on the left) has 1/4-18 straight threads. I just ran my tap really deep into the Delrin so that the regulator would fit in. It's very easy to make metal fittings seal with Delrin and no Telfon tape is necessary. The Chinese argon pressure regulator also had a 1/4-18 female straight thread which was intended to seal on the end of the pipe. A regular 1/4" brass pipe thread nipple worked just fine and presumably bottomed out and sealed on its end.

Stainless TIG welding update

OK, I have learned a few more things about welding stainless steels with TIG. I am far from an authoritative source on the subject, but I hope to share what I do know:

* Keep the weld bead width as thin as possible. This is really key to everything else, and making a thin weld bead will force the welder to do everything else correctly (ie keep the current to a minimum, keep the electrode close to the surface, etc).

* Minimize the heat input to the work by any means necessary: Lower the amperage, bring the electrode closer to the surface, use copper chill blocks, stitch-weld 1" sections and allow the work to cool between welds.

*Keep the tungsten electrode sharpened to a needle-point. The length of the taper should cover about 2.5 times the electrode diameter, and I normally leave the tip fully sharp for low-amperage welding. I've never had a problem with the tip breaking, and it helps direct the arc.

* The part fit-up must be superb. I always try to tell myself "sure, I can fill that gap", but no. With stainless, filling the gap means dripping lots of filler rod, which will be very hot and leave the weld in very bad condition. The excessive heat will "burn" the chromium out of the alloy.

* The electrode should be as close to the surface as possible. This is not an exaggeration. I mean really get the electrode as close as you can without touching the puddle. A small, hot arc is much more effective than a large cool arc.

* Use thin filler rod. If you're welding 1/16" thick stainless, I'd say the weld bead should be 1/8" wide or less. This will be a problem to weld with 1/16" rod, because it is difficult to dispense a small enough amount of rod to keep the bead thin enough. Additionally, since the electrode is being held very close to the surface, there isn't much room to stick the rod into the puddle. Using .045" and .035" rod is a HUGE help.


* Don't let the arc melt the rod! When adding rod, move the torch backward a tiny bit so that you can dip the rod into the puddle, then pull the rod out of the puddle, and advance both of your hands forward in the weld direction. I can tell that I've messed up when I see the rod form a ball on the end, and the arc changes color. If the weld is important, I would cut the end off the rod and start again.

* When the weld is all done, check the colors to see how corrosion-resistant the weld will likely be:

Gray, pinkish-gray, black = Not good. The stainless has been chemically changed at the surface
Dark blue, purple, turquoise = Borderline OK. Acceptable for some situations.
Gold, silver = Perfect.



* The most common fill rod for welding stainless is 308. As near as I can tell, 308 can be used on anything, but it would be unwise to use it on higher grades of stainless like 316. I tried both 308 and 316 fill rods on 304 base metal. They behave pretty similarly, but 308 seems to melt a little more easily.

* Most rods and base metals can be obtained with an "L" designation, like 304L or 308L. These are low-carbon alloys and are preferable over the non-L alloys because welding can cause carbon to precipitate in the metal. The upshot is that welding 304 will have a more deleterious effect on its corrosion resistance than welding 304L. How important is this effect? I don't know. All of the information that I found on the net was purely anecdotal and poorly documented.



This was attempted with 1/16" filler. Very inconsistent bead width.


This was done with .045" filler. It's not perfect, but much better. Both welds were stitch-welded in 1" sections.

Welded tube joint (mild steel)

This is a joint which would be found on a typical bicycle. I used a 7/8" hole saw mounted in my milling machine to notch the end of a tube. It fits up against another tube of the same diameter. I TIG welded at about 80 amps with a standard #7 gas cup, 15 cfh argon, 1/16" tungsten and rod.

The tube was originally chromed, but I ground the chrome off prior to welding.

After welding, I ground one side of the weld flat. Is this structurally sound? I don't know.

Monster TIG nozzle = monster waste of money

UPDATE 6/15/2013: Arc-zone has redesigned their Monster TIG nozzle. It now has a chunk of rock wool or similar material to help diffuse the gas flow. I have never used this version, and so the comments in this blog post do not apply to it. Check the comments section for more details.


