Picture of How to Make the Metal Melter
In this project you'll learn step by step how to modify a microwave oven transformer into a high-current device that can pump out 800 amps of electrical current.

If you liked the Metal Melter you saw in a previous project, here's how you can make your own!

Step 1: Find an Old Microwave

Picture of Find an Old Microwave
Start by finding an old microwave for free. The bigger, the better.  

You can find them in various places, like on free classified adds, or in your neighbors garbage can, like where I found this one.
electrofrk made it!8 days ago
I don't understand how replacing the secondary with fewer turns will step up the voltage. I thought that you need more turns in the secondary. Someone please explain.
兰亭月1 month ago


Sir / Madam

I am a Chinese who do not understand English, should not understand English, I rely on translation software, see your article! But there are still a lot of places do not understand! I'd like to see the video! It's a pity that I don't know where to look at the language!

This tool is good, can melt much of the metal?

"I was using the translation software to write, it may make you feel tired! I'm really sorry.

awep2 months ago
Can if the 2 AWG wire at the top?...
Crazyconnor776 months ago

does it have to be a microwave transformer?

Dan.Broomhead7 months ago

Question: Why wouldn't you use a cable with a higher ampacity?

2 AWG is only capable of handling 130amps max (http://www.armstrongssupply.com/wire_chart.htm). Yet even just using 2/0 AWG bumps your ampacity up to 195amps. Would a cable with a higher ampacity heat up slower during use than one with a lower rating? I'm just trying to learn as much as I can before making one of these. I'm also trying to make it usable for longer periods and possibly larger items, or sections of larger items. I'm a hobbyist blacksmith and this would be awesome to use if it could be modified somehow for forging.

nathanaloysiusbash made it!10 months ago

I just made this. Is it supposed to be really loud? Sort of like a hairclipper? Anyways a few tips for anyone who tries this: 1.A grinder makes this project way easier, grind out the welds that hold the E part of the transformer on, then knock it a bit and it will come off. 2. Also a grinder makes it a lot easier to get the unused coil with all th wraps of little wire out. Just grind through it a bit and then pull out some strands till it gets loose. 3.You're probably going to mess the coils up up doing this so wrap up the ends of the coil you want to keep with tape or something to protect them from getting little bare wire spots. 4. Get more feet of 2 gauge cable. Get like 10 ft. I used 6 feet and the cable ends ended up a bit short. 5.Wear some dark sunglasses or better a welding mask when you try this out. It's real bright the sparks. 6.I used wire tires/zipties to hold it back together after reading that somebody used a hose clamp. The zip ties didnt work great, I couldnt get them tight enough. Do get an appropriate size hose clamp or better a couple. All in all awesome project! Havent figured out much use for it yet. I'm thinking welding. I'll try the spot welding instructables next. Theres also one called 'welding for punks' that seems to use this approach. Thanks King of Random!


Actually just use big hefty zip ties to hold it back together and make a slot for them to go through so they wont move around. Works great.

wait i thought that amps or current were what killed and not the volts because from what I've heard even 2 amps is enough to kill a person..... or was the information wrong? And it doesnt need to be plugged in or anything?

5mA is enough to kill depending on personal resistance and how it goes through your body, this is a high risk project b advised

he volts need to be sufficiently high to pass through the skin. so in truth, volts can contribute to wether you are roasted or not. and these high voltage devices often have capacitors that can store a charge and potentially kill you
veinha2 years ago
how up the voltage to 12V?
The King of Random (author)  veinha2 years ago
More turns of wire on the secondary coil. Probably about 11-12 turns would do it, but you'll have less amperage as a result.

can u cut the plug for the microwave and attach a nail and use that instead?

KarenH11 year ago

My son made this and it makes a loud humming noise that is scary! Is it supposed to do that?

jmurray331 year ago

hey! i just took the primary coil out of my transformer and scratched it a bit ( it was glued in pretty strong) and some of the paper wraping ripped a bit. i was wondering if i just needed to get another transformer or if it would work just the same?

I_StarkGuy1 year ago

I just finished mine!!!!! Moving on to the spot welder!!

