Comments on: How-to: Build your own spot welder

By: mp

mp — Sat, 17 Sep 2011 08:34:54 +0000

i have several transformers laying around, but none of them are MOTs :(
what is special about MOT? could i strip off secondary winding from any other transformer and have a spot welder?
i can see that one of my transformers has primary wound around the core and the secondary right on the primary.
will any stepdown transformer fit the job?
of course with sufficient power.

By: mk

mk — Sun, 07 Aug 2011 13:13:13 +0000

A microwave can’t act as a cylioscope?

By: mk

mk — Sun, 07 Aug 2011 12:50:56 +0000

got any adobe software or early century california pottery, or best of all a heat press?

or $80 cash and a favor, and with that comes a recreation of ANYTHING you want done in photoshop/printing.

By: mk

mk — Sun, 07 Aug 2011 12:43:55 +0000

just say “squirming coil”…..or alternator…..it’s what creates the electrical charge.

By: Abhishek

Abhishek — Sat, 09 Jul 2011 05:56:12 +0000

Hey guy . Tell me man that as transformer’s size increases the primary winding decreases or increases. And i have a confusion isn’t dat the primary winding made of thin wire having input from wall socket

By: Nathan Zadoks

Nathan Zadoks — Wed, 08 Jun 2011 21:04:15 +0000

@Harley Watkins: Wrong kind of spot welder.
This’ll kill or seriously maim you if you use it with a lithium batttery.
For batteries you have to use a capacitive discharge spot welder.
They are more complicated and more expensive but cheaper than the surgery you’d need otherwise.

– Nathan

By: Harley Watkins

Harley Watkins — Wed, 08 Jun 2011 16:16:11 +0000

How would you modify this setup to accomodate say a LiPo 18650/26650 cell, where you would be spot welding nickel tabs to the teminal ends of the cells?

I want to build my own battery for an e-bike, and really want to spot weld it.

Thanks

By: theodore

theodore — Wed, 04 May 2011 20:55:43 +0000

Man to think I was going to give some tard 500 bucks for a battery welder when I can just make one for free? I’m the tard!

By: Edenweze victor.N

Edenweze victor.N — Tue, 05 Apr 2011 16:38:53 +0000

Pls how can one produce a spot welder bigger than this with a dimension of (600*300)mm?, i am using it as a school project.pls help me out!!

By: Louis

Louis — Thu, 03 Feb 2011 16:58:47 +0000

FANTASTIC!! Article, and great follow-up questions. I too am an old fart that has spent many moons tinkering with electronics. It’s great to see there are so many tinkerers still out there. I can hardly wait to find myself a microwave oven that someone wants to throw away.

By: mrmicrowave

mrmicrowave — Sun, 16 Jan 2011 21:11:48 +0000

Look for everyone who critizies this guy, its a HOME BUILT device that will proberly see light work, what it should be built like and how it is built is down to how “anal” the individual is in building of the spot welder, wood is great as its easy to work with and strong, it only conducts current when wet or has a few thousand volts shoved up it, in this welder it will NEVER see that, TV cabinets were made of wood and these had 25Kv generated inside ! I agree maybe earthing the transfomer core is a good idea as if the primery windings cooks and melt plastic core former there is a danger core will become live, other than than I built mine in the same way, used a hacksaw to remove the seconderys and did NOT damage the pri in doing this, infact there is about 1/2 inch seperation between the pri and sec so you would have to be sawing at full speed and not paying attention to cut into pri, if you want a welder that has everthing go buy one !

By: mike

mike — Sat, 04 Dec 2010 14:55:47 +0000

Cute! I used old MOT’s for other things. Thanks for the idea. Might want to keep the turns in line with the primary. I liked the guy who was concerned about shock off a 3 volt secondary! Anyway, going to try this myself for my next amp project. Wind a 30 amp filament xmfr off those old MOT’s. Build a case using a spot welder you suggested…

By: Bill

Bill — Sat, 12 Jun 2010 01:32:03 +0000

Hey Guys! First, I am a Professional Engineer, near retirement so I go back to the days where a kid’s first radio was homemade quartz crystal and the only stations were AM. There was NO TV station in my hometown till I was 6. OK, I am an old fart. So I love this, I have traveled much of the world, teaching 3rd world folks how to do things to get/make drinking water with the tools and supplies at hand.

This is a rare and lost state of mind, to find your own way around a need, in the USofA. So I compliment the author and all who are excited at the Idea.

I ran into a medical doc who could not get artificial limbs for amputee children in India. They had been carving strap-on limbs out of wood but these are heavy for kids. He realize there were piles of plastic water and soda bottles around. He now very cheaply purchases solvent, melts the plastic and dips cloth strips in and saturates it in the gummy mix. This is used to hand mold hollow plastic limbs that can be painted to match complexion. These are stronger and lighter than the wood and almost as good as the expensive fiberglass imports.

This project reminds me of many 3rd world shops that I have seen and compliments the desire to do it yourself. KUDOS

For the fella interested in spot welding panels, go to http://www.hackaday.com/209/06/23/how_to_build_your_own_spot_welder

By: Toby Cubbin

Toby Cubbin — Fri, 28 May 2010 00:35:44 +0000

I understand most of it but I have a couple questions about wiring.

1) How can one tell by looking at the mot, which is primary and which is secondary? Will secondary have more turns with a smaller wire gauge?

2) Wiring to a home outlet: As simple as soldering a spare extension cord to the positive and ground wires of the primary coil? Or is it more advanced?

Also, what size breaker are we looking at? Could I, perchance, hook this thing up in my garage to a standard 120v outlet after unplugging my drill battery charger, or is it more advanced?

By: Nathan Zadoks

Nathan Zadoks — Mon, 10 May 2010 05:32:17 +0000

Thanks for the explanation :)