Today's lesson involves my quest to weld stainless steel sheet metal, a Monster TIG nozzle, and a copper chill bar. In previous posts, I've described having trouble maintaining weld bead quality on thin stainless sheets. The problems are a combination of putting too much heat into the metal, and having too little argon gas coverage. I am not sure if addressing one problem can help solve the other. Today, I did some testing to find out if adding a lot of gas coverage can help. I also tested out a copper chill bar.

Common weld parameters for the whole test:
1/16 ceriated tungsten ground to a sharp point
55 amps (pedal floored for the entire test)
very slight %90 pulse at 200Hz just to get my auto-darkening helmet to work
20 CFH pure argon
10 sec post-flow

I purposefully used a small piece of 304 1/16" sheet to show the heat buildup problems. I also welded close to the edge to test the worst-case heat buildup.

First up: normal gas lens with #8 cup.

Wow, I never knew the copper could help that much!

Next, a large diameter gas lens with #12 cup
Same story here. It looks like there was even less heat in the metal. This might be because there was better contact between the sheet and copper, or because the gas nozzle has a wider opening. I'll bet the Monster nozzle will be even better...

Finally, the "Monster TIG nozzle", which is 1" in diameter and uses a stubby gas lens collet body.
Wha?! There must be something wrong -- what's going on here?! I tried all gas flow settings from 5 CFH up to 30 CFH and concluded this nozzle is completely useless. It's possible that I am misunderstanding something since I am a new welder, but I am pretty sure this thing just plain doesn't work. I noticed that the tungsten had turned black after a few welds, indicating the gas coverage isn't even enough to keep the tunsten from oxidizing. At 30 CFH, the gas flow was so turbulent, I could see the arc getting blown around, and pops of smoke coming out of the weld. At lower flow settings, I could see the stainless oxidizing even before I lifted my hood. I tried different stickout from 1/8" up to 3/4" with no change. I am sure the cup made good contact with the torch body, and there were no air leaks. I even tried extending the nozzle away from the gas lens with a spacer to make sure there was adquate space for the gas to disperse with only a tiny improvement.

On the right: large gas lens with #12 cup. On the left, you guessed it, Monster suck.



This screen arrangement doesn't look so great.

It's made with just two screens without any spacers between them, and two very coarse screens on the outsides. The screen diameter is a few mm less than the interior diameter of the ceramic cup, so I'm guessing a lot of gas slips around the edges of the screens.
So, I'll be continuing my stainless welding quest without the Monster nozzle and with copper chill blocks. I'll also be testing Solar Flux B. So far, I think it works well but poses a huge cleanup mess after the welding is complete.

Bent TIG electrode = trailing shield?

Do you think this looks messed up?

Check out the welds that I can make with the messed up electrode. This is 1/16" 304:
I purposefully bent the electrode in the direction that I was moving the TIG torch. That way, there was a lot more gas coverage behind the arc than in front. It worked wonderfully! Even near the edge, the heat buildup was much less of a problem. I think the next step will be to make a trailing shield for the torch. Trailing shields are available, but only for amazingly high amounts of money. One alternative might be the "Monster nozzle". It could be large enough to act as a trailing shield.

Improved stainless welds with large gas lens

My new TIG parts just arrived today, and I had to do a quick test. In short, the large gas lens makes a huge difference. Take a look at this beast: #12 cup with "large gas lens" and 1/16 tungsten


I am using the same exact 1/16" thick SS304 sheet metal that I have been practicing with all along:

Compare that weld bead to the pair of beads in my previous post. All settings are exactly the same except for the gas lens. Well, I guess I was using .040" tungsten in the previous post, but that should have helped if anything.


Here's a few more. I've heard that "salmon color" is the best thing a stainless welder can hope for. I changed the flow rate from 10 to 20 CFH going from top to bottom -- not much difference. The bottom bead had a longer post-flow, so the tail of the bead has less purple/blue.

The backsides of these welds are pretty messed up. I'll report about the Solar flux later.