Benjamick1 year ago

Oh your Majesty, King of the Random, i have a question: i need a 6V DC transformer that puts out at least 1360mA. I didn't feel like looking all over for it, so i looked around what I had, and found a 300mA 6V DC transformer. Is there any way to modify it and make it put out 1.36A or more ?

ccrome1 year ago
Heh, my microwave pooped out, so I just built the metal melter. Awesome! I used #4 welding wire from a welding supply store. That stuff is super supple and flexible. Very nice cable.

Also, the #4 wire allows me to wind anywhere from 1 to 2.5 coils on the secondary WITHOUT disassembly! It nicely just scoots through the slots. If I have something a little higher resistance, I just increase the output voltage by winding another loop!

I love your videos! I think I'm gonna have to go get a projection TV now too...

connorACIII2 years ago
I found some 2 awg cable at Lowes but it's not pliable at all. are you sure thats the right stuff?
pwnag32 years ago
Don't weld it even if you can, transformer iron (silicon iron) spits like crazy when welded
(i speak from experience), also it may melt the insulation.
The King of Random (author)  pwnag32 years ago
Thanks for the tip! How do you suppose they weld it in the first place? It would be good to have a solid connection to help reduce noise from vibration in some cases.
Looking at the weld, I would say TIG or PLASMA at 100-150 amps, 30" per minute travel, argon gas shield, in an automated machine, although you could do it by hand with these parameters.
Thanks for your reply! It's impressive you can tell that by looking at the weld .. must come from experience? What do you do? I don't suppose you could do it with a stick welder could you?
You could but it makes a mess...you need intense pinpoint heat with a good inert gas shield...notice the weld is about 1/8" wide and 1/8" deep with little heat mark beyond the edge of the weld, that indicates high travel rate. You might also use a CO2 laser in an inert atmosphere.
25 years ago I designed servo controlled welding systems for defence contractors.
Spot on! Especially the part about high traverse rate. If you try it with TIG I would suggest submerging it to the top of the winding to heat sink the unit. Ya gotta be a little creative for this...
wire feed (MIG) welder; grind the area to be welded to free it of silicone. MIG is fast enough to prevent heat buildup
you could try a large stainless steel hose clamp around the out side to stop vibration. i have an old microwave, and need of a spot welder. i think i'll try that when i see if i can make one. thanks for the idea.
Excellent suggestion. Thank you for the idea as well, and best of luck!
I tried welding one together with FCAW. the laminations popped, everywhere, and my wire insulation caught fire
pwnag3 pwnag32 years ago
Although you COULD do some tack welds without much worry just set up some sort of shielding so sparks don't hit the wires
"submit" does not appear under the challenge
zacker2 years ago
how is it, you can touch both ends of your cables and not get zapped but when you touch them to a nail, it melts it? is it because the current flows through the metal faster than a human? or is it something to do with resistance?
The King of Random (author)  zacker2 years ago
It's Ohm's law. V=I*R. In this case 2 volts = (unknown current)*(resistance of my body).

The resistance of the body changes constantly, and depends on moisture and many other things, however I usually measure in the multi mega-ohm range, which puts the current (if any) in the less than 1 micro-amp range. It would take 100 Milli-amps to stop my heart .. and that's about a hundred thousand times more current than what would be flowing through me.

However, metal is millions times more conductive than me so can allow the full potential of the current to flow .. so in that case we can have around 800 amps flowing through the metal.

Does that make sense?

It's not about the current, it's about the voltage. Everything conducts electricity, even things that are used as insulators, you just have to get the voltage high enough. Dry skin doesn't conduct electricity until you have upwards of 1000's of volts. Once you reach the threshold for conductance, current will flow and you will have a shock. This is why stun guns and tasers are such a high voltage.

