Technical Difficulties from on Top of the Mountain
2006-02-06
  Accumulating a few things here and there (a novice's inventory of welders)
Looking back over last year, counting up stuff for taxes, I noticed that I had bought a few welders. Then I checked again, and realized I had bought a lot of welders. Like 10. You may be thinking, "why on earth does he need 10 welders." Well, I don't. But here is what I was thinking at the time.

Esab
Heliarc 160i
This was the first welder I bought back when I was rather poor but still wanted to get a welder. I had been buying up TIG part lots and so had already amassed quite a lot of torches, collets, tungsten, hoses, lava cups, etc. I figured it was time to get a machine I could use. I had borrowed a Maxstar from the welding shop before, but wanted high frequency start and a gas solenoid (so I didn't have to turn the gas on before welding).

Unfortunately I didn't have enough money for a working unit, so this item was purchased in non-working condition. But it came with schematics so I figured, "how hard could it be to fix it." Turns out that was not the right question, the right question should have been, "when am I going to have time to fix it." The answer so far? Not any time soon.

Trivia: This is actually a european unit which will run on 240V or 400V. At 400V it will put out 200amps.

HTP
Invertig 201

Shortly after buying the other broken welder, the startup I was working for got some funding; and because I am a cynical old crudgemudgion, I got a large check. A very large check. (How large? Well part of it I used to buy a highlander.) Another part of it I used to buy this and a big MIG machine.

This thing has all the bells and whistles. 200A power, AC/DC, pulsing, wave balance control, HF start, blah blah blah. The interface is a little clunky to use, but it welds just fine. (Better then me, that's for sure.) It is also a european import from Stel, though its relabeled from the original (also imported to England by Murex).

Miller
Maxstar 140
2 x STL
2 x STH

While the HTP could do anything and everything, it wasn't a very mobile machine. Kind of like the ancient luggable computers from Kaypro, and compaq; packed up in a suitcase, resembling a portable sewing machine (back when they were made from cast iron). Yes you can get a 40 pound machine into the back of your car, but you're not likely to want to do it very often. So when I noticed that you could pick up a Maxstar for less than $500 from time to time, I suggested that the school should get one (or two, or three, or however many I could find).

I started out geting one STL for the school (with a nice case), then I saw a STH machine with a finger tip remote, so I decided to get that for myself. Then another 140 showed up that nobody seemed to want, so I got that as well, and then recently there was another one languishing around for $410, so I decided what the heck. So we currently have three at the school, and the one I was going to keep is now at my dad's house. That's because, I then picked up a 150 ...

Still, these are brilliant little machines, and with 240V sources, put out full power for whatever you want to do. They are amazingly quiet, and produce a very stable arc (unlike the older transformer based machines). At 110V they're limited to 90 amps, so I wouldn't try to stickweld that way, but for sheet metal work where you only need 40-60 amps, its more than adequit. Lift arc starting takes a little getting used to (you touch the metal, then lift off), but actually allows you to place the electrode exactly before putting down your visor (like you would do with MIG), so it works out pretty good.

Miller
Maxstar 150
STL

Right after I had picked up a 140 STH for myself, this unit showed up online in a case with a remote, for a price I couldn't refuse. What's better about it? Come on, that's easy: 150 is 10 bigger than 140. Actually, it has a number of improvements over the previsous model. For one it can drive TIG at full power even using 110V assuming the plug doesn't melt. It also has a gas solenoid, so it turns on and off the argon for you automatically (a definite help for me). Otherwise its the same profile and weight, and comes in a nice carrying case like the 140.

The STH has even more bells and whisles, including high frequence start, and pulsing. The HF start would be cool. The pulsing I could probably live without. Unless I'm willing to practise a lot more, I think turning down the power to 10 amps for something really thin is a lot easier then trying to get the pulsing settings worked out for some particular weld. Maybe its useful for stainless, so far all I've managed to do with stainless is create a tortured warped mess.

Anyways, this is my new favorite on-the-go machine. Now if only my argon tank didn't weigh so much.

Chicago Electric
WSM 130A

Now TIG machines are expensive, more so than any other kind of machine. For $200 I can pick up an acetylene torch kit, or a used MIG welder, or even a buzz box (AC stick). But for TIG you need to spend at least $500 for anything useful. Unfortunately there are a couple companies out there claiming you can buy something for less and still TIG weld. This unit is one of those. Harbor Freight will sell you this setup for $200 (+shipping) and you get what you pay for (or less).

The machine does 130 amps TIG on 240V (and 90 amps stick, I don't know why they even bother with this). This is the same power you can get out of the Maxstar with 110V. But it gets worse. The duty cycle at 130 is 15%. That's 90 seconds of welding, then take a 10 minute break. I'm not sure it can even handle doing a eight inch seem weld without overheating. Still if you're only aspirations are to melt some sheet metal screws and fix the crack in shovel blade, this might be up to the job.

