High Frequency arc Stabilizer

Somewhere in the bowels of the shop, there is a Hughes Aircraft High Frequency unit that I picked up with the intention of setting up my old Miller 225A Thunderbolt AC welder. Plugs into 110V power and then the leads to the welder go through it, but that never came to happen and have since upgraded that machine to a dedicated TIG machine, a Miller Synchowave 200.

Tried the Miller Dynasty 300 at night school, that is one sweeeeeet machine!

Oh well, the HF unit is here and available if anybody wants to make an offer on it.

Walter
 
I had a HF for a short while. A buddy of mine and I tried to hook it to an old buzz box and managed to blow all the ground faults in the nearby kitchen. Gave it away and found a bargain, an old Airco TIG welder with the needed stuff built in.

Benny
In middle Tennessee, USA
 
About 7 or 8 years ago I had that identical Century HF start unit. I retrofitted my old Montgomery Ward AC/DC stick unit with one of these kits: http://www.tigdepot.net/products2.php?categoryID=67

That worked good enough to get me hooked, and from there I moved on to a Miller Syncrowave 300, which was a monster, and now I have a Miller Tigrunner 250.

Bottom line, from my perspective, is that the unit gave good performance given what it actually did. I had no foot pedal current control, but sometimes you make do with what you have.

I ended up selling it on eBay for $120 or so....
 
I finally got around to trying the HF function last weekend, without hooking up to a welder. I hadn't even done that much until now. Nice to see it arc at about 3/16". Now I need to make a couple of adapters to connect the torch to the HF output.

I'll try it with my little AC welder first, then the inverter. I'll run it through the current detector and set it up for Off, Startup and Continuous. After I get all that going, it will be hard not to go hunting for a bigger AC welder. Proof that winter is here.
 
Hawkeye, I have a straight sine wave machine and the HF is set to continous when I am welding aluminum. It's a miller Econotig I got back around 2006 and it is old tech at best. I doesn't have much in the way of bells or whistles but I can work pretty consistently with 3/16 and push ot for 1/4 with a little preheat and luck. Thicker stuff I use my Miller 210 Mig with a 3035 spool gun and call it good. So sine wave just needs the HF to keep the arc going when the wave is passing through the zero voltage section of the wave. Works great and is tough as nails due to being transformer technology. Have a great day
Bob
 
Thanks, Bob. That's pretty much what I was thinking. Play around with thin aluminum, just enough to see if I'm getting anywhere. Then it's pretty easy to pick up an old tombstone or something cheap to go thicker. My TIG torch is only rated for 125 amps anyway, so I'll do some learning before I try to move up.
 
Hawkeye. I would avoid very thin Alli as a learning or test plate. It is actually more difficult to control the puddle and burn through especially if you dont have a foot pedal. I recomend starting to practice on around 1/8 material, that will give you time to see and react to the puddle before it sags and falls through. A good starting amperage is generally 1 amp per .001 material thickness and keep your material meticously clean including your filler rods. Miller has a great TIG book, about 14 chapters in all that you can download for free from the miller electric site. Well worth the read if you have a little spare time. Good luck and let us know how you did.
Bob
 
Mike

The Miller TIG Handbook is a great resource.

http://www.millerwelds.com/resources/TIGhandbook/

Having just gone through "welding upgrade classes" I had that, the Modern Welding Textbook and any of the the info from Lincoln I could download plus the handouts from the instructor to compare. Miller was the most comprehensive, Lincoln was more about Miller bashing and why Lincoln is better than MIller.

Definitely start with 1/8" plate. Start by puddling. There is a fine line between penetration and plop! so watch your puddle closely. I found that I was getting really nice beads, but that my penetration was not quite deep enough, if you watch the puddle, you will see it start to slump and flatten out when you get proper penetration. On flat plate, you do not want to see any protrusion through the back of the plate.

The trickiest joint that I found was the butt joint, again I got really good beads, but only was getting about 50% penetration on 1/8" plate until I caught onto the puddle. If you hold the torch there just a bit longer, you can actually see the puddle start to flatten out, at that point dip in your filler rod to cool the puddle and advance your torch a little bit to get the next point. You should have full penetration and actually have a small bump on the bottom of the plate. Be careful as you move along the plate as the whole plate is heating up, the slump point gets quicker. Oh and only takes a split second after the slump point to get to the "plop" point when the whole mess just falls onto the floor.

Lap joints, Tee joints and corner joints are fairly easy to control.

Aluminium can not be welded without a filler rod! Unlike steel where you can melt the two together (autogenous) and get a really nice weld without filler, not so with Aluminium. Also rod choice is fairly important. ER5356 is the one that will be used for most of your welding on the common alloys like 6061-T6 or 7075T-53. The other rod, and the one that was available at the local welding shop was ER4043. this is good for 2014-T6 and 6061-T4. I found this puzzling as I have never run into 6061-T4, only the T6 temper is around. OH and if you plan on Anodizing the aluminium after welding, then ER5356 is the rod that has to be used.

If you get into TIG welding on steel, the filler rod used for oxy-acetylene welding is different than the one used for TIG.

Walter
 
Oh forgot to mention, Methyl Hydrate was the solution of choice at the school for cleaning rods and Aluminium before welding. Any rods not used withing 30 minutes had to be recleaned.

When I worked at a fabricating plant as a young pup, (we manufactured vacuum cleaners for fish) there was a lot of Aluminium welding and all the castings and weldments were tacked together then soaked in this huge vat of "acid" before going to "Missy Tiggy" to be welded up.

Walter
 
All good advice. The problem at this point is that my AC supply is just a little 70 amp unit. I'll be able to get a bit of technique going, but I won't try to weld anything I'm going to use. Once I see that I'm starting to get it, I'll hunt up a bigger transformer.

I do have a supply of TIG rods, but no aluminum yet, other than a roll of aly MIG wire. Thanks for the tips. I hadn't heard about the wood alcohol for cleaning. I've got lots of that. Will Scotchbright work for pre-cleaning?

I finally got a couple of adapters turned today to plug the torch into the HF unit. I'll pick up the last connector I need tomorrow and maybe try it out in the afternoon. Hope I don't forget to turn on the argon. :huh:

Thanks for the expertise.
 
You must log in or register to reply here.
Back
Top