You are correct though in that it's the resistance of the human body that keeps us from getting the shock. It is what requires the voltage to be so high.
I see what you're saying, but it is about both voltage and current, because they work together.
The thing is, if the voltage isn't high enough, there will be no current flow. While current is what will hurt you, it's flow won't exist unless the voltage is high enough to overcome the resistance of your skin.
Yep, exactly. Wasn't that the reply I gave to sacker?
Well, kind of, except you never stated that it was the low voltage that made it safe. This had to be inferred from what you said, which is why I clarified with my post.
You're right in all of the above! Thank you for your clarification :)
yeah... its sorta what i thought... i just had it backwards, I thought it was because the metal had more resistance than the body so more amps would be sorta backed up instead of going right in and out..lol well, that explains it. thanks!

BTW, Im the one on you tube this AM with the bottle cap shooter...lol
The King of Random (author)  zacker2 years ago
Oh yeah, sweet. Thanks for all your comments!
no prob, thanks for all the cool posts... gonna possibly mess with my 55" fresnel this weekend.. see how that goes.
The King of Random (author)  zacker2 years ago
Just don't try this with your tongue - unless you need a flaming pierced one.
The King of Random (author)  ToolboxGuy2 years ago
Haha I agree!!
Your youtube channel is amazing, full of awesome vids of things which I cant do often at home
I finished making mine and you can literally play with it all day! The only thing I still need is some thick hauge wire because I'm currently using taped-together strands of thinner wire just to test it.
Good 'ible, Clear enough for me to have a go myself... I have been given a 240v (I'm in the UK) m/wave transformer but I don't know which are the primary and secondary windings - how can I tell? - or are they always primary on top, although I have seen some side by side designs.
A few ways to tell are:
the secondary is very thin wire whereas the primary is thicker
The secondary has one wire output and the other end is grounded to the transformer
The primary coil has two spad connectors
The secondary is mostly wrapped in paper and the primary is mostly bare
Thanks, I seem to have got it right then.
manutea2 years ago
hé hé hé; very interesting; thank you for posting this idea.
nate711732 years ago
I will never, ever understand how meters can take readings off such colossal amperage without exploding. Any insight? (Obviously u don't want to go over max rating)
The King of Random (author)  nate711732 years ago
In this case I was testing for voltage. If I set the meter to measure current, it would blow the fuse easily as the fuse is only rated for 10 amps :)

Isn't it strange how the test leads don't melt? They must not close the circuit....
The King of Random (author)  nate711732 years ago
Correct. Voltage setting is different than a closed circuit setting.
Thank you!
fidgety22 years ago
input power is standard 120 volt and i have 2 wraps on on my secondary but i have found the problem unfortunately it is a busted primary coil is it possible to use a different coil of wire for the primary coil if the existing one is busted i have a coil of wire from a old electric motor that looks like it will fit but is this advisable

much thanks,
The King of Random (author)  fidgety22 years ago
If it's got about 100 wraps of wire you can probably get away with it. If the breaker still pops, you can try adding more turns of wire on the primary. Good luck!
fidgety22 years ago
i have made one of these machines but in operation i keep blowing the fuse how can i prevent this
The King of Random (author)  fidgety22 years ago
What is your input power, and how many wraps is on your secondary?
A suggestion to make it more versatile, although also a bit more expensive. If you took a set of heavy gauge jumper cables and split them into two cables and cut those in half you could use them as a classic arc welder. Wind the cable around the transformer just like in your original design. One end clamps to somewhere on the object you are welding and the other holds the sacrificial bit of wire. You could do something like your assembly with the switch at that end. The beauty part is that you would end up with three spare cables.
absingh2 years ago
absingh2 years ago
but I appreciate your work and its an excellent project
absingh2 years ago
from where does you get the connection for the transformer?
where is it?
a very intresting project
iFirefly2 years ago
Very interesting and dangerous! It looked like you were melting a galvanized lag bolt there - did you feel ill for a few days afterward? Welding or melting Galvanized parts produces a toxic compound that causes illness when breather in, so please be careful!
The King of Random (author)  iFirefly2 years ago
Thanks for your concern. I'm aware that zinc oxide fumes are dangerous, and I've burned a lot of galvanized metal and haven't felt any ill effects. Is it a theoretical concern or do you know someone who has been injured or sickened by them? Thanks again!
The zinc fumes cause edema...fluid build up in lungs and around heart, a small amount makes you ill, a large amount causes death.
I have never been affected personally because I don't do it, but I have spoken with a few welders who have leaned the have way. Look this up on any decent welder manufacturer's website to get the details.
Caspar iFirefly2 years ago
The "toxic compound" is zinc oxide. Not too toxic: it's used in tablets where there is a danger of overdose. The zinc makes you vomit before the overdose affects you.
Trike Lover2 years ago
Very interesting instructable. I've more or less ignored microwave ovens as a transformer source, but that's about to change.