So why did I get it? Well, I thought a used one for $120 would be useful for people to try it out in the shop and discover just how lame a machine it is. At least if they decided to still get it, they'd know what they were in for.

Miller
XMT 300
CC

While 200 amps is fine and all. Sometimes you need a little more power. And sometimes you just want to get crazy. For a few dollars more, this beat up, patched together, inverter-of-doom was willing to put out 375 amps, and was loaded with all the TIG extras like a solenoid and HF start. Unfortunately all the power is only for those studly enough to have three phase power. The machine will run on single phase, but is only rated at 225A in that mode. So unless I can talk the power company into running three phase to my garage (or I pickup a used 20HP rotary phase converter online), I might as well keep it at the shop.

The nice thing about power is the higher the voltage, the lower the current. So while it would try and suck 60A out of my wall socket in the garage, it only needs 20A to run at 480/3Ø. That means I can use inexpensive 12/4 to make an extension cord for it and be able to wheel it around anywhere in the shop or out into the parking lot. Now I just have to figure out how to get power for the water cooler, and I can run a WP18 water cooled 350A TIG torch with it too.

Miller
XMT 304
CC/CV

Stick welding with quarter inch rod is fun and all, but if you've gone to all the trouble to regulate this much power, wouldn't it make sense to be able to switch over to holding the voltage steady so you could wire feed with it? CC/CV is the answer (constant current/constant voltage), and when this machine showed up in Vegas, I sent my friend Tom over with cash in hand to pick it up. There it sat for a couple of weeks until I found someone who had a friend that was coming to visit from Vegas, and we hooked this machine up this weekend.

It burns like a champ, has a nice digital display, and more modes than even I know what to do with. Unfortunately its just a power source. MIG welding requires a wire feeder, and there's no extra help for TIG. Sure you can scratch start or lift arc it, but I'd like the HF & gas control like 300 CC. Miller is happy to sell you an add on, but they want several hundred just for that, and then its only rated at 250 amps. At least the wire feeders I've seen recently are rated 600 amps 100% duty cycle. Gads.

So that was my plan this year, at least for TIG. (I'll save my MIG machine acquisitions for another story) Now I have more welders in my own inventory that the school has in their entire shop. Course I'm happy to keep most of them over at the school anyways. I've got keys, and I don't have to pay the electric bill. Mr Hess just shakes his head and wonders what I'll think up next.

 
Comments:
I would appreciate some advice on finding a TIG welder that works instead of the one I have now. I will mainly be welding steel and stainless steel of small gauge. I made the mistake of buying one of those Chicago Electric TIG's and it is utter crap for TIG welding. It doesn't control the arc and current worth a darn. Even on the lowest setting I was burning holes in 16 ga steel. Dorson.Foster(at)gmail.com
 
I got one of those things because you can hardly get a little tig torch and leads for that price, and if it sucked, I'd give it to my dad-in-law. I changed the crappy ground clamp to a nice Lenco first thing. I had the same problems burning holes in thin stuff and was VERY frustrated with it, then I noticed a quirk...

You touch the tungsten and it activates the gas preflow and about 0.5 seconds later, the voltage goes way up and stays that way for about 1.5 seconds. If you scratch an arc during this time, it will start at about 80 amps!

Touch and back off quickly, count 1 Mississippi-2Mississippi and scratch your arc. It will hold the low current setting very steadily. If you stick the tungsten or have trouble starting the arc, it wants to kick up to higher open circuit voltage and burn at 80 amps for 2 seconds before dropping to your setting. If it tries to burn through, let the postflow go off before trying again.

After I discovered this, I was able to butt weld razorblades with this thing. Don't get me wrong, it's in a class of its own (ie cheapo), but it will do enough things to make it worth the money. Now above 70 amps, it seems unable to steadily control current... not much of an issue with tig but a BIG issue with stick. It's limited to 3/32 7018 rods, but does an excellent job with them. 1/8 rods start to show defects from unstable current (ie unstable arc). It really screams (i mean audibly, not figuratively) above 70 amps, like it's way overloaded. I will be looking at the output waveforms with a scope soon. Also going to mod the panel to replace the knob with leads to a footpedal.
 
Any suggestions for how to wire the foot pedal? (And what foot pedal to try?)

Thanks!
 
I discovered the Harbor Freight 130A TIG, #91811 has issues with noisey power line. I turned the power on the unit which was also sharing a Lincoln TIG250/250 while it was doing A/C TIG welding. The little TIG was chattering away and messed up the electronics. It won't start the arc, it turns on the gas when you do the lift start and won't turn the gas off. So basically there is no protection such as line noise filter, etc.
 
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