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home made welder?


meancoyote

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anybody ever heard of making a welder from an alternator? a guy at work was talkin about it today and i am interested. looked on the internet and found a few places selling kits, but i may try and make one from junkyard parts maybe.


check out Burden Sales Surplus Center - Hydraulics, Engines, Electrical and More they have all sorts of stuff to build your own welder or anything else
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Popular Science Publishing Co. did their Amateur Craftsman's Encyclopedia in 1937 for guys with lots of spare time on their hands. In it is a piece with some instructions on how to make a welder out of an Model A engine-- no figures given on output, but article indicates maybe 200 amps. Piece assumes ammeter, voltmeter, field rheostat, current selector switch, terminal posts, resistance coil, resistance unit, and various wires and terminals" can be "ourchased all assembled and wired in its angle iron frame."

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Hi meancoyote. Yes, these work. But they are difficult to control. The standard voltage regulation scheme in an automobile alternator tends to keep the voltage constant. This is more appropriate for MIG welding. For stick/TIG welding, constant current is more suitable, so you have to replace the voltage regulator with a homebrew current control circuit. The Internet guru of alternator welders, Grant Stockly took his website down, but it had some great proven circuits for accomplishing this. Grant also did extensive experimentation and showed that motor-alternator combinations, since they operate at higher internal frequencies, would transfer more power at less weight. A typical automobile alternator has a lossy fan and undersized wire, so it is only about 50-60% efficient. One horsepower is 746 watts, and you need at least 1000 wats to make a useful welder. In that case, a 2 HP motor is a bare minimum, and Grant recommended 5 HP. Grant also had a table of more efficient alternators (esp. truck types) along with efficiency ratings. If you are serious, a better quality alternator will make life more pleasant.

Also, there is another gotcha to point out. Most inexpensive automobile alternators have diodes that avalanche at about 50V (foggy memory, maybe this is approximate). This is marginal for welding, especially stick welding. The higher quality ones, especially truck alternators, have higher voltage ratings, since some trucks run on 24 volt systems. Grant had a cool idea for a multiphase voltage doubler circuit to boost the voltage to meet the requirements for plasma cutting. It worked!

Give it a try, if you don't spend too much money. You should be able to get an arc out of it. I once made a homemade welder out of a junk microwave oven. It was a lot of work, and it would not hold a reliable arc. It was useless, even compared to the lowest end buzz box you can find on craigslist for about $100. Alternators are a better platform than microwave ovens.

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Hi Pam. Yes, this does work. Use two batteries in series, and roll a thin layer of damp newspaper around the coathanger to make ersatz 6010. I think it runs DCEP. I use my car's battery, along with a carbon rod from a cheap Everready cell, to weld my thermocouples. Make sure to wear flash goggles if you do this!

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Vintageprojects.com, I think has someting about that, I believe they used a 24 volt
alt. from a military truck or jeep, I have a stick, and 2 gasless wire welders. So I didn't look into it any farther. But goodluck on your project! would like to see pictures of your progress!

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  • 4 weeks later...

I learned about this idea many years ago in a bull session about neat stuff you can build out of junk. While I am a big advocate for home built stuff, I can't remember reading or hearing of anyone actually using one of these alternator based welders as their primary welder. They were nearly always built simply to prove a point. Yes, it can be done but the blood sweat and tears, not to mention monetary resources that would need to be spent to make it work well are even beyond my frugal tendencies. (ok I'm cheap;) ). I have one of Lincoln's AC "tombstone" welders that I bought nearly 30 years ago, and it is all the arc welder I have ever needed. It was $130.00 and I'm pretty sure they can still be bought at farm and home improvement stores for less than $200. With the proper rod and heat selection, it will weld anything from exhaust pipe, all the way up to heavy plate. It will weld 1/4" plate in one pass and anything heavier in multiple passes. In my 20 years as a professional welder I learned multiple passes are typically required on anything over a 5/16" fillet weld no mater what welder is used anyway. I don't remember AWS (American Welding Society) rules verbatim but I believe anything requiring a 3/8" fillet required multiple passes due to weaker grain structure in larger welds. NO homemade welder is going to efficiently provide that kind of capability.

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i use a miller trailblazer 302d at work, but ive never had anything better then a 110 v wire feed at home, im ready to start doing some bigger projects at home. will the ac welder run 7018 and 7024? the reason i want the ac/dc is so i can run 7018, but the ac is alot cheaper.

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It is my understanding that there is a 7018 rod available that is rated for AC. Not sure who makes it. (Lincoln Electric?) Check with you local welding supply. The other option is 7014. Very nice to weld with but mostly for flat work. For heavier stuff, beveling or chamfering of the parent metals is required as I don't think it has quite the penetrating qualities as 7018.

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Buying a Miller Thunderbolt (AC buzzbox) off craigslist for $100 spelled the end of the pretty poor efforts to make a homemade welder. That Miller is just great for everything except small stuff. I just saw an AC/DC version for $125. This is a real bargain. craigslist is great for these used buzzboxes. No need to pay full new retail. On the other hand, for a high end welder, it is probably better to buy new. You see Miller Synchrowaves for sale at 70-80% of new price. Too risky.

I think that I will resurrect the homemade welder project to make a micro welder. Got the argon and the flowmeter, just need some consumables. But it sure is nice to have a real welder to get that "must-do" fabrication stuff done.

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Many years ago I built an AC stick welder from 4 microwave oven transformers. It worked well and I completed many projects with it. Of course, it did not take me long to move on. That little junk welder got me addicted, it wasn't long before I had spent thousands on TIG welding and plasma cutting equipment. It's ironic in a way, I built that welder to save a few dollars. LOL.


Consider this your warning. :D

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  • 3 months later...
  • 6 months later...
  • 2 months later...

Mean Coyote

Your motor is more than big enough. You could technically run a home generator with that puppy!

Someone mentioned that steady amperage is what is necessary, and that is absolutely true. Also, like they said, hard to accomplish. Your voltage and amperage will change with load (before/after arc initiation), and also with engine speed. Ideally, a movable core isolation transformer would be useful here for this. However, you might as well buy a stick welder for the cost of one which will handle those amps. (or get one from a stick welder. :cool: )

I would get a couple of high amperage 400amp bridge rectifiers, and get rid of the factory diode pack. DC arcs tend to give a better weld than A.C. anyway.

If you want to try your hand at the electronics aspect of amperage regulation, I can attempt to either find or create a schematic if you desire.

Paul Andrulis

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Hey folks, just to let you know, I did build one. It's based on this design, On-Board Welder. I have mine on an old pressure washer frame, with an 8 hp B&S engine with electric start. I had to have a battery on it anyway, so it was easy to incorporate. I found a 100 amp alternator at Pull-a-part in Nashville for the basis of my welder. I worked very well with 3/32 rods, and you can hook 'em up to run straight or reverse polarity. Mine isn't running now, as the float stuck open, and filled the crankcase with gas, and the next time I started it, ugh.

9774.attach

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  • 3 weeks later...

I saw a super simple arc welder in Mexico, even took a picture of it but can't locate it. Five gal. plastic bucket full of salt water with a lid on it. About 4 copper rods spaced out and sticking through the lid, threaded with nuts to hold them in place and as I remember each rod was a different length. He clamped his hot lead of 110 volts to the top of the longest longest copper rod.
Then he came off the top of one of the other rods with his positive [stinger] cable. The negative lead from the 110 volt shop service was attached to the ground clamp of the piece to be welded.
I guess the amps were adjusted by hooking to a rod of a different length.
Didn't look to safe to this Gringo, but this is what he welded with every day. Use at your own risk. Jim

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