Instructables
Picture of Making an ARC Welder - Part 2 of 2
How to convert scavenged microwave parts into a useful arc welding machine.  This is part 2 of 2, and focuses on the electrical system and finishing touches.

More projects at www.thekingofrandom.com

Before you watch this, make sure you've seen Part 1.
 
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Step 1: Watch the Video!



WARNING: Stick welding, and/or the modification of a Microwave Oven Transformer (M.O.T), can be very dangerous and presents risks of UV radiation, shock hazards, burns, fires, fumes and a multitude of other risks.  This project should not be attempted without a thorough understanding of electricity, adult supervision and adequate training.  Misuse, or careless use, of tools or projects may result in serious injury and/or death.  Use of this content is at your own risk.

Step 2: Transformer Platform

Picture of Transformer Platform
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I started this part of the project with a scrap piece of 3/4" birch I had left over from my "Router Table" project.

The measurements for the board were 7"x10", and that keeps this about as compact as practical.

I found a piece of 2x2 as well, and screwed it onto the center of the board about an inch from the edge.  

Two pilot holes were drilled in the top to accommodate our electrode lugs.  

I decided to use lugs here rather than keep it all one continuous cable, because it gives the option of changing out electrode cables, or easily modifying the electrical output for future projects.
killer142 made it!6 months ago

This was a fun project !!

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Zenoah11 year ago
Really nice project!
I live in europe so we have 230/240 from our outlets, would it be possible to use just one MOT? or would the load on one MOT burn out way to quickly?

Jb
Hey, love the project!
I'm just a little confused on this section here. Why can't you simply plug each transformer into an outlet individually?
Thanks
Evan
sconner11 year ago
I have to say I like most of your posts, but this one is a bit scary. I can see somebody connecting 2 hot leads together and shorting the house circuits.
Instead of wiring the primaries in series and risking one's home with very sketchy and easily mistaken connections, Simply make sure your windings are in phase with each other and wire the primaries in parallel at 120V and leave the secondaries in series. This should accomplish the same voltage without using the dangerous 2 outlet hack although this limits your amperage draw to 15 or 20A. OR wire up a proper connection to the 30 or 50A dryer or stove outlet. And for God's sake, Put fuses in your electrical primary circuits! Another good practice is to put the rig in a metal box and connect that safety ground wire to it. Be safe out there.
The dryer and stove are already 220V by the way.
The 3 prong dryer outlet has the 2 hots and ground.
A 4 prong stove outlet has 2 hots, a neutral (center tap) and ground.
Misac-kun1 year ago
I was wating for a ible like this from you for so long!
sscsnake1 year ago
I see you found out how the 240v and 120v systems in your breaker work. The 120v is just the center tap from the 240v. I was wondering why you decided to run the system off of 240v instead of 120v? You could have ran the transformers in parallel with each other and had gotten the same result with half as much voltage. Then you could have ran each transformer separately or have used the center tap. I'm not trying to dis your project or anything but thats how I would have hooked it up. But what do I know, I'm only 15. I still have alot to learn. Are there any advantages to 240v besides half the amps?
eleechapin1 year ago
Wow!!! Nice job!
Perfection as alway's......can't wait for the scariac video to come up
pfred21 year ago
You should make a metal enclosure for your welder with your welder. Metal holds up better to sparks than plastic does. I'd probably ditch that kindling you attached your transformers to also. Now you should see if you can rectify your welder. DC welding is a lot nicer than AC. Then you need to make an arc starting circuit because that is nice to have too. My Miller goes up to 200 amps and the power cord on it is the diameter of a garden hose. Just something to think about there.