Subject: TIG welder plans

From: [email-masked]
Date: 29 Nov 1994 02:15:50 GMT

Has anyone come across instructions/plans to build a TIG welder?
Perhaps in Popular Mechanics? MIG welder conversions?

chris price [email-masked] (work address)

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From: [email-masked] (Gordon W J Sorensen)
Date: Tue, 29 Nov 1994 17:20:06 GMT

: Has anyone come across instructions/plans to build a TIG welder?
: Perhaps in Popular Mechanics? MIG welder conversions?

: chris price [email-masked] (work address)

Hi Chris,

I am not sure what you mean or intend when you say, "build a TIG welder".
Are referring to the power supply, the torch head itself or the whole thing?
Making the torch head would be fairly difficult as the environment that it
has to function in is rather severe.  I think you would be time and money
ahead to just buy the torch head, and gas regulator.

As for power supplies, just about any DC welder will suffice. I have
used a Miller Thunderbolt (I think that is the name of it) with a TIG
torch quite successfully.  It lacks the foot control and the electric 
solenoid switch for the inert gas shielding, but for occasional use it 
is more than satisfactory. With DC you are pretty much limited to ferrous 
materials.  Aluminum requires the high frequency AC component to keep the
oxides away from the welding puddle.

As for MIG welders, you need two major components to make that scheme 
work, a wire feeder, and a constant voltage power supply. (Most stick 
welders, Lincoln ARC and Miller buzz boxes are constant current supplies).

The wire feeder is perhaps the trickiest part as this component usually
determines how well the MIG welder performs.  At a local trade show, I
tried out a portable MIG welder. The wire feed mechanism was driven by
a variable speed cordless drill (which was supplied by the user, it 
wasn't part of the package).  As a power supply it used two 12 volt
deep cycle marine batteries. It actually worked fairly well although it
was a bit on the bulky and unhandy side (It took two hands to operate it).
Basically it used the drill to drive a set of rollers that fed the wire
through a nozzle. It used the small 1 pound spools of wire and would work
with solid or flux core wire (ie, gas or gasless shielding). 
To use it you held the drill in your right hand and the feed roller and
wire spool mechanism in the other. A cable went to one side of the batteries
and a ground to other side, (the batteries were in series).

Point the whole thing where you wanted to weld, flip your visor down and 
pull the trigger. As I said it worked okay and you could also weld aluminum 
with it also (you need wire and shielding gas). You control the amount of 
current, ie, heat by varying the speed of the drill. 

Two 12 volt batteries actually make a very good constant voltage supply.
You weld for a while and put the charger on them in between times. Not a 
high capacity high duty cycle set up, but good for the occasional 
garage home shop type. Two large batteries should let you weld 1/4 inch
stuff fairly easily, especially if you are using flux core wire.

Any way, I eventually opted to buy a portable MIG machine a LINCOLN ARC
SP-130T which I am quite pleased with. It was about $500 with a regulator,
and a 10 pound spool of solid wire. It was about $200 more for a cylinder 
of CO2 and Argon.  If I remember correctly they wanted about $200 for the
portable MIG machine, less batteries and drill motor.  

I guess what you choose is pretty much dependent on your situation, 
(finances and inclination). So go for whatever.   If you are
a real glutton for punishment, I can send you the secrets to converting
a car alternator into a ~120 amp DC welder. Add an 8 hp gasoline engine
and viola, you are in the portable welding business.

Happy burning

gordon s.

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From: [email-masked] (Joseph R. Landau)
Date: Thu, 01 Dec 1994 03:46:33 GMT

In article <[email-masked]>, Gordon W J Sorensen ([email-masked]) writes:
>..................... I can send you the secrets to converting

And you can have music to weld to :-)

Joe

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From: [email-masked] (Andy Dingley)
Date: Sun, 4 Dec 1994 12:06:42 +0000

In article <[email-masked]> [email-masked] "Gordon W J Sorensen" writes:

> At a local trade show, I tried out a portable MIG welder.

> It used the small 1 pound spools of wire

I'd echo your comments about reliable wire feed being the most important
feature of a "good" MIG.

In the UK, the wire reels are all much the same price, no matter what size
(especially if you buy S/H). It's thus a false economy to buy a small machine
that can only use small reels, as you'll find yourself paying more for the
wire than you did for the machine.

--
Andy Dingley                             [email-masked]

Remember children:  'M' is for Monoculture and for Microsoft.

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From: [email-masked] (Paul Amaranth)
Date: 5 Dec 1994 15:46:10 GMT

>I'd echo your comments about reliable wire feed being the most important

Ditto on that.  I bought one of those relatively inexpensive MIG welders
>from  Harbor Freight.  The transformer/choke/rectifiers were OK, but the
wire feed was very poor, particularly at the low speeds needed for thin
metal.  It did fine on 1/4 plate though.

I ended up building an entire wire feed unit for it with closed loop
electronic PWM motor control.  Works pretty well, but I'm probably going
to rebuild it this winter and make it a little more robust.  It's a little
flimsy to adequately handle wire speeds above 300 in/min for the heavier
wire (.035 or .040).  Does fine on sheet metal, though.

It costs money to make a good feed unit and that's where the cheap welders
cut corners.  On my unit, for example, the motor was run off of the
welding transformer using an open loop pwm controler.  That meant that
when you changed the welding voltage, you changed the wire speed.  Nothing
like having a calibrated dial you can depend on :-)

Oh yeah, the reason I had to rebuild everything, was that I put a Tweco
torch on it too and I needed to change the torch attachment point.  The
original torch was pretty crummy.

As usual, you either pay up front or you pay as you go, but it comes
to around the same amount in the end.

-- 
Paul Amaranth  Manager User Services - office: (810) 370 4541 (also voicemail)
               (e-mail)     [email-masked]    [Rochester, Michigan  USA]
   Mosaic page: http://www.acs.oakland.edu/links/amaranth/amaranth.html