Ask your WELDING questions here.

[clintnz]

Originally Posted by David R

Been using a fine 4" belt sander with the electrode chucked in a battery powered drill turning slow.
This cleans up the tungsten even above the point.

I then dress them on a Sharpie which is a dremel with a diamond wheel.

I could live with out the sharpie if I had to.

For the guy with a new tig welder on its way. Enjoy it.

Cheers, I have a belt sander so I'll give it a try. I unpacked & set up the new toy yesterday, It's a multifunction 200A Mitech. Ran though the functions quickly to check everything worked, Stick, AC, Pulse, DC, Plasma all seemed to do their thing. Tonight we will get it dialed in all proper like as per the Miller Handbook I have & start out Tigging on a few different thicknesses of steel.

Cheers
Clint

[clintnz]

This is my 3rd weld on alu with the new toy:



6mm plate, 160A base current, 200A peak current, pulse @ 35Hz, 50% width, 40% cleaning 2.4mm electrode, 2.4mm filler rod, 20 lpm argon. Pulse & cleaning settings are a bit of a guess.

Obviously my starts & stops need some work but I was surprised how good it looked given I how uncoordinated I am with the torch & rod. Any comment? Are the black spots of slag just a result of dirty metal or is there something else causing that?

Will play around some more tonight.

Cheers
Clint

[ER70S-2]

The black spots are probably dirt. Although 40% will clean off the oxide coating, it won't clean off the dirt.
I use a dedicated for alum only, 3" stainless brush in a drill to clean alum. Like soldering, the cleaner the alum, the better the puddle will wet (flow).

[Toysrme]

Remember that heat input is directed by the A/C bias the cleaning action cycle (DCEP) dumps 2/3 of it's heat into the torch, not the base metal. By decreasing your cleaning bias you effectively increase the average temperature of the workpiece without changing anything else, but the cleaning action itself suffers greatly.
Aluminum is protected by aluminum oxide. The base metal ALWAYS, and even the filler rods if they're old/been exposed too much. This must be cleaned off with a stainless wire brush before welding (and never use it for anything but aluminum). Don't use sand paper to clean it, most are aluminum oxide abrasives and that just doesn't help you any. ;)
brush with a stainless steel wire brush
wipe with acetone (always wipe your rods with acetone also)

If you prep aluminum, it needs almost no DCEP cleaning cycle. Only enough to vaporize the exposed aluminum oxide formed on the skin of the base metal & filler.

Take this constructively. <3
Without being nit-picky & just trying to teach you as I'd tell an employee/fellow worker i am inspecting or a student
For the weld itself. :

• your torch is in the wrong position as you travel, keep it centered along the joint please
• your torch must be held vertically above this joint. you are drifting off into an angle. this is why in the picture the left side of your bead has broken down correctly to the base metal while the right side is having issues
• your torch travel angle is a little inconsistent
• your rod position is a little off, but not bad
• your bead spacing is fine
• your beads could be a little less material added, but i wouldn't sweat that
• lastly, you're way too cold, even with the pulse.

try to keep your torch more stable with regards to angle and travel angle.

For your settings:

• 12.5lpm in a cup, 6-8lpm with a good gas lens
• i wouldn't run a back side auxiliary gas line for this kind of project.
• You really should be prepping that base metal surface a lot better
• You really don't need that much cleaning if the base metal is clean. 20% is where you should probably run it if you can. (and run 20% with a sharp+trunctuated tip just like you would steel, NOT a balled/blunt tip...)
• A trained welder would be welding this joint in the 240-260amp average heat range. I would personally weld that at around 260-270amps (without the pulse) so I could deal with the diamond plate if need be, you can always back off on the pedal.
• If you're not comfortable with what you're doing, use pulse and set the average amps to 200 and your peak to 240-260'ish so you can slow down & watch more.
• If you can change the frequency control off 50/60htz, then I would suggest 100/120htz or higher

All that being said. If somehow you were hallucinating in the desert, had a tig & forgot your stainless brush to clean the base metal... It would be more acceptable for you to increase the cleaning action bias to (likely) above 50% and increase the average heat input to compensate. ;)

[Toysrme]

Originally Posted by Toysrme

flipping through the thread i looks like yall have done a few nice projects.