A couple of thoughts occur to me. 1) If you don't have any insulated 2 AWG wire, it might be possible to strip, several lengths or, say, 6 or 8 AWG, then lay up the bare stranded copper side by side. After that, a coating of "liquid electrical tape, followed by several layers of good quality electrical tape, like 3M #77. If you packed the separate stripped cables close together, you could approximate the current capacity of 2 AWG. Since the voltage is low, a careful use of tape insulation will work.

If you are looking for carbon electrodes for spot welding, check with a supplier who services the ceramics trade. I picked up two 9 inch long 3/4 inch diameter carbon rods, with pointed ends, for $8. I think they're used in kilns, but I've used them for an improvised spot welder with a car battery as power supply. Works just fine. The rod diameter is more than sufficient for 800 Amps, BTW.

A second thought that comes to mind is to wind, say, 8 or 10 secondaries of small gauge wire (have to consult a wire table, but I'm guessing 16-18 AWG stranded, with sufficient turns to give 5 or 9 volts, depending on requirements, at a current of of 1 - 2 amps maximum. This would form the basis of a single multi-output power supply for a guitar effects pedal board, There would be 9 to 12 secondary windings, each going through a rectifier and a fixed voltage regulator IC like an LM 7805 or 7809. The secondary voltages chosen would, of course, depend on what your various pedals need, but most effects pedals run happily at either 5, 6, or 9 volts DC at a maximum current of 1 Amp. This would eliminate a huge heap of assorted wall warts! I realize this is a big departure from a metal melter, but the transformer size is such that it would be ideal for multiple low-voltage low-current secondaries.

Such a transformer is commercially available, made in the U.S.A., and is not expensive, $25 or so, but the shipping on it is a good deal more than the cost of the transformer. So rolling your own strikes me as a good idea with a core and 120 VAC primary readily available.

I plan to try out your metal melter - I have about a thousand pounds of lead, in large awkward slabs, that needs to be melted and poured into more reasonably sized ingot molds. I think I'll do this outside - I expect the vapours and the stink will be fearsome.

A long time ago, I wound transformers for RF amps in my ham radio station - the biggest had a 5 kV secondary - not something to fool around with. That one also weighs about a hundred pounds, and cores like that are just about impossible to find nowadays. I sill have The Beast lurking in the basement, but I will probably be changing the primary from 120 VAC to 240 VAC, and dropping the output to 4 kV - plenty for the current amplifier project.

Thanks for this great tutorial on microwave transformers. Great stuff.
The King of Random (author)  Trike Lover2 years ago
I'm glad you liked the project and a re-kindled interest in modifying your own transformers. Best of luck in your projects! They sound dangerous, but it also sounds like you have enough experience to know what you're doing :)
Edgar2 years ago
Metal melting!
Liked, voted, and subscribed to the videos.
The King of Random (author)  Edgar2 years ago
Thank you Edgar! I'm glad you liked it. Thanks and welcome to the videos :)
I have a Gizmo builing Blog, tomorrow, I'll mention your Videos. Good ideas come of seeing lots of stuff...
The King of Random (author)  Edgar2 years ago
Awesome! Thanks for the kudos, and if you want to hit me back with a link to your blog, I'll check it out :)
Here it is:
The King of Random (author)  Edgar2 years ago
It looks great Edgar! Thanks again for the link, and thanks for your quick reply!!
We got to keep bringing good stuff up...
pietzeekoe2 years ago
I'm on a 240 volt grid, so how many turns would I need? Also I already saw your spot welder video and was wondering why it wouldn't trip a breaker.
ilpug2 years ago
One question... So, this runs at 2 volts but a massive amount of amperage... This means that you can touch the contacts and not be shocked horribly?
mortnoir ilpug2 years ago
It’s not volts that kill it’s the Amps…. you only need 50mA across your heart to kill you, there is enough in a 9v battery to kill you under the right conditions.
The minimum voltage it takes to kill you is roughly .006 x resistance to ground (in Ohms). Touching the contacts would be a VERY bad idea.

