8 quid, buy cheap buy twice or...

Alan Quay

Esteemed Pedelecer
Dec 4, 2012
2,351
1,076
Devon
Wow!!... Been watching the guys on utube melt spanners... Madness!

Just not sure on how to configure them re S or P
I don't know much about welding if I'm honest, but I do know that it's current that's key. The resistance of the work piece is not under your control (inside some limits), so voltage must be varied to get the correct current.

Since a spanner can be welded/melted at 12v I'd have thought that's in the right ballpark, but you need a way to control both voltage and duration to get a perfect weld.

Banks of batteries in P to give enough A, then those banks in S to make the required V should work.

Switching will be a problem though, as most welders use a transformer. Presumably they switch on the HV side, where current is much lower. The same effect you want on your workpeice will happen in your switch contacts if you're not careful.

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Danidl

Esteemed Pedelecer
Sep 29, 2016
8,610
12,256
73
Ireland
I don't know much about welding if I'm honest, but I do know that it's current that's key. The resistance of the work piece is not under your control (inside some limits), so voltage must be varied to get the correct current.

Since a spanner can be welded/melted at 12v I'd have thought that's in the right ballpark, but you need a way to control both voltage and duration to get a perfect weld.

Banks of batteries in P to give enough A, then those banks in S to make the required V should work.

Switching will be a problem though, as most welders use a transformer. Presumably they switch on the HV side, where current is much lower. The same effect you want on your workpeice will happen in your switch contacts if you're not careful.

Sent from my HTC 10 using Tapatalk
There is a major thread on YouTube about making spot welders and other devices from the transformer in a microwave oven. ... These are readily available in the local recycling centre and are educational to strip down. The trafo is typically 700 to 900watt, so is really powerful. The idea is to remove the entire secondary winding the thin wiring, which is otherwise used to make the high voltage, and replace it with a few 3 to5 turns of thick wire. As a new low voltage secondary The microswitch from the doorway assy can be used to switch on the mains power 100 of amps at very small voltages are therefore available across the secondary .......
 
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