I may not be on here too much, but if anyone needs some advice or has some questions, trouble or just needs advice & can't get answers shoot me a PM. if i can't answer a question, i likely know someone else who can :)

did all the welding schooling, inspection, engineering blah blah. retired from the boilermaker's, spent the better part of 2 years traveling the USA doing odd-ball performance/tuning projects before the economy totally ran out. (From turbocharging 125cc lawnmowers on the low end to building & tuning prototype a couple open wheeled cars for Formula Ford)
done a lot of work on 316 stainless



copper-nickle


BIP



gtaw/gmaw/fcaw/smaw/paw, CNC, w/e.

<3 adv

[clintnz]

Thanks for the tips guys, especially Toyrme, your detailed reply is much appreciated!

The machine is only 200A so I am aware 6mm Alu is at it's limit, I'll be practicing on some thinner stuff next. The machine is high frequency but there is no adjustment of AC Hz. I have a foot pedal but will probably concentrate on my torch & rod technique for a couple of sessions before I plug that in so as not to overload my wee brain

Cheers
Clint

[Toysrme]

NP!

stick the foot pedal on it. running tig without heat control takes half its advantage away for the average guy.
two trains of thought:
1) new people like setting the foot pedal / machine so that the maximum output is only slightly more than you need. this means you keep the pedal mostly floored the entire time & can pull heat really quick when you "oops"
2) other people will set it up well above what they need so they don't have to floor the pedal
new pedals can be crazy stiff, but put it on anyway. set the machine/pedal a bit more than you need, get situated and start the arc. then roll into it until the puddle is correct. then go.
keep in mind that without heat control the only way to adjust the heat is arc length (longer=colder, and that also affects your shielding gas coverage on your base metal, tip & filler!) and travel speed (less time in an area=less heat!). this is bad for the beginner because you just don't have the brain power to go fast enough! the limit adjustment is bad because the metal temp will change as you travel. the closer you get to any edge/end of the base metal the more heat builds up!
plus, if you don't fill & back off puddles slowly enough you can get some crater cracking. probably the #1 or 2 cause of failure with aluminum welds.

you can fix anything but with heat control (finger/torch/whatever) the process goes. beginner = still fudges but the fudge isnt as bad. some experience = knows youre about to fudge & stops before it happens. experienced = you avoid it all together
so plug that pedal in! =D

the machine is LF, so a lot of the heat is wasted heating your electrode. So point your electrode & then half blunt & ball it all old-school.
because of that, youll want to just run more heat. whatever you can. if you can give it another 20 amps on the average amperage then that's 20 amps more to the better :) itll force you to speed up a hair, but that's not a bad thing. you can stop as much as you like to get your bearings. tack the ends & stitch weld it every 1 1/2" if you want too as long as you're still breaking it down & fusing.

[clintnz]

Unsurprisingly, thin stuff is a little more difficult...



This is 3mm, butt welds. Much more practice required but while these are pretty ugly, they are less ugly than my earlier runs seen underneath.

This was the electrode, 2.4mm Zirconiated:



Welder settings, although I was dicking around with these a bit:




Being a Chinese machine the relationship between the dials & the actual outputs is not certain

I haven't found much info on pulse settings, so there's a good chance they are totally wrong. Some pointers on where to set those dials would be much appreciated, I do seem to be able to put down a tidier weld with the pulse on.

Is it normal for an Argon regulator to bleed off a little gas while the welder is stopped but the bottle tap still on? Doesn't seem right to me.

My girlfriend Rosie is rather liking her new toy. She has just started learning MMA & is finding the smooth DC much nicer than my old buzzbox:



Cheers
Clint

[Toysrme]

No! you should NEVER be bleeding gas EVER. Very common problem with chiense regulators & machines. to cure it, get the proper size T-Bar style hose clamps. Even cheap chinese ones. Put the T-Bar on the line first & then the worm drive. Put the hose on the fitting & set the T-bar. Then set the worm drive. T-Bar clamps never let go. Treat it like a tire, spray some soapy water or glass cleaner on the hose connections & regulator & find the leak. if it's the regulator itself unscrew it and put it back together. Sometimes you can get a better seal, other times its just bad. A lot of times the pressure gauge itself will leak.