1100 volts wont kill you unless the current is high. voltage X current = power(watt). So if the current is 0.000000001 amps, and 1100 volts you wont feel a thing. But on the other hand, 1 volt and 10,000 amps will fry you instantly. So it all depends on the current. Also if it is AC it will do more damage.
The King of Random (author)  mortnoir2 years ago
You're right that amps are what do the damage, but volts are what deliver the current. I touched the terminals with soaking wet hands and still didn't feel anything. 2 volts isn't enough to deliver any current through my heart, but I'm not recommending it.
The King of Random (author)  ilpug2 years ago
Thanks for asking! It's comparable to touching the terminals on a car battery.
Would it be theoretically possible to clamp it together without the glue and then use it to weld itself back together?
I've thought about that, but the core is made of laminated sheets and I'm not sure how well they would weld together. I'll give it a try one of these days just for curiosity!!
your instructable got featured! congrats... You should consider converting more of your videos to step-by-step instructables, especially HOH generator...
And of course, you get my vote :)
I'm considering it :) Thanks for your suggestion .. and I just re-made the HHO video, so when I post it later, I'll do the step by step instructable to go with it. Thanks!
nice work on the new video... love the professional look of your generator.
Thank you! I'm glad you liked it :)
Ok, just added the HHO generator instructable with the re-made video. Hope you like it.
qwerty9242 years ago
that's awesome...i'll try to make that sometime:)
qboid2 years ago
That is useful. I'll try it out one day.
PS. Small grammar mistake in the subtitle.
The King of Random (author)  qboid2 years ago
What is the mistake? I didn't find it.
Sorry the Know you Know! subtitle Instead of Now you Know!

This opens up a world of ideas the more you think about it.
The King of Random (author)  qboid2 years ago
Thank you so much! I've made the change, and really appreciate you pointing that out :)
No problem. Keep up the good work.
The King of Random (author)  qboid2 years ago
Thank you! I'll check it out!
Wingloader2 years ago
How much power is used when this is on "stand-by"? It seems like this would use a ton of power just plugging it in. If you stick a piece of copper into an outlet you get a flame and melted wire. Isn't the primary coil just a piece of wire? I know it has turns that go around a metal core, I just can't get my mind around this.
The King of Random (author)  Wingloader2 years ago
0. Zero, zilch, zippo. Nothing.

The unit doesn't have a standby. It's just on and off when you press the button.

I'll probably make a detailed instructable about this sometime later this week.

Have you seen the video?
My question was so dumb I am embarrased. :-)

When the switch is on, how much juice do you think it uses? Maybe 20 amps or so (at 110v etc.) :-)
snatr2 years ago
Nice video. As always, they make things seem a lot easier to do than they are though :)
The King of Random (author)  snatr2 years ago
Thanks :)
so there is no power source it's plugged into? i didn't read any about plugging it in, so i'm curious
Did you see the video?

Please, answer, the insulated copper cable tip melts never?
It will melt if you short it out over long periods of time. Look for my video called "metal melter" on YouTube and it shows the insulation melting. But as long as you use this in short burst of 15 seconds or less, you should be able to use it indefinitely.
aylbegi2 years ago
Whats your power source? 230VAC?
The King of Random (author)  aylbegi2 years ago
I was using 120VAC on this, but 230 should work fine? .. I imagine it will just increase the power output.
codongolev2 years ago
do you know if it would be possible to strike an arc and actually use this as an arc welder using some jumper cables and flux-infused welding rods?
The King of Random (author)  codongolev2 years ago
No, the voltage would need to be closer to 30-60 amps to get a usable arc, but I will be doing that in a future project if you stay tuned? :)
i think you meant volts and there is a nice plasma cutter that could be incorporated into this design elsewhere on this site.
The King of Random (author)  rexferal2 years ago
Oh yes, I did. Thanks. Looks like I started out saying volts, and then switched. Strange, but thanks for the correction! Do you have a link to the plasma cutter? Sounds like fun!
techno guy2 years ago
and where can I get 2 awg copper wire?
The King of Random (author)  techno guy2 years ago
Try an auto shop, or if it's too expensive, you can try 4AWG wire from a hardware store like home depot. It won't last as long, but it should work fine for experimenting, and it's not as expensive.