First attemps at TIG welding stainless steel

I've spent most of my TIG welding practice time on aluminum, but have recently started to experiment with stainless steel (all 304 for now). It's difficult! Most welders say that aluminum is the most difficult because it liquefies quickly and has oxide layer problems, but in my opinion, stainless is more difficult because of the shield gas requirements.
Here's my setup:
.040" tungsten -- my local welding shop convinced me to try this instead of 1/16" tungsten. They somehow thought I could weld with less heat while using .040". I didn't understand it when they explained it so me, and I still don't -- especially since it makes no difference that I can tell.

no. 8 cup with gas lens

less than 1/4" stickout




Here's a 1/16" thick 304 sheet. The upper bead was done with 10CFH argon, the lower bead was 20 CFH. The picture shows the front and back of a simple bead with 1/16" filler. I was using as absolutely little heat as possible, sometimes solidifying the weld pool as I moved, making for an irregular bead. These beads both have major problems. They are pretty gray except on the left side where I finshed the weld and the post-flow cooled off the bead. The rest of the weld cooled outside of the gas shield, turning it gray, which is bad because the structure of the stainless steel has been altered. This will likely lead to corrosion or stress cracks.

I prepped the left side of the top surface to see if it would be any different than the un-prepped right side. The metal has a smooth almost plastic-like feel, so I was unsure if this was normal. It didn't seem to make any difference.

The backside shows major problems too. The upper bead looks better because there was more sheet metal all around the weld to soak up excess heat. The lower bead is "sugared" because it got very hot in an oxygen atmosphere. The weld is close to the edge of the sheet metal, so the heat built up more quickly.

To attempt to fix the topside problems, I've ordered a "large gas lens" setup with some huge gas cups from an online welding store. I tried to order these parts at my local welding shop, but they didn't have them, and were somewhat hesitant to even order them for me. I have no idea if the large gas lens will work, but the parts are relatively cheap.

To attempt to fix the backside problems, I've ordered some Solar Flux B, which was originally made for gas welding stainless steel. The alternative to flux is to build an argon purge for the backside of welds. This purge could be a box, a nozzle, or some other device to make sure the backside is flooded with argon. The problem is that every weld situation (tubes, sheet metal, angle, etc, etc) requires a custom purge setup, and argon isn't exactly cheap either. I'll definitely be posting more information about the flux in the coming weeks.


Here's a weld made on thicker (about 1/8") stainless. The grade of stainless is unknown. Don't mind the soot. I was just too lazy to regrind my tungsten after I hit it with the filler rod. Notice the bead is NOT gray. The thick metal is able to pull heat out quickly enough to prevent problems. Unfortunately, most of my stainless welding will be on tanks and tubes that will never be 1/8" thick. I need to find a solution that will work down to .049" at least.

Aluminum welding progress

I ordered a bunch of aluminum parts from eBay and McMaster. I've spent a few afternoons just cutting the metal into random parts and TIG welding it back together


I've made a few coupons to test the five basic weld types:

* Butt
* T-joint
* Open corner
* Lap joint
* Edge

The above picture only shows a T-joint and open corner, since those are my best types.



This pipe doesn't do anything useful, unfortunately. I just made random cuts on my miter saw, rotated the two pieces 180*, then welded them.


I'm still working on getting nice, consistent beads, but they have good penetration, and I'm getting a lot more confident with aluminum.

Aluminum welding progress: T-joint

I ordered a bunch of aluminum bars and cut them into 6" pieces to practice basic welding joints. It's going pretty well. Here's a list of quick tips that I have learned:

1/16" electrods seem good enough to handle almost any task at 150A or less. I'm not yet sure why anyone would use anything bigger or smaller for less than 150A.

The filler rod must be forcibly pushed into the puddle, then quickly retracted. It cannot be brought near the arc slowly, as it will melt before it gets to the puddle! I have found that I move the torch in the direction of the weld to get the base metal molten, then move it backwards slightly while I add filler, then move forwards again. I use this one-step-back, two-steps-forward approach for the entire weld.

The AC balance control can be pretty heavily shifted to DC EN. I usually keep mine at %70 to %80.

It helps to have the part propped up off the table. For the first T-joint that I welded, I had the plat laying flat on my metal table. This makes the angle of the torch more difficult, but worse, it sucks a lot of heat out of the aluminum that is touching the table. This is really a pain, because it makes the weld asymmetric in terms of heat required, and finding the magic torch angle to melt both sides evenly becomes more difficult.

