Thread: DIY Welder
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Old 01-04-2011, 09:04 AM
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ferball ferball is offline
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Join Date: Apr 2010
Location: NH
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Default DIY Welder

First off I love this forum, and I know most of you guys that read this will laugh and/or call me insane. I posted a few months back about a DIY Welder made out of microwave transformers. Some of the response were helpful, most were to the effect "Go buy a cheap welder". So I want to start this post off acknowledging that: yes I could buy a cheap welder, and yes playing with wires and transformers might kill me. That being said you can laugh at me all you want, just don't be shy on advice/experience that may help.

After melting the secondary coil for the second time on my MOT (Microwave Oven Transformer) Welder I decided a new approach was needed. So I had the brilliant idea of winding my own transformers and making my own welder from scratch. There is little or no info about this on the internet aside from the pictures below. I can find info about transformer theory and some of the math involved, but no decent how to nor the actual math to figure transformer output. Could I use a solid core for a simple welder, or does it need to be a laminate core? And could I use multiple taps off of the secondary to make the amps adjustable? And how hard is a shunt to calibrate and use for voltage adjustment?

The other problem I found with the MOT welder is I can not find information regarding actual voltage requirements for welding electrodes. I can find more than enough info about the amps but nothing about voltage other than what an over voltage bead looks like. But how much is "over voltage" 30v or 50v or 20v? I know it depends on the electrode, so can some one give me a clue there as well?

I chose this forum as opposed to a welding or electrical forum because the talent pool here is quite diverse and the information tends to be more practical than theory. So I figure there is enough know how here to make a functional DIY welder with minimal cost and readily available material, and yes I am dumb enough to try plugging it in after it is built.
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