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Travis Rankin 01-02-2006 03:27 PM

My DIY tig welder..
I thought I would share this with you guys as some of you may want to do it as well...

Its a full functioning DC tig welder with foot control and max output control on the machine.. it puts out 140 amps at 100% duty cycle.. soon to have a proper cover, pulse control and HF start.. eventually I may setup HFAC for aluminum, but otherwise good enough for now :)

crazy larry 01-02-2006 06:31 PM

wiring schematics please.??? how do you like it? do you feel that it gets enough penetration??? etc etc etc......

btw, :thumbup:

can we get some details on the car you have in your journal? what motor tranny ??? looks very interesting.

Rob Keller 01-02-2006 07:35 PM

Hey travis

Ok I worked for a welder that had this portable unit that had a small gas motor on it one day I had to pull off the cover and was shocked that it had a GM LOOKING alt making all that juice!!

what is the difference in the units and could that be mounted under the hood of a work truck??

that is way cool i been wondering these things for years


SR66 :thumbup:

Travis Rankin 01-02-2006 07:53 PM

There is not much difference.

I first learned this setting it up on my truck..

It is all very simple..
Alternators work buy creating a spinning magnetic field, wich induces the current in the stator, and from that you get output power

the magnet field is made by putting voltage through the field coil.

no juice at the field coil = no power
full 12v at the field coil = max power
and it varies in between

So by this the vehicle regulator works by regulating the field coil current.
There is a sample wire that sences the battery voltage, and by that it knows how much to give the feild coil..

So a quick and dirty alternator welder.. you just put full 12v into the field coil and you get full power.. Bam! Welding current

Its a little more complicated to make it reliable and user friendly...

More to come ;)

Travis Rankin 01-02-2006 08:01 PM

its got lots of umph.. this is the edge of my 1/2" steel table no filler..
sorry for the bad pics , having some issues with my camera :P

crazy larry 01-02-2006 09:11 PM


Originally Posted by Travis Rankin
Its a little more complicated to make it reliable and user friendly...

More to come ;)

I'd like reliable and user friendly.

Travis Rankin 01-02-2006 09:56 PM

Ok so next up...

Alternator modifications:

I like and chose the Delco cs144, there is lots around, parts are cheap and you dont have to solder anything(original stuff). You can use almost any alternator. The theory is the same, but I am only dealing with this alt.

Ive always used the 140amp version, the more power the better :P

Anyway, there is a rectifier inside that changes the current from high frequency three phace AC to high frequency DC. But the original rectifier lets the smoke out the second you try to weld through it. This is becuase it has avalanche diodes and I believe they are set up to blow if the volts get to high. Simply as a safety measure for your cars electronics.

You have to take the alt apart and replace the rectifier with a Transpo Part# dr51173 Rectifier. It works like a charm ;)

Also take out the regulator, and throw it in the garbage.
Next, Solder a wire to the terminal where the regulator was attached to the field coil brush. And run that wire outside of the case.
I drill a small hole, slip the wire through and JB weld it in so it doesnt move around. and put it all back together. You can clock the case around as well to move the post to the best spot.

and mount it on your engine/electric motor

Travis Rankin 01-02-2006 10:09 PM

now you have a power supply.

put 12V in the wire you just installed and you have welding current.

the easiest way to use this is to install it into a vehicle.

Go and buy a ford external regulator about $10

I can't remember the the letter designations right now but you run one wire to it that is turned on from the ignition key to power it.
On wire straight from the battery, so it can sense the battery voltage, and one to your new wire. that one runs it. On the regulator there is an extra terminal, you dont need it but you can use it to run the charge light in your dash.

once thats all hooked up you just hook the Batt. terminal to the battery. and now you have a very nice 140 amp 12v charging system for your vehicle.

Now all you have to do to weld is take the batt. wire off of the battery, and hook up your stinger....
!!!straight from the batt. terminal on the alt to the stinger, nowhere else!!!

and a negative clamp to the vehicle chassis.

Run the engine.

I hooked up a hand throttle by using a bicycle gear shifter to the throttle, in order to idle up and set the RPM. the faster the engine the more power you get. and that's how you set the heat. if you rev it up to about 3500 you can run angle grinders and brush motors.

What happens is the regulator thinks that the alt isn't charging (becuase the output isnt hooked up to the car 12v+), and it puts out max power to the field coil. I swear it is the best arc welder I've ever used, the HFDC is super smooth and burns nice and deep.

crazy larry 01-02-2006 10:23 PM

how many rpm/hp is the electric motor in your pics? I have an alternator, an electric motor, some 4 gage wire, and a strong desire for electrocution. :drool: could you get into more detail on the shop set up in the pics? I'd feel safer trying that than to risk burning up my truck.... have i stated yet, i'm a schnook?

Travis Rankin 01-02-2006 11:25 PM

the motor is 1750, geared almost 1:3 with pulleys

hook it up and let her fly its actually quite safe.

ill let you in on the control electronic tomorrow.. but you can get started with just full 12v from a car batt. to the field, it works good.

ChevyThunder 01-03-2006 02:23 AM

this is very awsome. I now too want to make one. I have a burnt out alternator in the garage (of all things the regulator blew). Old electric motors seem to go for cheap too. hmmmmmmmmmmmmmmmmmmmmmmmmmmm Do go on :D :thumbup:

cboy 01-03-2006 07:43 AM


My guess is you are going to get a HUGE response to this enticing post and project...along with dozens and dozens of questions. First off, thanks for sharing your brilliant shade tree engineering in this thread. And second, to save yourself a lot of time over the next few weeks responding to everybodys pursuit of details, might I suggest that you go a little overboard at this juncture with pictures, wirings schematics, and a detailed parts list. And as knowledgable about electronics as you might think we are...we're not (at least I'm not). So it would be tremendously helpful if you aimed the technical descriptions of what you've done here to the "novice" level. Sort of like an "Arc Welder for Dummies" book you might see at Amazon.Com. You will never go wrong by over simplifying your descriptions and having too many pictures. I can gurantee you that.

Once again, thanks in advance for starting the thread and sharing your handiwork.

oldred 01-03-2006 09:42 AM

Travis, Being the tinkerer I am I find this extremely interesting and I am sure a BUNCH of others will too so keep it coming! :thumbup: :thumbup:

Travis Rankin 01-03-2006 10:55 AM

I'll do my best to make it simple, so everyone can understand..

and Ill try to get as much free time as i can to do so.

so does everyone understand the jist of the alternator power supply..

lets try and get that part covered before i move on to the control electronics

matt167 01-03-2006 01:46 PM

I knew it was possible to stick weld with a car battery and a set of jumper cables, that seems like a neat idea until your the guy that the battery blows on, that is why I never tried that. I got an alternator and a motor, maby I'll try and make 1.

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