Thread: ALTER POWER IN CAR WELDER

I stuffed around building one years ago, and it worked ok, but I didn't run anything off it - just used it as a welder. Basically it was a 65 amp alternator (that's the biggest I could lay my hands on at the time), but a bigger unit would work a bit better, hung off the other side of the motor.

All you really need to do is bypass the voltage regulator in it and bring the revs up until you get enough volts to strike an ark.

As I recall, at about 2800 RPM, I could get an open circuit voltage of about 130 volts, and I could weld 3mm mild steel well with a 1.5mm rod.

Crude, but effective. I never used it while I was out and about, but it served me for a year or so at home doing handyman sort of work until I bought a real welder.

I will insert links and info on ones Ive found (not the Battery ones)

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this one isnt quite car mounted......

Jon's Place/Jeep Page

Welcome to Jon's Jeep
Portable Welder Plans Page...


During the Christmas holidays, while I was visiting my parents, I got to reading the YJ FAQ (it has a lot of information in it relevant to CJ's as well).

The first question in the FAQ is regarding using the alternator in the Jeep as a welder. While I'm pretty sure this is possible, and I'm planning on doing it myself fairly soon, the answer given is not at all clear on exactly how it's done.

My dad recalled a photocopy of an old Mother Earth News article that described in detail how to build a portable DC arc welder using a car alternator, so he dug it up. We took an afternoon and built the welder, and it was very cool to actually weld using something we put together that quickly (and cheaply).


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The Welder Plans
Basically, what you need is the following:

car or truck alternator, preferably without a built-in voltage regulator (although you can use one with a built-in regulator, you have to bypass it)
motor or engine
car battery
platform to mount everything on
on/off switch
big diode
thermal overload switch
one or two 1.5 ohm 8 amp resistors (you may not need these if your motor is powerful enough - we needed them with a 1 HP electric motor)
a couple feet of #18 wire, and a couple feet of heavy (1/0) wire
old pair of jumper cables
bunch of connectors/stak-ons

For a platform, you could use an old lawnmower, and thus also be supplied with an engine and a place to mount the battery & alternator. We used a chunk of plywood, with a few pieces of angle-iron to mount everything to.

For the alternator, we used a regular 66 amp alternator, the kind with a built-in regulator. We took the regulator out, and bypassed it, grounding the brush it was connected to.


(go to link for picture)

Wired as above, you get a reverse-polarity DC welder, which is standard. To get a positive polarity welder, just switch the ground-clamp with the rod holder.
We used the jumper cables as our welding leads, and drilled a couple small holes in the end of one of the clamps to act as a simple rod holder. After we got it working, and laid our first bead, we "machined" a new custom rod holder using a chunk of 1/2" steel and a piece of pipe. Cut to shape, drill a few holes, tap some threads, weld it together, and you get a nice (cheap) rod holder.

I hope you find this useful. When I get my on-board welder project done (due to start in February, immediately following my on-board air project), I will provide full specifications and plans and pictures of what I have done.

...

build your own TIG welder... still not car based..

http://www.google.com.au/url'sa=t&rc...BPLHyaKyg3YvKQ

Originally Posted by Blknight.aus

hmmm....

and what would it take to liberate a copy of them from you?

I feel a project coming on.

If you are coming through Kilkivan pop in and take a look and see whats involved.

cheers guys but I was more interested in getting the mains power out of it.

heres a link to an older homemade car one...

http://www.vintageprojects.com/metal...oArcWelder.pdf

by the way, I enjoy checking through this site...
(vintage projects)

Originally Posted by Blknight.aus

cheers guys but I was more interested in getting the mains power out of it.

I like your style but unregulated high voltage high frequency messy DC is good for what exactly? Inverters are cheap enough. Or do you just like the dangerous stuff? How about a bunch of smoothing capacitors to add to the "pow" factor?

Anyways, a 24V alternator goosed up may be a faster path to 240V.

Wont work drills with variable speed on trigger.

because I have seen a mod done on an externally regulated alternator that lets it put out cleanish (enough for hand power tools and incandescent lighting) 240Vac, given it cant charge a battery at the same time but then it wouldnt need to fozzys diesel so comes with a governor thats pretty much set and forget for that kind of stuff.