techno guy2 years ago
do you just plug this in directly to the wall?
The King of Random (author)  techno guy2 years ago
I do (kind-of). I link the primary coil directly into the mains power (wall outlet). That's probably the most dangerous part about this project.
gfwhell2 years ago
I like the simple construction of this device and wondered if there would be enough power available to "melt a coke can" ? I invisage a frame to support a spring or weight loaded platform to crush the can when the power is supplied..Hopefully this would leave a flat "coin" as a base on which to build your space saving "ali ingot"
The time for the melting of each can would be fairly brief.
gfwhell gfwhell2 years ago
most micro wave cookers use only half cycle while running the magnetron under load,and are fan cooled,so I expect the insulation of the transformer wire is high class, never the less heat build up could be a problem. Perhaps two transformers could be used to share the load and dissipate the heat,with their greater surface area . the secondaries could be wound in series to give a higher amperage for a shorter time, the contact end like most resistance welders could be liquid cooled but now we are getting into some complicated stuff.
The King of Random (author)  gfwhell2 years ago
Complicated sounds like fun! I think a helpful idea would be to wind more wraps on the secondary to give it a higher voltage. It will lower the amps, but I doubt that would make a serious difference because there will still be plenty! Would an induction furnace work better for your project? I'm not experienced with them but have heard about them a bit.
The King of Random (author)  gfwhell2 years ago
Thanks for asking! The coke can is probably aluminum, which is fairly conductive, and that's not good for trying to melt it. The metals melt from electrical friction, so I suppose it would work, but the secondary coil on your metal melter would probably get very hot before it did?

It's worth trying though!
Caspar2 years ago
How would a water-cooled copper tube go as the secondary? I think plumbing copper tubing has slightly higher resistance than OFHC copper, but would be ok.
And, for safety, a spark shield over the mains wiring would help. I see a "version 3" coming up!
The King of Random (author)  Caspar2 years ago
A water cooled secondary? I've never thought about that, but think it would be a great idea! It would still need to be insulated, but you could pump water through the inside and Instead of burning up the outer coating when it got hot, perhaps it would just evaporate the water instead? Making for longer run-times? Cool idea!!
vashok2 years ago
Excellent Idiyas.Thanks dear
The King of Random (author)  vashok2 years ago
You're welcome!
Great video and Instructable !!
I had never thought of using a scrap power supply transformer from a microwave oven>
I have been trying to figure out how to "Spot weld" some flat head stainless steel screws to a stainless steel shield .
I WAS toying with the idea of using my AC/DC stick arc welder for this by turning it on quickly using a low voltage foot pedal and contactor/relay for turning the high voltage /high current mains supply for the welder off and on after I had set the 2 pieces together.
Your idea is much better and also would have a better control of the current coming out of it for my purposes.
Good idea !!
Keep up the good work.
I'm glad you like it! Thank you for your feedback, and all the best in your project!
K_Igor2 years ago
What input voltage, 120 ---- or 220
The King of Random (author)  K_Igor2 years ago
120, but 220 will work as well. Just puts out more power and gets hotter faster!
MichaelN2 years ago
Having done this before, I HIGHLY recommend you don't separate the transformer core like this. If you use a sharp chisel you can cut the secondary winding on both sides then use a metal rod to knock out the pieces left in the core. Obviously be careful you don't damage the primary. Winding the new (high current) secondary is actually pretty easy even with the core intact. I bought high-current weldng cable by the meter at a local machinery supply place.
The King of Random (author)  MichaelN2 years ago
I've done that before as well, and it's a reasonable choice for making this high amp transformer, but cutting the transformer core is great for winding larger secondaries, for stick welding. Why would you HIGHLY recommend against separating the core? I see no ill effects?
uncle frogy2 years ago
I do not care what Ohm's law may say I am not touching with my bare hands a live circuit or bare wires that are hoked up to the mains while it is energized . better safe than sorry, belt and suspenders thanks.
uncle frogy
The King of Random (author)  uncle frogy2 years ago
That's a wise choice :)
I like most this project I will try for my spot welding work thankyou.
You're welcome! I'm glad you liked it!
mrpesas2 years ago
How is it powered? I'm assuming the wall (120v AC) but I don't see it in the project and I'm slightly confused.
The King of Random (author)  mrpesas2 years ago
Did you see the video? Your answer is in there. 120VAC powered into the primary coil. Thanks.
Huzudra2 years ago
If you wound the heavy cable through more times you get more voltage, but do you get more amperage as well? Does the primary coil get hot? Would mounting it inside a box with a fan help any? I assume this is driven by ordinary 120V house current?