If you ever suddenly feel tired or dizzy, cut the tank off & leave the area for awhile. Argon is heavier than air & will sink low. For us garage dwellers that means crack the car door a bit while you catch your breath.






what is it you're wanting to know about pulse? as an industry it is not used as much because it's relatively new and the machines that can do it are more expensive. Putting it out of reach of primary schools and into the better trade/secondary places. there is very little that actually calls for the two positive traits pulse welding gives you:
1) VERY high frequency pulse (200-300 per second) greatly increases puddle agitation, which will increase the strength of the weld at the granular level
2) less average heat input in extremely sensitive materials. (at which case the operation probably has the money to step up to replace tig with Plasma Arc Welding)

where in a relative sense it's used very little (both pulse with gtaw and gmaw), it's common in the hobby sector with new welders because it can be set to slow the welding speed down and on the surface to the un-trained eye "the dimes look prettier" because the peak current of the arc can level improper rod-dips into the puddle. On the internet, pulse is most seen by "all the newbies that make & sell turbo manifolds on the cheap". They use it because they don't know what they're doing. That's not a knock on anyone or pulse, just the most obvious & wide spread encounter most people will have with pulse.
<3


Take how large your bead should be and THAT is what your peak current should burn
Your average current should have a puddle size 1/3-2/3 as large. Any less than 1/3 of the puddle size and you may as well just be spot welding.
If you are having difficulty with something, & simply need to slow everything down you can set the pulse to be very low (a few times a second or less). If you want to go weld the 60' long titanium box frames that holds the 155mm cannon ammunition for the new BAE DDG-1000 frigates. Then you'd set it at 320pps so that you have the strongest x-ray quality weld you can possibly have. :)

[clintnz]

Originally Posted by Toysrme

No! you should NEVER be bleeding gas EVER. Very common problem with chiense regulators & machines. to cure it, get the proper size T-Bar style hose clamps.

It's just a very slight leak out of a vent hole on the bottom of the reg itself, will see if I can strip & check it otherwise will get another.

Originally Posted by Toysrme

what is it you're wanting to know about pulse?

We got a pulse machine as a friend who is a pro Tig man & does a big variety of work said it would make things easier on small & fiddly stuff, especially for a beginner. Which makes sense given the lower heat input & slower speed that it enables. As a n00b to welding Alu anything thinner than about 5mm seems to belong to the 'extremely sensitive material' category Plus the pulse version of this machine wasn't much more expensive than the one without.

I understand the principle of pulse & what the adjustments to to the output do, what I want is some ballpark guidelines for where to set them for best results on a given weld, so your advice on current levels is just what I need. I was bracketing the recommended amperage for the weld but it sounds like that should be the peak, with the base at a lower level & go a bit slower. How about the pulse width setting?

Cheers
Clint

[NitroAcres]

Do yourself a favor, turn the Pulse OFF, untill you get a good handle on welding without it, for a welder just starting out it just adds to the frustration level.

Work on puddle control, speed and feeding the wire FIRST...get that down, then after that start playing with the pulser.

JMO...YMMV..

[Toysrme]

exactly clint :) like i said pulse is generally used for super critical welding where you need really fasts pulses to make it stronger and really slow pulse to help newbies (that includes CNC machines!). a slow pulse rate it slows everything down while visually hiding inconsistencies in filler application :)
i can tell you what the controls do, and give you theory behind deciding for yourself. i can't outright tell you what to set the pulse too. if i crack open an AWS or ASME and start firing off exact processes it's not going to be easy for you b/c they're designed for experienced people doing production work. plus im not there to see you live

im sure you've figured out pulse width sets the bias for how long the machine stays on average power and peak power. normally it's the % of peak time, IDK on that chinese machine.
here's the thing... welding is all about the AVERAGE amount of heat you are dumping into the work. always think of it that way. without ever touching the actual amperage control, you can change the heat into the workpiece with a half dozen other changes you can make. unless you want to talk specifics 200 amps for 1/16th of a second is the same total heat dumped in as 100 amps for 1/8th of a second.

