diy microwave spot welder - The Transformer

In this is video, i'm going to show you how
I extracted the big transformer from the microwave oven
and repurpose it for use as a spot welder.
I'll show you how I disasembled the transformer and rewired it to give a low
voltage and high current, then put it back to together.

[stewartbruce]

Your daughter is beautiful and precious. I really enjoyed the bond between the two of you.

[edheide]

Good education for me, I learned from your video so I can do it better Thanks.

[michaelgasperik]

2/0 welding cable works well for the new secondary coil. You can get 2 turns in and about 2 volts out also with a little bit of Vaseline you can get the cable in without cutting the transformer body apart.

[jamierichards]

All that trouble and expense you went through with bare wire, why not just buy some insulated number 2 or 1/0 wire and be done with it? You put more effort into it than was needed, but I'm glad you got it working.

[bikingmnviking]

11:31 Congratulations you have just turned a quiet microwave into a near school bell-ringing hystersis that reminded your poor daughter to go to her next class.

BTW -- input turnings of the primary windings are NOT about how much voltage comes in but rather their thickness is the FIRST and most important limiting factor on the amount of amps that can safely be passed through it. Plus why didn't you just cut it from the bottom so as to not risk damaging the primary coil?

Easier yet would have just been to cut the secondary coil with your gringer and pull out the secondary coil as a U shape and save it for scrap or making electrode tips out (it'd make a lot and much easier to bend fine wire than thick wire. The enamel coating melts right off with your choice of heating method. And you can control that and just use the ends. In fact if you cut the top coil you could probably just cut the bottom coil into 30 inch long lengths and use it as your new output coil. That shellac coating is way better than the green stuff you around your secondary coil.

Good vids but my did they have to be so long and convoluted? You really took the time consuming route, 3 d printing and turning things...for all that time wasted you could have worked somewhere and bought one in one or 2 days work. With your lathe you even had a chance to make liquid filled tips and you didn't. You know what you're closer to? More than enough current for a car starter.

All you need to do is adjust your windings to get 12-18vac and then buy a bridge rectifier (Or use a bunch leftover from alternator rebuilds because usually there are 3 and one goes bad -- you need 4 unless you centertap your output in which case 2 will do perfectly.) I'd run several in parallel to get by the lower current rating (most are 40-100 amp these days.

What'd be really interesting is to see a spot welder you could plug jumper cables into and doubles as a car starter, no? VERY possible and you'd not far from it and it's practical. You'd know a lot more about electronics by then, too. Diodes you can get cheaply for rebuild kits... or arc welders. It doesn't need any filtering/smoothing to run to a battery or car starter. Most cars can easily run 15vdc and all that happens then is a very very slow boiling away of the electrolyte if you're in a warm/hot state. During winter it wouldn't even be noticeable.

Centertap means exactly what it sounds like. Just solder/braze it well and wrap a few layers of electrical tape around it (the liquid stuff is probably better for this app... I've even used on the HV part of our snowblower that goes to the spark plug and it holds up fine) and affordable. Have fun!

[siggyretburns]

Instead of using romex, flatten out copper tubing and fold it lengthwise

[johnaffleck]

They're called magnetic shunts; and no; they do not "help with heat"; they are one of two serious mistakes you made; they go in the trash; and number one; you do not cut the core apart; you saw the secondary winding with a hacksaw and drive it out of the winding window.

[szaki]

So much work!
Ebay sells new spot welders starting at $130!

[mock-m]

Best video. Showing everything! Love it!!

[aureliuzS.F.]

You need a 100 amp for 6013 almost 2 microwave transformer welding rod and 200 amp for 7018 that's 4 microwave transformer 👍 be careful to enhale the smoke it's high in carbon dioxide😷

[rehanniazi]

dear you have 110V and my country has 220 V, so much turns for secondary coil i should make ?

[rowanballinger]

That screw driver ant gonna do much for that primary winding coating

[johnaffleck]

No; the buzzing is NOT good; and is not what you want. This is the audible evidence that you've buggered the magnetic circuit when you cut the core apart. Never cut the core.

[jaggid]

hi mate, is the secondary thick wiring is clockwise or anti clockwise
Reply

[allcomm]

I see a really VANDAL WAY to removing secondary wires. Very dangerous!

[mymumdm]

What happens when brake 1 wire on small coir

[MrClutchNinja]

Lol I bought 3 feet of 0 gauge copper at my local speaker shop

[jorgecardena]

Proviene de un mundo muy cuadrado jajajajaja

[DocHuard]

Dude, you need to stay away from electricity, you don't have a clue! 👎

[timwatson]

Do not try to make one of them the money u use u could had brought one