Showing posts with label welder. Show all posts
Showing posts with label welder. Show all posts

Wednesday, September 30, 2009

Electric Arc Welder

Having just published a post, I was just reviewing my projects to-do list...

After many hours of on-line searching I've found that whilst it's possible to build an arc welder it's neither easy nor cheap!

to buy one from a shop costs about £100.
to buy one from a car boot sale costs about £10.

I've bought one at a car boot sale.
I plan to convert this to also be useful as a TIG welder as well. (though this won't be useful for aluminium unless I can design a HF start circuit).

Thursday, November 30, 2006

The Things I do for a laugh...

It's been a while since I posted anything, and as anyone who actually read this may have guessed...

that's because I havn't made anything...

well that's not strictly true, I havn't made anything worth writing about...

I have started a few projects though.
for instance...
I'm making a tab welder, it's very simple, heres the theory.

welding is a simple process, you take two metals, heat them till they melt, when they have melted the mix, as they cool they harden, attached to each other...

a tab welding welds thins strips of metal together by momentarily melting them with some very high current, they are normally used to join plates to batteries when making a battery pack.

the long and the short of it is that you charge a capacitor, then you discharge it through the surfaces that you want to weld, the capacitor discharges very quickly, and because the resistance of the materials is so low, a large amount of current is draw from the capacitor, large current = large heat, large heat = metal melted and fused...

simple huh?

Anyone who is still confused should google "spot welding",

well... when I say capacitor, I actually mean capacitor bank. I'm using 33,000 uF caps, and plan to have about 200 in my cap bank, simply because I have a regular supply of junk equipment that use these and I can take them out prior to disposal...

it's all about keeping the costs down...
at the moment, (with only 30 caps), I can attach a single strand of copper wire to a slot blanking plate from a computer case...

so I'm hoping that a couple of hundred caps will enable me to weld things from the reasonably thick, to the very thin... altering the amount (time) of current available with the amount I charge the cap bank to.