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Tig Question ???

vorra65

Well-Known Member
I'm thinking about buying a Tig machine. I'd like to be able to do chromoly and some aluminium fab work. What should I look for, in the machine? What are the most important feature's I should look for? There's a ton of machine's out there, and I could use some sound advice. I don't want to buy, and then regret not spending a little extra. Also, what should I expect to spend. Keep in mind, it doesn't need to be a production machine. Any help will be greatly appreciated.
 

Kritter

Krittro Campbell
I think all tigs will do almost any metal with the right setup. You need to have AC for aluminum and a high start frequency i think its called to initilaize the arc and keep from contaminating the weld from contact. I was looking at some pretty nice ones for home and they were about 1500 ready to go. I checked them out at the Expo... check out Grainger or McMaster Car because they seem to have some good deals or your local weld shop.

If you wanted a steak you shouldn't have went to McDonald's!
 

rdc

- users no longer part of the rdc family -
Lincoln 225 is a good machine. Lincoln also makes a smaller one (175), but if you got the cash, go with the 225. Check into a good torch for it, like tweco. Also, spring for the water cooler. The minimum tungsten to use would be the red one (they are painted on the flat end). Anything less will give you trouble on aluminum. Get some good gloves and a good hood. I like the small Huntsman. It is more face sheild than hood, but it's much lighter. Get a box of clear lenses. Put one over and ond one under the tinted lens. When you pock up the clear lens, throw it out and replace it. It's cheaper than the tinted lens. If you weld at night, go with a darker lens, please. Save yer eyeballs. Don't wear a white shirt either.

This is my humble opinion. Keep asking around. I ain't no expert.
 

rdc

- users no longer part of the rdc family -
If you want to do ferrous and non-ferrous TIG welding you will need a machine that is AC/DC and has a hi-freq. unit. AC is for alum. and DC is for the carbon steels(chromoly). Look at the Miller Synchrowave 250, it is all the machine you will ever need.
Richard
 

ntsqd

Well-Known Member
In addition to what's already been said, a machine that allows you to adjust the AC dwell in Pos. and Neg. will be a bonus. When the current flow into the electrode it has a cleaning action on the work and when it flows from the electrode it penetrates more. Depending on what you're welding, new 1/4" plate or a nasty, broken Sprint Car Cylinder Head, That adjustment can really pay off. With new metal you can adjust for mostly penetration which will also reduce the width of the 'abraded' area next to the bead so a fresh weld will be very cosmetic.
Also, generally a green tungsten (pure tungsten) is used on middle thickness (~1/8" - ~1") aluminum. When you get above or below that approximate range, or you're doing something special, then you might use a red tungsten (2% Thoriated). It's not that you can't weld aluminum with AC and a red tungsten, it's just easier to start out with a green. Wait until you're fairly proficient with ferrous metals b4 trying aluminum. I've met one person who started on aluminum and had an easy time learning to weld it, but had trouble with steel. Most people are the other way around. My general philosphy with aluminum is "Stuff rod in and GO !!" You can't hang around in one place very long like you can with steel.
Old school has you striking a reverse polarity arc on something like a slab of copper with a green electrode to ball the tip prior to setting the machine AC and welding. I don't bother. The electrode will ball up reasonably fast. I just grind the end square and start welding. If it balls up too big and threatens to, or does drop into your puddle, you have too small of an electrode diameter for the current.
Red electrodes are commonly used on ferrous metals. On the thin stuff in particular you want to try to match the tungsten diameter to the metal thickness.
I wouldn't bother with R. Finch's "Performance Welding". I met the man and he knows a lot about welding (& about Corvairs too), unfortunately it doesn't come out in his book. If you want a book, find a real text book on the subject.
FWIW I find that stainless is the easiest to teach people on. Mild boils too easy and with the concentrated power of a TIG that is easy to do. Stainless is not only more forgiving of that, but it also wets out and flows easy and rewards with pretty beads fairly early. A little ego boost about then is a good thing.

Have any of the other TIG welders out there fiddled with the Yellow or Brown electrodes ? What are their uses/applications ?

TS

"Teach you all I know and you're still stupid"
-- Howdy Lee
 

BradM

Well-Known Member
Any tig that has AC/DC capability with both reverse and straight polarity will weld both Aluminum and steel. However, the limits of just any machine will show up when you try to weld very thin Aluminum or very thich Aluminum. I would suggest that you consider a tig with square wave technology. You can find an old one use or look at the Miller syncrowave series or the Miller square wave series or equivalent. Also, the larger machines like the Syncrowave 250 or the Squarewave 255 come with a water cooled torch which is smaller and more versatile. The smaller version like the Sincrowave 175 has an air cooled torch. If you were to buy one new and then later add the water cooled torch and a radiator, you will be almost at the price of a larger machine like the 250.

