Build thread: nickel strip spot welder from microwave oven transformer

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gnat
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Re: Build thread: nickel strip spot welder from microwave oven transformer

Post by gnat » Mon Apr 15, 2019 9:58 am

Heh. Yeah Caps scare the shit out of me.

I'm sure it will be unsurprising, but I was picked on heavily in middle school (Army brat that ended up in a very rural school). In shop we got to build our own florescent lights where we built the ballasts. After seeing what Caps could do, I wired a few up to one particular asshole's chair when he wasn't paying attention.

I got the shit kicked out of me for that one, but it was so worth it to see how high jumped when they went off. Bet he still has the burn marks on his ass to this day :lol:

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5chn3ll
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Re: Build thread: nickel strip spot welder from microwave oven transformer

Post by 5chn3ll » Mon Apr 15, 2019 10:25 am

Heh. I approve.

I mean, Dammit, Gnat, how terrible and irresponsible!

Understeer: You will hit the wall with the front end.
Oversteer: You will hit the wall with the rear end.
Horsepower: How hard you will hit the wall.
Torque: How far you will move the wall.

"If you see the barrier you’ve driven into, that’s understeer. If you hear yourself hitting the barrier, it’s oversteer."
-Walter Rohrl


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32wildbilly
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Re: Build thread: nickel strip spot welder from microwave oven transformer

Post by 32wildbilly » Mon Apr 15, 2019 5:17 pm

5chn3ll wrote:
Mon Apr 15, 2019 9:17 am
Now don't be ugly, as my dear old Southern grandmothers would have said.

The DIY rig is functional, but the electrode pencils I fitted it with over the weekend require running the transformer at full power, and I do not like switching that much current directly. The amount of resistance heat generated by the 0-gauge secondary winding was sufficient to split the outer layer of insulation after being plugged in for only a few seconds - I need a relay to kill power to the primary so it's not energized the entire time I'm working with the welder.

Ultimately, the mot transformer will be the one powering the spot welder, but my experimentation thus far has reinforced that I REALLY want to properly contain that much current.

I had not planned to incorporate a capacitor in the "basic" build, but after reading up on what the tail spike can do to lithium cells (spoiler: explode 'em), my "you're going to fuck up" alert system went crazy and hasn't stopped since. I have all of the parts necessary to properly build the "right" version (shunts, relays, switches), and the hum of the re-wound transformer was a great audible cue that maybe a bit more discretion was warranted.

TL;DR: Pussed out on scary version.
I was trying voice those concerns a few posts back, but...NO...Better choices but I'm still nervous for you. Hell lithium batteries don't need an outside source of electricity to burst into flames.

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32wildbilly
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Re: Build thread: nickel strip spot welder from microwave oven transformer

Post by 32wildbilly » Mon Apr 15, 2019 5:22 pm

gnat wrote:
Mon Apr 15, 2019 9:58 am
Heh. Yeah Caps scare the shit out of me.

I'm sure it will be unsurprising, but I was picked on heavily in middle school (Army brat that ended up in a very rural school). In shop we got to build our own florescent lights where we built the ballasts. After seeing what Caps could do, I wired a few up to one particular asshole's chair when he wasn't paying attention.

I got the shit kicked out of me for that one, but it was so worth it to see how high jumped when they went off. Bet he still has the burn marks on his ass to this day :lol:
Back in the day as a young electrician apprentice for the RR we would charge up small caps with a hand crank megger and play catch with them or drop them in the back pockets of old dudes overalls. Fun stuff.

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gnat
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Re: Build thread: nickel strip spot welder from microwave oven transformer

Post by gnat » Mon Apr 15, 2019 5:31 pm

Funny thing about Caps in car audio (non competition), they are exclusively used by idiots that A) don't understand electricity or B) are too cheap to properly upgrade their charging system to handle the power demand of their system.

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5chn3ll
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Re: Build thread: nickel strip spot welder from microwave oven transformer

Post by 5chn3ll » Tue Apr 16, 2019 7:27 am

Aw, Billy, I'm touched (in the head, not emotionally, but I digress). I'm being safe...shit, I didn't blow a finger off q/ the 20kv neon sign transformer in the Jacob's Ladder...this spot welder is positively benign. :D

Made a couple of test packs last night...note that these 18650s have built-in fusible links and I use them with battery control modules to keep the smoke inside...
20190416_003437.jpg
20190415_211558.jpg

Understeer: You will hit the wall with the front end.
Oversteer: You will hit the wall with the rear end.
Horsepower: How hard you will hit the wall.
Torque: How far you will move the wall.

"If you see the barrier you’ve driven into, that’s understeer. If you hear yourself hitting the barrier, it’s oversteer."
-Walter Rohrl


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gnat
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Re: Build thread: nickel strip spot welder from microwave oven transformer

Post by gnat » Tue Apr 16, 2019 8:53 am

I'm in need of some 18350 batteries for a project and I just stumbled on these.

That seems to be a most unfortunate brand name for Li-ion batteries... :lol:

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5chn3ll
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Re: Build thread: nickel strip spot welder from microwave oven transformer

Post by 5chn3ll » Tue Apr 16, 2019 9:44 am

https://batteryhookup.com is rocking 18650 and 26650 (lifepo4) cells...

I picked up a dozen or so old-stock Dell laptop batteries for about 10 bucks each on Amazon. If you can live with having to disassemble the packs and remove the existing bus bars, it's a really cheap way to get good cells - 72 never-cycled 18650 cells for $120 ain't bad.
gnat wrote:
Tue Apr 16, 2019 8:53 am
I'm in need of some 18350 batteries for a project and I just stumbled on these.

That seems to be a most unfortunate brand name for Li-ion batteries... :lol:

Understeer: You will hit the wall with the front end.
Oversteer: You will hit the wall with the rear end.
Horsepower: How hard you will hit the wall.
Torque: How far you will move the wall.

"If you see the barrier you’ve driven into, that’s understeer. If you hear yourself hitting the barrier, it’s oversteer."
-Walter Rohrl


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5chn3ll
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Re: Build thread: nickel strip spot welder from microwave oven transformer

Post by 5chn3ll » Thu Apr 18, 2019 9:11 am

Check it out! You can actually see desktop through the shit!
20190417_234100.jpg

Understeer: You will hit the wall with the front end.
Oversteer: You will hit the wall with the rear end.
Horsepower: How hard you will hit the wall.
Torque: How far you will move the wall.

"If you see the barrier you’ve driven into, that’s understeer. If you hear yourself hitting the barrier, it’s oversteer."
-Walter Rohrl


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5chn3ll
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Re: Build thread: nickel strip spot welder from microwave oven transformer

Post by 5chn3ll » Thu Apr 18, 2019 9:15 am

Gnat, check out the ridiculously overbuilt filament feed. I was going to use two old IMS bearings, but some selfish punk wanted to gold-plate his instead of donating it to the cause.

Understeer: You will hit the wall with the front end.
Oversteer: You will hit the wall with the rear end.
Horsepower: How hard you will hit the wall.
Torque: How far you will move the wall.

"If you see the barrier you’ve driven into, that’s understeer. If you hear yourself hitting the barrier, it’s oversteer."
-Walter Rohrl


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