HACKED!: Microwave Transformer becomes a High Current Transformer

WARNING: This project uses mains voltage. Do not replicate it!

In this episode of HACKED! I want to create a weld for my electric longboard. But I do not have a welding machine. That is why I will repurpose an old transformer from a microwave into a high current transformer that should be capable of doing the job.

Music:
2011 Lookalike by Bartlebeats

[jebthereb]

I’m a little late to the game.

Welder here. Stick welding needs about 34 volts to work properly.

[Afrotechmods]

Aluminum is really hard to weld - recommend trying iron or steel for your next attempts

[boshooda]

WARNING: Microwave ovens contain high voltage capacitors. Even when unplugged, these can kill you. DO NOT TAKE APART A MICROWAVE UNLESS YOU KNOW EXACTLY WHAT YOU ARE DOING!

[nickbruns]

You need at least 30-36 volts to do any arc welding. You can stick weld at as low as 60-70 amps, but you need the voltage to get the arc going and maintain it. I think you'd need 2 transformers for it. Maybe re-visit this project later? Your videos are very informative!

[Reversefilms]

I'm a video and this welder kills me

[MrDylman]

those aluminum electrodes are for Tig welding, used as filler rod. which is completely different from stick welding

[dgoss]

"someone who knows how to weld" is the key here. It took me ages to learn how to lay a proper bead and I was using a very nice welder. Welding is one of the few things that require a developed skill in addition to knowledge.

[foureyedchick]

Dear Scott: You mentioned that the output voltage of the 2nd design is about 8 volts. My late husband was an auto mechanic and in his shop the arc welders ran around 24 volts. I am suggesting a 24v design. Hope this helps.

[GAASP]

3:22 we are going to make a SHUNT (any electroboom viewers?)

[GonzoGonschi]

be aware to discharge the high voltage capacitor before you start messing inside the microwave. also the magnetron may contain beryllium oxide which is very dangerous once you break it apart and inhale dust of it. only mess with microwaves if you know what you are doing.

[chadbarrett]

A store bought welder would be safer and more effective but where is the fun in that?

[iordachej]

Very rare video of failures. That saves a ton of time for others who want to do the same. And this is a valuable lesson. Thanks for posting.

[abdul-q-khan]

One of the best about Great Scott he doesn't make fake videos.

[skrublord]

why do u end the vid so fast me wanna see coin getting rekt

[Azoooro]

Trying to weld Aluminium without welding experience with a homemade welder is VERY ambitious, as others have pointed out (not that that's necessarily a bad thing). I'm not a professional welder, but I have a little bit of experience with WIG/TIG welding and the theory behind it, so I wanted to point out some things I noticed (some of which others have already pointed out, but I'll repeat them for completeness).
First off, even experienced Welders often don't enjoy welding Aluminium. This is due to the oxide layer which forms on the surface and has a higher melting point than the unoxidized Aluminium below it. As a result, you'll have a puddle of molten Aluminium, between the surface layers, which will simply run away once the surface melts. This is normally alleviated by preparing the surface with a wire brush or similar, removing the oxide layer (which will form again very quickly, so timing is key there). Another trick is welding with AC (normally, TIG welding is DC with the Workpiece as the Anode, because the part receiving the electrons gets hotter), which will help breaking up the oxide layer with the changing current direction. The third problem you have would be the missing inert atmosphere, which would prevent new oxide from forming during the welding and keep the weld pool stable.

On general welding: I have no experience with this personally, because my Inverter has a HF-Starter, but as far as I know, starting an arc without HF is quite skill intensive ("Streichzündung" in german). I think you have to touch the electrode to the workpiece for the current to flow, and then lift it at the right time for the arc to form (but as I said, no experience). Also, for a stable arc, you need to roughly maintain the distance between workpiece and electrode, which can be pretty hard if your electrode melts off (like it does with stick welding) and damn near impossible if it quickly melts away (like your aluminium filler wire). This problem is increased by AC welding, because as mentioned above, the part receiving electrons gets hot.

With all this being said, my recommendation would be a design change to steel. If you put a steel sleeve over the axle and fasten it with the screw, it should have no problem taking the load. Then you can weld your motor mount (made out of steel) to this steel sleeve.

Keep up making these awesome videos!

PS: If you happen to live in southern germany and want to practice welding with a commercial inverter, you can shoot me a pm.

[brianj]

I would recommend you put some more turns on the secondary. Aim for around 26 volts AC output. Then use a full bridge rectifier and a filter capacitor of sufficient rating to convert the ac power to a smoothly rectified DC output, which is almost mandatory for aluminum and recommended for steel.

[binaryglitch]

I love that you don't just cherry pick the projects that work out to post.

[michaeludovicic]

See what Photonicinduction has to offer on transformers.

[RiaRadioFMHD]

Welding requires at least a minimum of 24 volts. The weld is created by the amperage but also the the potential difference between the the electrodes.
It will also help reduce loss if you keep the secondary coil as close to the core as possible.

[YourGoddamRight]

Fuck me i was waiting for the skateboard to be welded but nope.