Subject: TIG, need help

From: [email-masked]
Date: 20 Sep 1996 13:48:35 GMT

Howdy folks,

Need some advice...

I'm in the market for a TIG setup. I currently have an AC welder that I'd like
to add a TIG torch to. I've looked through the MSC and Graingers cats'.

They both sell a house-brand TIG Torch Kit that is inexpensive ($131), but
I'm leery about that path. I'm actually thinking that the Genuine-Heliarc sets
might be a better buy. (Graingers is cheaper than MSC!).

I'm leaning toward getting the HW-17R torch ($71), and the Victor AF150-580
($57), flowgauge regulator. This seems to be quite a bit cheaper than getting
the whole kit from Heliarc ($265). I'll probably also need to get some electrodes
and collets...

(The HW-17R is a 150A 50%duty cycle torch. The AF150 is adjustable
>from  8-25ASCFH for Argon, Argon/CO2).

My plans are to use it for welding small pieces (1/8) mild steel, build-up
work on low carbon and stainless (316) and whatever else may be found
needed to do. Oh, and automotive body panels/floor pans.

My AC welder goes from 40 to 230 amps.

I'm not real versed on what I need, but I'm sure someone here can help.

1) What is required to convert my AC welder to DC. Is it just
a full wave bridge? or is there some inductors/capacitors involved
also? 

2) Would it be worth it to have a DC welder for TIG use?

3) How important is a high frequency arc stabilizer?

4) What kind of current am I going to need to do the above
mentioned welding?

5) I'm leaning toward setting up for 1/16" electrodes and
adding as required. Would this be a good choice?

6) In my travels, it seems that 75% Argon/25% CO2 would
be the best all around gas. Any comments?

7) And last but not least, anything to add?

Thanks in advance,

Bob

[email-masked]

P.S. To the guy thinking of the gatling gun, go for it. I'm waiting
for when I retire to make mine (no time now).

--

---

From: Bill Cottrell <"[email-masked]"@worldnet.att.net>
Date: Fri, 20 Sep 1996 07:51:28 -0700

[email-masked] wrote:
> --I have TIG welded pressure vessels (X-ray work) for over 30 years now, 
and don't profess to know it all by any means, but I don't think you 
want to use AC current on a TIG unless it is on aluminum, and then you 
would need a high frequency unit with it. For carbon, and stainless 
steels use DC current, no high freq (unless you want it for start only, 
and normal scratch start should work for you and be cheaper), and my 
personal reccomendation would be for 3/32" tungsten. CK (Conley & 
Kleppen) make excellent tig torches you might look at but any brand 
should do what you anticipate. -- Bill

---

From: [email-masked] (Peter Wiley)
Date: Fri, 27 Sep 1996 12:13:50 GMT

In article <[email-masked]> [email-masked] writes:

[snip]

>My AC welder goes from 40 to 230 amps.

For real delicate work, that may not go low enough for fine TIG work.

>a full wave bridge? or is there some inductors/capacitors involved

I bought a commercial AC-DC converter made by a welding company. Plugged
it onto my stick welder and it worked. 

>2) Would it be worth it to have a DC welder for TIG use?

Depends on if you can get one cheap enough; I'd say no.

>3) How important is a high frequency arc stabilizer?

IMHO, very important for steel to avoid electrode contamination from
scratch starts. Essential for aluminium but you need ACHF anyway. I've
done scratch starts on a piece of clean copper next to where I'm going to
weld and this reduces contamination a lot. Still a pain, though.

>4) What kind of current am I going to need to do the above

I'd say you're OK with your stick welder. Mine goes to 250A at 60% duty
cycle. Too much heat and you end up needing a water cooled torch. I've
found that my stick welder's amperage control is a bit coarse for TIG
work. YMMV.

>adding as required. Would this be a good choice?

That's what I use for my work. Sheet & fine work. Haven't bothered with
anything larger. Was playing with some 5mm plate tonight and I can run a
good bead on that at 100A.

>be the best all around gas. Any comments?

I use straight argon. Swap the bottle from MIG to TIG as needed. The CO2
mix is supposed to be better for steel, but I just prefer argon for the
(rare) occasions I want to weld aluminium. Don't want 2 bottles.

>7) And last but not least, anything to add?

Buy a TIG unit with HF. Better control and less hassle all round. OK, it
costs (which is why I didn't do it up front). I've just picked one up on
approval - been playing with it tonight, in fact - and if we can come to a
satisfactory agreement, it's *mine, all mine!!* AC, DC+, DC- and HF, 6A to
180A. I always wanted one of these.

Then I'll sell or (preferably) trade the AC-DC unit which has served me well.
(I'm not looking for a buyer here, though; I'm in Australia).

Best of luck.

Peter Wiley