Electrical Engineering - Make your own mig with batteries and inductor ?

Author

Make your own mig with batteries and inductor ?

Mike

2007-03-18, 9:25 am

Hi chaps,

Looking to do some mig welding but only have single phase power which
means I wont be able to generate the currents needed for aluminium 3" plate.

ie. Somewhere around the 150 to 200Amp secondary.

So I'm wondering if anyone has made a mig from a set of car batteries
and what size/spec inductor you would use to generate an arc ?

--
Regards
Mike
* VK/VL Commodore FuseRails that wont warp or melt with fuse failure indication
and now with auto 10-15 min timer for engine illumination option.
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Rick

2007-03-18, 1:25 pm

"Mike" <erazmus@iinet.net.au> wrote in message
news:45fd3606$0$17585$5a62ac22@per-qv1-newsreader-01.iinet.net.au...
> Hi chaps,
>
> Looking to do some mig welding but only have single phase power which
> means I wont be able to generate the currents needed for aluminium 3" plate.
>
> ie. Somewhere around the 150 to 200Amp secondary.
>
> So I'm wondering if anyone has made a mig from a set of car batteries
> and what size/spec inductor you would use to generate an arc ?
>
>
>
> --
> Regards
> Mike

Might find some ideas here...

http://www.readywelder.com/

Palindrome

2007-03-18, 1:25 pm

Mike wrote:
> Hi chaps,
>
> Looking to do some mig welding but only have single phase power which
> means I wont be able to generate the currents needed for aluminium 3" plate.
>
> ie. Somewhere around the 150 to 200Amp secondary.
>
> So I'm wondering if anyone has made a mig from a set of car batteries
> and what size/spec inductor you would use to generate an arc ?
>
>
>

The inductor won't help overmuch. You need a sustained voltage to keep
the arc going and the inductor won't provide that. If you have enough
volts to sustain the arc, you have enough to strike it.

If you are trying to use less battery voltage than will sustain a
reasonable length of arc, then you can use a small hv invertor with a
secondary electrode to sustain it. The sort used to light oil-fired
burners works quite well - I've used one with 24v of battery to arc weld
using coated electrodes. It's easier than using a regular arc welder as
the arc strikes before the rod actually touches the metal.

You could get an inverter-type mig/tig set and bring out the primary DC
connections - and connect those to your chain of deep cycle battteries -
not car batteries. eg http://www.trojan-battery.com/

However, be very very careful. There is shedloads of power there to kill
you thousands of times over and burn your place down in an instant. Plus
the usual fire risks of batteries charging. Plus welding using lots and
lots of watts - that's why welders need 3 phase supplies. Your bank of
batteries is going to empty very quickly.

Can't you just hire a suitable generator/ mobile welder or use gas?

I presume that you mean 3" wide bar and not 3" thick plate?

I prefer gas welding - easier to use a gas welder to heat a mug of soup..

--
Sue

Mike

2007-03-19, 3:25 am

In article <_2cLh.13839$tD2.13561@newsread1.news.pas.earthlink.net>, notta@goodone.com says...

[color=darkred]
>Might find some ideas here...
>
>http://www.readywelder.com/

Interesting device, though rather expensive for the amount of hardware in
it, there is a local supplier at a small airport about 30Kms away, have sent
them email but no reply as yet. Definitely worth taking a closer look at but
the price seems awfully high for the parts, I guess they still havent
recovered their R&D or exploiting the uniquess of it for as long as they
can...

--
Regards
Mike
* VK/VL Commodore FuseRails that wont warp or melt with fuse failure indication
and now with auto 10-15 min timer for engine illumination option.
* VN, VP, VR Models with relay holder in progress.
* Twin Tyres to suit most sedans, trikes and motorcycle sidecars
http://niche.iinet.net.au

Mike

2007-03-19, 3:25 am

In article <8odLh.360727$gM1.229670@fe04.news.easynews.com>, me9@privacy.net says...

>The inductor won't help overmuch. You need a sustained voltage to keep
>the arc going and the inductor won't provide that. If you have enough
>volts to sustain the arc, you have enough to strike it.

