DIY Spot Welder

[Onoff]

Hacksawed thru the weld to split the first trannie (vice, timber, bfo hammer) and salvaged the primary.

After I fit the new secondaries I'll need to "stick" the trannie back together. One site advocates Araldite ffs! Hardly going to guarantee continuity on the earthing!

Can't decide whether to clamp and stick /MIG weld the join or just tack each corner...

 

[DAPPH]

There used to be a cheap pistol style one that had a carbon rod in the middle , good for about 50 spots , you connected it to the buzz box arc welder's electrode holder / clamp .
You pushed the spring loaded carbon rod holder down into the job through an insulated crown by pulling the trigger .

Once contact was made & the pool formed , you eased off the pressure , the spring then took the electrode back off the metals being spotted .

Keltek is the name in my head that seems to match the device .. they were still available a couple of years ago ..

If you put Kel - Tec into Google & then look in images it's the blue & yellow one o the right side in the pictures mode

I've also had a couple of their more serious variable current & variable timer spot welders too .

 

[graffian]

Why did you cut the laminations apart?

 

[Onoff]

Why did you cut the laminations apart?

Pretty much every YouTube video on the subject does it this way. Latterly though I have found one where they cut down through the secondary then knocked the U shaped leftover out from the side.

Too late for me to do that now so I have to weld them back together.

 

[Onoff]

Any ideas how these are welded together in the factory? I read somewhere it may be by electron beam welding. It looks too smooth to have been done by hand.

 

[Onoff]

So, two transformers separated. 50mm tri rated cable hopefully delivered today. I tried fitting some 35mm earth cable - too stiff imo.

My current thoughts are to have the two trannies in a box, maybe fan cooled?

Then to maybe to bring the wires out to DINSE sockets on the panel front:

https://www.r-techwelding.co.uk/35-50mm-dinse-panel-socket/

The welding "head" to be set of "tongs" you wield like shears.

 

[weldequip]

More on the subject from Youtube

 

[Onoff]

More on the subject from Youtube

PMSL!

I've already told work I might not be in on Monday!

 

[Onoff]

Tri-rated 50mm!!!

Makes the cores look small!

 

[DAPPH]

So, two transformers separated. 50mm tri rated cable hopefully delivered today. I tried fitting some 35mm earth cable - too stiff imo.

My current thoughts are to have the two trannies in a box, maybe fan cooled?

Then to maybe to bring the wires out to DINSE sockets on the panel front:

https://www.r-techwelding.co.uk/35-50mm-dinse-panel-socket/

The welding "head" to be set of "tongs" you wield like shears.

It looks like the run of weld has been done by a fast moving hight current device such as a roller .

Thought... would this work .... set it up in a deep glass or plastic tray of water ( this is your cooling device ) . With the earth on the metal but the part to be welded just out of the water , give it a quick tig along the edges on the same side . not welding the middle . u Using a fine TIG wouldn't make a lot of heat would it ? If so how about a high speed mig pass over the edges instead .?

The transformer I recently took apart was welded down the middle like yours but off a scrapped 24 volt charger cum slave start for trucks . I ground a shallow " V " to take the weld out so I could pull the " E " shaped solenoid cores apart by hand easily & leave the windings on the plastic former . For I was after the 2 & 3 mm copper wire for our bonsai hobby .

The only reason I could think of it being welded like that down the middle was for a single pass of cheapness past a single welding head on a production line .

 

[daedalusminos]

I think you've as good as scrapped those transformer cores, what I don't understand is the video you posted showed you how to cut through the winding

 

[Onoff]

I think you've as good as scrapped those transformer cores, what I don't understand is the video you posted showed you how to cut through the winding

I'd cut the first transformer ages ago before I saw the video. I've seen as many videos hacksaw or slitting disc the weld as I have cut the core and knock it out. One lad stick welds it back together.

Wait and see I suppose!

 

[Onoff]

It looks like the run of weld has been done by a fast moving hight current device such as a roller .

Thought... would this work .... set it up in a deep glass or plastic tray of water ( this is your cooling device ) . With the earth on the metal but the part to be welded just out of the water , give it a quick tig along the edges on the same side . not welding the middle . u Using a fine TIG wouldn't make a lot of heat would it ? If so how about a high speed mig pass over the edges instead .?

The transformer I recently took apart was welded down the middle like yours but off a scrapped 24 volt charger cum slave start for trucks . I ground a shallow " V " to take the weld out so I could pull the " E " shaped solenoid cores apart by hand easily & leave the windings on the plastic former . For I was after the 2 & 3 mm copper wire for our bonsai hobby .

The only reason I could think of it being welded like that down the middle was for a single pass of cheapness past a single welding head on a production line .

MIG or stick here only!

 

[Onoff]

Bu**er!

The two, (near) matched transformer cores above aren't quite deep enough to get the original primary, the shunt cores and the 50mm sq. tri rated cable all in.

The slightly larger transformer I have would take the new assy, but I've only got the one !



Looks like I'll have to use 35mm sq!