Harbor Freight welding auto-darkening hood

Harbor Freight sells an auto-darkening welding hood (Item# 46092) for about $50 -- depending on the current sale. It is cheaply made (of course), but not ridiculously so, and has proved to be worthwhile to me. However, I had a very unusual problem that I could not find documented anywhere else on the 'net. Hopefully my blog post will help others in my situation.

For the first month I owned my TIG welder, I only welded aluminum. That is the main reason I bought the machine, and I was practicing quite a bit. Eventually I got curious about stainless steel, and switched the machine over to DC and tried some welds. I'll write more about welding stainless in another post, but the first thing that I noticed was that my welding hood flickered badly during the welds. Strangely, at low power arcs (10-20 amps), it was dark all of the time, but when I cranked it up to 150A, the lens would be become clear, and only ocassionally flicker into the dark mode. At the time, I didn't make the connection between using DC mode on the machine and the hood flickering. It had been a week since I last used the machine, and there seemed to be no reason why DC would cause the hood to fail. I also noticed that aiming the hood at a normal fluorescent light would cause it to darken. I thought the thing must be broken.

I took the hood apart and looked at its circuit board: 3 opamp ICs, 2 logic gate ICs, an oscillator, and two ICs that had their numbers scratched off. The board itself is multi-layered with an apparent ground plane on the bottom, so determining the wiring between chips is damn near impossible. I was expecting to find a soldering problem, dead battery, dead solar cell, etc, but all testable components were good. After connecting my oscilloscope and learning a little about how auto-darkening hoods work, I decided to return the thing. I figured one of those unmarked ICs might have fried. Harbor Freight gave me a new hood and tried to sell me a 2-year warranty. When I politely declined, the saleperson smirked and said "I'll sell you another one in 6 months." Gotta love Harbor Freight.

I really expected the new hood to work properly, but alas it flickered in exactly the same manner as the first hood. By this time, I had noticed that the hood worked flawlesly for AC welding, was darkened by fluorescent lights, and even was darkened by me waving my fingers in front of the sensor. It was NOT darkened by pointing it at the sun, or a DC welding arc. So, my conclusion was that the hood only responds to high-frequency changes in light -- not high-intensity changes. Apparently, the DC arc on my inverter welder is so stable, it does not have enough ripple to cause the hood to trigger. The solution: I set the machine to "pulse" at 200 Hz, with the background current %90 of the peak current. The current pulsing is so slight, that it doesn't really affect the weld, but it is enough to reliably trigger the hood.

TIG welding aluminum cans together

Take a look at this:

I've always been impressed by people who could weld soda cans together, and so I gave it a shot today. It's actually easier than I thought. The cans act as great heat sinks, and the bottom of the can is a rolled "edge" (ie it would be MUCH more difficult to cut a can in half, then butt-weld the paper-thin aluminum edges together). Of course, my weld is not really pretty, and I did blow through the material on the other side of the can... This exercise reminded me how much I need to work on holding the torch at 90* to the surface when going around a cylinder.

Everlast 200A TIG welder: welding aluminum

Here's the parameters for AC TIG welding aluminum (about 1/8" thick 6061):

Torch setup:
1/16" ceriated tungsten electrode
#6 gas cup
3/16" of electrode stickout
electrode is ground into a sharp point

Gas:
pure argon at about 7 lpm or 15 cfh (The Chinese regulator reads out in lpm, not cfh !)

Welder:
No pulse
75% electrode negative balance
5 s post-gas
Zero arc force
Max amperage of about 100A

Rod:
4043 1/16" or 3/32"

In order to strike the arc, I usually have to push the pedal pretty far down, sometimes all the way. Having a really clean, sharply-ground electrode, and a really clean metal surface will make striking an arc a lot easier.


Here's some points that I learned from my first few hours playing with the machine:

Arc force: This control is only useful for stick welding, not TIG. I searched the internet for a long time trying to figure out what this control actually does. Here's the best explanation:
http://www.millerwelds.com/education/articles/article108.html This "arc force" control is also called "dig" and describes how forcibly the stick welding arc can push material away. A high arc force setting will boost the arc current when the machine senses the arc voltage is dropping too low (meaning a short-circuit is about to happen). This boosted current blasts away base metal and rod, preventing the stick from welding itself to the base metal. Anyway, I had no idea about this control for the first few sessions that I used the TIG welder, and left it all the way up (50A). I noticed that it made striking the arc much easier. On thick materials, this was not a problem, but on thin stuff, I would blow through the material upon striking the arc. The arc force control is supposed to be enabled only for stick welding, but that is not the case on this machine (super200P). During TIG welding, I assume the voltage is low enough to cause the arc force control to set a "minimum" amperage of 50A, which is why it was a big problem for thin material. For TIG welding, be sure the arc force control is turned all the way down!