I'm interested in this for home use to heat and free rusted/seized bolts and nuts!
The King of Random (author)  Huzudra2 years ago
If you could wind the coil more then the voltage would go up, but you'd have significantly less amps available. Also space is an issue and there isn't enough room to wind this cable anymore in this transformer.

The Primary hasn't been hot for me, but I haven't run it continuously for more than 40 seconds at a time, and typically only about 10 seconds.

I run it on 120VAC, but suppose it would work on any AC.

Cool practical application idea! I hope it works!
maxhack2 years ago
Thank you so much, this looks so incredible, am sorry if i cant get this right, but cant you just cut the start of the secondary coil and start manually unwind it until end then enter the new coil inside hall and wind it without even needing to cut transformer to 2 pieces

beside am also sorry, but in next step 5 you said output is 2v, i believe input is normal 220v ac power from primary coil side, but how to melt iron? should it be replaced touching the "added" coil from a side and the other side touching same coil other end? thanks in advance and sorry for my bad english... and slow understanding :D
The King of Random (author)  maxhack2 years ago
You are right that you can cut the secondary off without cutting the transformer, but it is difficult. I wanted to show this as an easy method, and it's the method I will also use when making a stick welder in a future video.

In the US, our mains power is 120V, not 220V - So if you use 220V you will get even more power. Higher voltage and higher amps! :)
didibemi2 years ago
Your picture's were great! Nice instructable!
samaddon2 years ago
Hey, i asked you some questions previously and you said i will give a brief explanation in this instructable but still i am out of the knowldge of the gauge & turns of the primary coil. But still i've developed a prototype bu the voltage is not enough it can only melt some short wires.It's over 0.45 volts so it can only melt some short distant wires!
but lastly it was awesome ! i am running to make this out! and i've also build HHo generator but it did'nt worked i've used filtered water from a company not distilled!and supplied 24 volts from the transformer with one diode bridge any suggestions? cause it noly emits some foms not the gas!
The King of Random (author)  samaddon2 years ago
Thanks for your questions. You should see your answer in the instructable and in the video as well. The cable is 2 AWG insulated stranded copper wire, and the # of turns is 1-3/4 on the secondary. The primary is the original from the microwave and is about 100 turns. I hope that helps!

Best of luck!
nanosec122 years ago
Man this is one dangerous Instructible....but I enjoyed it enough to begin 'following' you.

Nice work
The King of Random (author)  nanosec122 years ago
Excellent :D I'm glad you enjoyed it and I'll be seeing you around!
zacker2 years ago
man, i do love your projects...
The King of Random (author)  zacker2 years ago
Thanks again Zacker!!
zacker2 years ago
is there a way you can drill through the two halves of the case (E and I) and use a long bolt and nut on each corner to hole it together?
The King of Random (author)  zacker2 years ago
I wouldn't think so, since the core is made of thin sheets of laminated iron stuck together. I think that while drilling the hole, the pieces would fray apart and your would damage the transformer core.

Thanks for asking!
dude seem's this video is unlisted for the youtube subscribers
which includes me obviously
Thanks for your comment. It's unlisted because I'm not releasing it until next week :) You found it early!