This is a nice compact MOT power supply that I created, it uses two 120V MOT's and some other things that can easily be obtained, I built this entire thing for free out of stuff laying around in my house and from microwave ovens that I took apart.

*A MOT can kill you instantly or give you a really nasty shock and they are not toys, I have been shocked by one and it was freaking scary and painful so BE CAREFUL! i am not responsible to any damage caused!

Step 1: You Will Need

Two MOT's
A light switch. I found one in my dads tool chest
A inlet from a computer power supply or something like it
A PFC capacitor (optional). 80uF at 120V+ should work just fine. I got mine from a garage opener in a junkyard
Some .250" female spade connectors (bag of 50 for $2.20). You will also need some smaller ones for the inlet but I don't know what size
Some 14 awg wire. Speaker wire or an old power cord will work just fine
A 13" piece of 2 x 4
A soldering iron and solder
A drill
Some screws

Step 2: Position the Transformers

find a good place for your power inlet, switch, and capacitor and lay it out on the left end of the board. Next secure it all, i used epoxy to secure the capacitor and the power inlet since they can be screwed in. Connect the live terminal on the inlet to the bottom lug on the switch and connect the top lug on the switch to one side of the capacitor terminals. the neutral terminal on the inlet should be connected to the adjacent terminal. Last connect the ground to the ground screw on the switch.

*The bottom of the switch was bent so it would be at an angle.

Step 3:

The second, but probably main thing to do is to position the transformers. I prefer to put them on the right hand side of the board and have all the other stuff in the left side. I put the primary connections facing the back and the secondary connections facing the front. After you have your transformers just the way you like them, leave the transformers on the board and use a sharpie to make marks through the screw holes on the bottom. After you have marked where the screws will go, remove the transformers and drill holes for them, then put them back on and screw 'em in.

Step 4: Wire Up the Transformers

The transformers are wired in anti parallel after the capacitor. The cores must be grounded or it will not work properly and plus its kind of a safety thing... Not much else to say here, just follow the schematic

Step 5: Changing Transfomers

As you may have noticed in pictures of the finish product and pictures taken during construction, I have different transformers. My friend gave me both of those transformers and i was able to get another one that was almost an exact match so i switched one of the other transformers for a better look and better performance.
What you do is remove whichever transformer you want to replace, put the new transformer on the board, drill new holes if needed, and wire it up. simple as that but you may need to rewire the whole thing if the primary terminals are in a different location or if the have different connections.

Step 6: More Power!

The two transformers alone can give some pretty nice arcs but some resonate capacitors on the output can give some much better arcs. All you need if four high voltage capacitors from the microwaves and wire them in series parallel and connect them to the output and the arcs can be drawn out much longer and also seems to draw less current. You could also just use one capacitor in series with the output but it will burn out pretty quickly. Putting the capacitors in series parallel does not change the over all capacitance but does increase the power they can handle. When drawing arcs, make sure to keep the metal casings on the capacitors touching or the cases will spark to each other.