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Micro-Weld carbon torch 1A

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Chris Shelton01/07/2018 12:52:33
92 forum posts
46 photos

img_0369.jpgimg_0371.jpgimg_0370.jpgHello All,

I picked up this unit at a boot sale this morning, was going to use the case to house the electronics and motor for power feed on my milling machine.

But looking inside I think it might be useable as a spot welder for lithium battery connections, or for resistance soldering.

The AC output voltage can be varied from 1V to 6V.

Would like to know what the originalimg_0374.jpg torch/hand piece used with it would consist of.

Can't find any info on it having searched the web.

Speedy Builder501/07/2018 14:43:54
2107 forum posts
146 photos

Looks like a very small contact brazing kit. The "Torch" would hold a stick of carbon with a pencil point - probably 1/4" diameter and protruding from the torch by about 1". The steel to be brazed would be earthed and the carbon rod touched onto the steel component (probably no more than 1/32" thick. Special bronze filler rod would be added to the 'weld puddle' , melt and form a brazed joint. At 1 amp, it may only be enough to solder and not even braze. These are the twin carbon torches, but its not man enough for them:-

Ian Parkin01/07/2018 15:03:56
839 forum posts
202 photos

I would think that 1A is the model number rather than output current.

It looks like it could output 80+ amps

SillyOldDuffer01/07/2018 15:16:37
6325 forum posts
1387 photos

Been a couple of threads recently about Resistance Soldering Units and how hard it is to find a suitable transformer. You've got one! It might even be usable as an RSU without modification; is there anyway of controlling it with a foot-switch?

It might be worth a few bob, the units are very handy for soldering delicate plates - don't destroy it for the box.


Michael Gilligan01/07/2018 18:17:30
16366 forum posts
714 photos


Chris Shelton04/07/2018 14:00:48
92 forum posts
46 photos

Thank you all for taking the time to reply, I will not use it for the case, instead will look at fitting a foot switch to control it, but did not like the idea of switching the mains with a foot switch.

And I think it would have to be quite a substantial relay, to switch the output from the transformer.

Michael G. Thank you for the link, it looks as if the one shown has an extra din plug fitted to the front of it, probably for a foot switch.

David George 105/07/2018 08:11:26
1335 forum posts
447 photos

You can get a solid state relay to switch large amperage in a small package very useful for this type of application.


SillyOldDuffer05/07/2018 11:43:28
6325 forum posts
1387 photos

As long as you get a suitable foot-switch there's no problem controlling one of these from the mains side. The unit is only 180W (less than 1A) which is low-end.

For use in a workshop one of these would do, other brands available:


Speedy Builder505/07/2018 12:12:14
2107 forum posts
146 photos

Yes, you would switch the mains side, not the high amp O/p side. Remember, there is little need to switch on/off as the circuit is only made when the carbon touches the ground side of the output. I used the same process to restore the bodywork on a 1932 Austin 7 - probably used 6Kg of bronze weld rod in the process. Its great as you can braze rusty metal without cleaning it up first, but the joints are left hard and not very malleable. You do need goggles suitable to this sort of braze/welding and there is plenty of UV, so best to cover up (sunburn in mid winter !!).

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