MOST of the time, people set the pulse width to 40-60% in industry.
if you really want to be able to see & control everything, slow the pulse rate down REAL low. a single digit number of pulses per second. like. 4-8 per second. set the heats like i said earlier (the peak needs to make the puddle your target bead width, average needs to set the puddle 1/3-2/3 that size, whatever is comfortable for the weld you're doing!).


if you want to make it super easy, lower the pulse width to 25% or 50% and raise the peak amperage a little bit to compensate. The arc will be little, ZIP you get a dime, the dime cools, ZIP you get another dime repeate.
pulse width will somewhat act just like setting peak power, if you need a little more burn in cut the pulse width up. many less advanced welders without a specific DIG adjustment are programmed to change how much the arc digs with the pulse width. i doubt chinese welders do that. they've always appeard to just be simple analog control/timer circuits controlling FET's when ive seen them.

as you can see, the reason you don't do this in an industry is because it can be SO SLOW! time is money (in both time, and shielding gas, power).








setting a really slow pulse is fine for learning or something beyond your mental/physical abilities and the welder's ability to run a stable low arc. just uses a ton of gas & takes forever. if it helps you to learn, sure set the pulse rate to 4 pulses per second and concentrate on keeping that torch held correctly & at the correct position for the weld. just a little more timing on your feeding your filler.

[ER70S-2]

Originally Posted by clintnz

..........it would make things easier on small & fiddly stuff, especially for a beginner.

Self taught hobby guy stuff: alum gets stupid hot really fast. I tack welded all 4 corners, on both sides of this patch (8 tacks). I didn't wait long enough for the piece to cool before doing this weld (on the right). You can see how it almost 'fell out the bottom'. The plug on the end is where I had to fill the sink at the end of the weld. (hook up the pedal, it's why TIG is so cool. If I had been watching anything besides the puddle, I'd have seen the entire bead sinking.) Whenever possible, use something behind the weld to support the alum. Once hot, it will fall out, just like liquid mercury. Use lots of heat sink and don't continue welding until you can touch the alum. I'm not posting this pic because I'm proud of it. Also note the fresh clean, stainless brushed, base metal. (actually, this pic was brushed again after the weld)



Here you can see lots of heat sink and an alum backer (sticking out on the right). If I'm welding thinner alum, I'll use a steel backing so I don't weld it to my piece. Steel is a poor choice and may cause contamination, IIRC copper is a better choice. You can also see the oxide cleaning zone halo around the bead, in this case I could turn up my balance (more penetration), the cleaning zone is wider than necessary (but you should be able to see it). This would put more heat in the weld.

Originally Posted by clintnz

As a n00b to welding Alu anything thinner than about 5mm seems to belong to the 'extremely sensitive material' category

The material above is 3mm (.125") Note: the shorter the arc length the better. I try to keep mine under 1/8", but still dip the tungsten into the puddle frequently.

Originally Posted by clintnz

I understand the principle of pulse & what the adjustments to to the output do, what I want is some ballpark guidelines for where to set them for best results on a given weld, so your advice on current levels is just what I need. I was bracketing the recommended amperage for the weld but it sounds like that should be the peak, with the base at a lower level & go a bit slower. How about the pulse width setting?

Cheers
Clint

Originally Posted by NitroAcres

Do yourself a favor, turn the Pulse OFF, untill you get a good handle on welding without it, for a welder just starting out it just adds to the frustration level.

Work on puddle control, speed and feeding the wire FIRST...get that down, then after that start playing with the pulser.

JMO...YMMV..

As NitroAcres said, screw the pulse, learn how to weld first. There are more than enough complications without trying to figure pulse on top of it all. My squarewave welder is older and doesn't have pulse.

[clintnz]

Thanks for the tips guys. I did have another try with the pulse at the suggested settings but it wasn't helping so took the hint & left it off. I had another good session last night until I had converted almost every flat piece of 3mm alu in the shop into a melted mess Some of the messes did start to look a little more like welds however:



ER70S-2's point about a steel backing causing contamination is a good one, I have been doing these flat on my bench & I think that's probably why the welds still look a bit dirty despite the stock being cleaned up well. When I tried a corner weld held up in the air it was much cleaner.

Cheers
Clint

[Toysrme]

you're welding a position that is a full pen with an exposed back. you really shouldn't have to result to shielding the back side but you can if you must. what you worry about is oxidation on the back side on larger welds. typically you avoid that with an aluminum backing/fusing plate and you simply burn in to that.