You may not plan to do production work but you will never regret buying a machine that is more than adequate for your needs. Besides, if you take care of it, a good machine will hold it's resale value. I highly suggest you look for a good deal on a used machine. Also, talk to a few local welding shops. They may know of someone who wants to sell a very nice machine at a reasonable cost because they want to step up to a bigger machine.



"The only source of knowledge is experience." - Albert Einstein
 

PATCO

Well-Known Member
I was thinking about buying the small miller or lincoln.
Is the air cooled torch that bad? I will be doing light fab
in the garage.(bumpers, shockhoops, etc.) Has anyone
used either machine?

PATCO
 

BradM

Well-Known Member
I have not used one but from what I understand they will over heat if used continuously. You may need to let it cool at times. Also, the air cooled torches are physically larger and may be more cumbersome in tight areas. I did not mean to infer that they were inadequate but rather inferior.



"The only source of knowledge is experience." - Albert Einstein
 

mike_hinson

Well-Known Member
I use an old 150 AMP Miller machine that I bought new 15 years ago. Air cooled is OK for light fab work. That is what I use. Make sure that the machine you acquire has the hookup for a foot pedal. If you don't have one to start out with, you may want to add one at a later date.
 

Kritter

Krittro Campbell
Just check what the duty cycle is for the welder and I am sure they incporporate a safety factor for an aircooled torch.

Kris

If you wanted a steak you shouldn't have went to McDonald's!
 

Jimmy8

Well-Known Member
You can get TIG machines with radiators on top. Thats what ours has, and we have never had a problem with it over heating.
 

Kritter

Krittro Campbell
The radiators for the watercooled torch not the machine I thought?

If you wanted a steak you shouldn't have went to McDonald's!
 

FABRICATOR

Well-Known Member
The "radiator" is a cooling unit for the torch. Air cooled torches get the job done and are inexpensive. They are also heavier, bulkier, and do get hot. A good water cooled TIG torch is about $150.00. A new cooling unit starts at about $600 dollars. There are used ones out there for around $200 to $300. Or you can tap into your plumbing somewhere and let the water run through the torch and out to your bushes or into an old Sparkletts bottle. There is nothing wrong with this method other than forgetting to turn the water on and/or not watching the drain bottle overflowing and flooding out your garage. (been there, done that) A cooler usually goes on and off with the welding unit. Buy the best you can.

<font color=orange>The best ideas are the ones that look obvious to the casual observer.</font color=orange>
 

ntsqd

Well-Known Member
I've used an air cooled torch on a 300 amp machine. They get hot pretty fast welding thick aluminum. Air cooled is kind of a misnomer. They are cooled by the shield gas, of which you only want to flow so much for $$$ reasons.
We used to use a 5 gallon paint bucket full of coolant pumped by some ancient diaphram pump at one of my past employers. Still melted the coolant tube to the torch fixing a Sprint Car head and got a nice burn across my forearm. I know people who use the total loss garden hose trick, works well.

TS

"Teach you all I know and you're still stupid"
-- Howdy Lee
 

Kritter

Krittro Campbell
I know at school we have a big TIG machine and one of the professors got bent when we used tap water. I dont know why, but he made us replace it with DI water.

Kris

If you wanted a steak you shouldn't have went to McDonald's!
 

rdc

- users no longer part of the rdc family -
The "radiator" is a water cooler. I thought you said you can "tig weld pretty damn good". Is your water cooler an add-on or did it come built in the machine?? What's the difference?? Does Miller or Lincoln make their own water coolers?? What do you run in your water cooler?? How many inches of weld can you push before your torch gets hot?? What torch are you using?? How long is the lead?? Does your torch get hot before your machine cycles out or vice-versa??

Thanks in advance for the information. SD
 

BradM

Well-Known Member
For the most accurate response to that question, go talk to the folks at a good welding supply shop.

"The only source of knowledge is experience." - Albert Einstein
 

vorra65

Well-Known Member
Thanks to everyone for the input. I bought a Miller SD180 Squarewave machine. It's a used machine in great shape, came with the bottle and a cart. I think I got a good deal, paid $1250.
 

Dylan

Well-Known Member
for my friends sincrowave 250 he built a cart that hade a flat 12 gallon tank that mounted under the machine with a circulation pump. 12 gallons is a large enough body of water that ulless you are are welding at high current for hours on end it does not show a significant temp difference. we sourced the same motor and pump that most of the purchased coolers use from granger and mcmaster carr. it is also wired into the machines aux.outlet to turn on with the machine. i have never noticed a difference between it and any other coolers i have used. the air cooled torches are very clunky, once you use a water cooled torch you will hate an air torch
 

rdc

- users no longer part of the rdc family -
That's a good buy. I would feel satisfied.
Good luck and enjoy.
 
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