Making my own welding machine?

A post in the transformer thread made me think. I have a very large transformer with many windings. At least a 200 pounds beast.
http://igor.chudov.com/tmp/capacitors/
I hope that I can find a way for it to reduce voltage to say 30-60 volts or something, on those windings. Maybe rewind it a little bit.
I am going to have a 60 AMP subpanel in my garage soon, I am working on it anyway (compressor needs more juice etc).
Then, to have a rudimentary welding machine, all I need is to add a onboard overcurrent protection device, a rectifier big enough, and welding cables. Am I missing something important? I know next to nothing about welding equipment and wanted to tap into your collective knowledge.
Do welding machines need to be DC powered?
Thanks!
i
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On 4 Jan 2005 19:51:52 GMT, Ignoramus28225

Nope you can weld with AC, I think DC is nicer though. Look around on the web there are lots of great DIY welding plans out there and you have a good start with your transformer core.
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Thanks. I will definitely look for it. After I am done with the subpanel and soundproofing my generator, I may start working on a welder. I will create a webpage with progress pictures, just like Idid with my generator repair project. I appreciate your comments.
i
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That transformer looks like it has pretty beefy secondaries already. When you energize the primary and connect the secondary windings in parallel, what do you get for an open circuit voltage?
Most guys who make welding transformers remove the secondary windings and wind on a few turns of flat copper bar. If you want to convert to DC you may have to spend some serious change to get a rectifier beefy enough to handle the stress of striking an arc. Google for the terms "welder" and "snubber circuit" or something.
And do NOT fall in love with your transformer. In my neighborhood I see 225A AC welders for $50 several times a year, it would be a lot easier for you to start with one of those.
GWE
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I thought that connecting different secondary windings in parallel would be some sort of equivalent of a short.

What size would that bar need to be?

Do I need DC for a welder?

Good point. I might just look for a used welder. Imust say though, that Idid look for one and did not find anything cheap.
i
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"Ignoramus28225" wrote: (clip) I thought that connecting different secondary windings in parallel would be some sort of equivalent of a short.(clip) ^^^^^^^^^^^^^^ If the windings have the same number of turns, and you don't get the polarity reversed, they don't act like a short.
A "stick" welder has to have inductance in addition to the transformer itself, so that while you are welding, the current remains relatively constant. Particularly, while you are striking the arc, you are shorting the welder output. Without the extra inductance, the current would jump way up, possibly sticking the rod and turning it red hot.
I think building a welder is an interesting challenge, but if you try to weld with an unknown and imperfect setup, you won't know which part of the problem is the machine, and which part is you. I agree with the others who say you should start by buying an inexpensive unit.
Do you know about sci.engr.joining.welding?
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wrote:

That's why I said "different". They do NOT have the same # of turns.

I had no idea!
i
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Home Depot sells the Lincoln ac225 arc welder for 279.00 bucks. Cheap for what you can do with it. Of course, if sheet metal or aluminum is your fetish, your screwed without a tig welder..... MLM
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I am curious, how heavy would be a lincoln 225.
i
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About 80#. Bugs
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Here is a link to some items I made a few years back http://www.motherearthrecycling.net/welding/welding.htm
I would consider buying one, it might cost you less in the end and you can just plug it in and not worry about cooking something you didn't want to.

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wrote:

Thanks. The arc welder link does not work.

Thanks. I looked on ebay. Is something like this:
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&categoryF413&itemC44256919&rd=1
worth anything?
i

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Where do you live? Have you looked in your local newspaper's classified ads, your local "nickel ads", your local craigslist? - GWE
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On 4 Jan 2005 20:47:37 GMT, Ignoramus28225

Not much.
You want something more along this line....
http://search.ebay.com/lincoln-225_W0QQfromZR40QQsojsZ1
I bought one of these locally for $20 a few years ago. Ive outgrown it, but it was a fair machine. The Lincoln 225 is a decent machine as well.
I have both for sale, but shipping would eat your lunch.
Gunner
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Eventually she will succeed, perhaps with the help of your fellow man.
Life consists in putting off the inevitable as long as possible and taking what good and joy you can before her success.
Whether you attribute that situation to evolutionary forces, a fallen nature after Adam and Eve screwed the pooch, or whatever, it's no less true.
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Thanks, I will look for a cheap local one then.
i
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wrote:

i
It might be interesting and rewarding and even educational to build a welder with the transformer you have. It probably boils down to deciding what is more important to you, Building a welding device or Doing some welding. I own several Miller welders MIG, TIG and even one that does both. But, I prefer to use the stick welder I made from scrap. I sure dont suggest the junky-scrap welder I made is superior to the Millers, but, I sure like useing the ugly thing. The design considerations involved with making a decent stick welder are kinda interesting.
Jerry
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I have been having urges to mess around with machinery lately. So, I would not mind making a primitive welder. Any website suggestions?
i
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Ignoramus28225 wrote:

www.google.com
Search home made welder, build a welder, building a welder,do it yourself welder, microwave transformer welder, etc.
Lot's of stuff out there.
Cheers Trevor Jones
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Forget the welder...make a TIME MACHINE!!!

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On Tue, 04 Jan 2005 23:29:35 GMT, "Tom Gardner"
We know what YOU want it for, Tom. You want to go back to the point in time just before the perps came out of your shop so you can kneecap 'em, don't you?
(Let me know how it works, Iggy!)
-- "Menja b, caga fort!"
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