Sorry I wasnt detailed enough, ie For an inductor to give more voltage
than the batteries would supply it would need an interruptor, so that
V=Ldi/dt could do its thing. Saw this site http://www.readywelder.com
and guessed the little control box was prob a fast high current switch
at maybe 1KHz and using the inductance of the cables given the current
is high...

>If you are trying to use less battery voltage than will sustain a
>reasonable length of arc, then you can use a small hv invertor with a
>secondary electrode to sustain it. The sort used to light oil-fired
>burners works quite well - I've used one with 24v of battery to arc weld
>using coated electrodes. It's easier than using a regular arc welder as
>the arc strikes before the rod actually touches the metal.

mmmm, Thats another idea and I like the potential for it to ease the
starting of the arc. Have a regular arc welder but not happy with using
it for the Aluminium manifold setup I want to make a proof of concept

>You could get an inverter-type mig/tig set and bring out the primary DC
>connections - and connect those to your chain of deep cycle battteries -
>not car batteries. eg http://www.trojan-battery.com/

I can get lots of cheap car batteries and dont care if they die but then
the time and effort carrying them around may not be worth it. I actually
do have a 3-phase mig but not in working condition, when I get it fixed
I guess I could get an alternate transformer for it.
ie. Leave the old one in place, get a companion transformer for single
phase that would be at the max of its rating for a single phase supply,
and just rewire the secondary into the 3-phase unit and the correct feed
for the controls etc.

>However, be very very careful. There is shedloads of power there to kill
>you thousands of times over and burn your place down in an instant. Plus
>the usual fire risks of batteries charging. Plus welding using lots and
>lots of watts - that's why welders need 3 phase supplies. Your bank of
>batteries is going to empty very quickly.

Yeah there is a lot of potential for bangs, not least of which is the
ease with which H2 explodes, and its propensity to stick to static
surfaces all over the place and not rise like it does in Hollywood.

Anyone that wants to use H2 with all its safety and energy density issues
for terrestrial transport has never done a thermodynamic analysis

>Can't you just hire a suitable generator/ mobile welder or use gas?
>
>I presume that you mean 3" wide bar and not 3" thick plate?
>
>I prefer gas welding - easier to use a gas welder to heat a mug of soup..

Other option was going to be a single phase motor to 3-phase alternator,
I recall a few units around years ago. All in one, ie Windings on same
rotor/stator - no coupling to another spinning part etc.
But for that price I can probably get a small s/h 3-phase gen set.

Re plate, yeah meant to say 0.3" and lots of pipe, have done steel mig
but never ally mig so will need to experiment a heap, especially if I
want to make an aluminium coffee cup... mmmm Start with a dish and layer
it up around the top edge each time I want to rewarm it ;)

thanks

--
Regards
Mike
* VK/VL Commodore FuseRails that wont warp or melt with fuse failure indication
and now with auto 10-15 min timer for engine illumination option.
* VN, VP, VR Models with relay holder in progress.
* Twin Tyres to suit most sedans, trikes and motorcycle sidecars
http://niche.iinet.net.au

Rick

2007-03-19, 3:25 am

"Mike" <erazmus@iinet.net.au> wrote in message
news:45fdf88b$0$17588$5a62ac22@per-qv1-newsreader-01.iinet.net.au...
> In article <_2cLh.13839$tD2.13561@newsread1.news.pas.earthlink.net>, notta@goodone.com
says...
>
>
>
> Interesting device, though rather expensive for the amount of hardware in
> it, there is a local supplier at a small airport about 30Kms away, have sent
> them email but no reply as yet. Definitely worth taking a closer look at but
> the price seems awfully high for the parts, I guess they still havent
> recovered their R&D or exploiting the uniquess of it for as long as they
> can...
>
>
> --
> Regards
> Mike
> * VK/VL Commodore FuseRails that wont warp or melt with fuse failure indication
> and now with auto 10-15 min timer for engine illumination option.
> * VN, VP, VR Models with relay holder in progress.
> * Twin Tyres to suit most sedans, trikes and motorcycle sidecars
> http://niche.iinet.net.au

Also try asking at sci.engr.joining.welding.....

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