AC balance: This machine has a strangely configured balance control. The range is %20 to %80 electrode positive. It's unusual to indicate the electrode positive percentage, and anything over %50 positive is considered not useful at all. I am sure there are crazy situations that require it, but the electrode melts so easily, and the base metal has such a huge etched area at those levels, I can't see it ever being that useful for common operations. So, never set the balance past %50 even though the machine's range makes it seem like it might be a useful thing to do. In fact, having a minimum of %20 electrode positive is still quite a lot. It would be nice if the machine went down to %5 or %10.

Gas flow: The Chinese flow meter is calibrated in liters per minute, not cubic feet per hour. Watch those units! lpm is approximately half of cfh.

Electrodes: No one uses pure tungsten anymore. The information on the web is old, and repeated by people who have never used modern electrodes or modern welders. You can weld all common metals with a ceriated electrode ground to a fine tip. The tip will round-over a little bit during AC welding, but there is no point in "balling" the tip of the electrode. All it does, is make the arc difficult to control.

Pulse feature: I have tried it a few times, but I haven't noticed any big difference in welding ease or speed. I'll try it later, and write more about it.

Finger-tip control: After using the welder for a while with the pedal, I switched to the plasma cutter, and hooked up the finger-tip control switch. It didn't plasma cut. The machine would not strike an arc at all. After futzing for a long time, I hooked up the pedal control (even for plasma cutter), and it started to cut like a dream. I tried the same for the stick welder setting, and it too, required the pedal to be connected in order to weld. It seems the finger-tip control circuit in the welder either died, or never worked properly. Hmmm. I'll bet this has to do with the "background" "max" and "arc force" settings.

Everlast 200A TIG welder: first impressions and review

So, I finally decided to buy a TIG welder after many years of waiting and searching craigslist, hoping to find a used machine for a reasonable price. Unfortunately, most transformer-based (old) used machines are enormous and extremely heavy, and they are more difficult to use than modern inverter-based machines. Finding a used inverter machine is possible, but the price for a used 200A AC inverter TIG welder made by an American company is at least $2-3,000. That is much more than I am wiling to spend on a hobby. So, the alternative is to buy a cheap imported machine off of eBay. I also decided to split the cost of the machine with a friend, making it a very affordable to get started with TIG welding. I know that some poor soul in China is probably making $1/day just so that I can have a welder, but I really can't justify an extra couple thousand bucks on the American machine without knowing intimate details about how the American and Chinese companies are run. Anyway, enough politics. On to welding!

I bought the 200A pulse TIG machine with the plasma cutter feature. This is advertised on eBay by a number of different sellers. I bought mine from Everlast, who is located very close to me in San Mateo, CA. I drove up there, paid by credit card in person, and brought the machine home.

The machine was packed well, and came complete with all accessories (including an argon regulator) except tungsten electrodes and collets.

I also bought a 40 cu-ft Argon bottle from a local welding supply store, which I exhausted very quickly. I was supposed to get 2 hours of pedal-down welding time out of that bottle, and I might have, but it sure seemed to disappear fast. I upraded to an 80 cu-ft bottle, which is the largest size that I can easily lift.


The Chinese argon regulator scared me a little bit since it is going to be holding back over 2000 psi of gas, and could be a hazard if not built and tested properly. To my surprise, it actually seems to be built exceptionally well. It has a good heft to it, and regulates the gas flow very easily and accurately. It has not given me any problems at all, and I am not worried about it.

The torch itself is a pretty standard air-cooled model. It came with a selection of gas cups, and short and long back caps.




After a few hours of practice, these are my best aluminum welds (6061 sheet with 4043 filler), open corner weld. The top photo is 1/8" sheet, the bottom is 1/32"

In later posts, I will talk about specific machine settings. Overall, I am very happy with this machine, and would recommend it to other people looking to get started with TIG welding.

Search my blog for other TIG- and welding-related stuff.