DIY Spot Welder

[Onoff]

How safe are they and how good?

Thinking of cobbling something together as, well, I've got all the bits!

 

[daedalusminos]

What are you wanting to use it for?

 

[123hotchef]

why not we made one years ago from microwave parts

 

[slim_boy_fat]

Oooohhh, this should be good.........

 

[Onoff]

What are you wanting to use it for?

Car panels where I can.

Nobody else done it on here? Couldn't find a thread.

 

[Onoff]

Not sure if one or two ex-microwave transformers are best?

Then for the secondary coil...16mm2 earth cable would be easiest for me or 25mm2 meter tails maybe...cos I've got both!

Been needing an excuse to clear the bench!

 

[brightspark]

What are you wanting to use it for?

spot welding presumably

 

[sg66]

Not sure if one or two ex-microwave transformers are best?

Then for the secondary coil...16mm2 earth cable would be easiest for me or 25mm2 meter tails maybe...cos I've got both!

Been needing an excuse to clear the bench!

use 2 make sure they are matching, interesting to see the build and what it will weld and what current it will put out.

 

[WorkshopChris]

Not sure if one or two ex-microwave transformers are best?

Then for the secondary coil...16mm2 earth cable would be easiest for me or 25mm2 meter tails maybe...cos I've got both!

Been needing an excuse to clear the bench!

Your secondaries will probably end up needing to be much higher than 25mm.

 

[123hotchef]

We used 2 microwaves

 

[WorkshopChris]

Car panels where I can.

Nobody else done it on here? Couldn't find a thread.

Have a look at this one it might give you some ideas.
http://www.mig-welding.co.uk/forum/threads/made-a-spot-welder-out-of-a-140a-arc-welder.72825/

 

[armalites]

 

[Onoff]

Choice of 3. I've measured all the primaries. The two smaller ones are close, but are they close enough:

 

[Onoff]

Think I've some old jump leads kicking around somewhere.....

Or maybe use some 16mm2 doubled up and just be careful with the lay?

 

[Onoff]

Had the kind offer of some 50mm2 tri-rated single core tonight. Result!

Wondering if it'll be too big a dia though to go thru the trannie...about 1/2" OD I think.

 

[graffian]

I made one to spot weld the steel covers that go over land rover steering boxes.
It worked, but had to make really small spots about 2mm or less in diam.
I was given a spot welder a few day after that.

I put as much copper as would go though the hole, I packed lengths of earth lead though it and stuck some 6mm in the gaps.

 

[oddbob]

I made one using an old buzzbox transformer rather than a lightweight microwave jobby ...works as well (if not better) than the cheap Chinese thing that it replaced. link to thread

 

[Onoff]

Going to double up the two closest microwave trannies like this and see what happens!

As an aside would brass as in Commando plug pins make good electrodes?

 

[Wendelspanswick]

Going to double up the two closest microwave trannies like this and see what happens!

As an aside would brass as in Commando plug pins make good electrodes?

I would have thought the Zinc would boil off at the temperatures you'd be spot welding at, you really need Copper electrodes. How about a Copper earth rod, youd need to ensure it was a solis Copper one and not just coated steel.

 

[Agroshield]

...How about a Copper earth rod, you'd need to ensure it was a solid Copper one and not just coated steel.

I think I've seen a design somewhere that uses MIG tips as the electrodes.