Welding truth or wind up

The first thing I do, after posting a link, is to click on my own post and check the link works.

I am starting to wonder if I am the only one :confused:
 
PabloPicasso said:
http://seaweed.thebilge.com/tohatsucarbrebuild.htm

I'm not sure how fried the batteries would end up
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Many years ago, I was servicing a car on the RAC rally and a fairly solid bit of steel needed to be welded and one of the other team members had tried and failed to get it hot enough with oxyacetylene, so he lashed something up with a welding rod and some jumper cables and managed to glue it back together

A few figures might help.

Assume 100AH battery capacity. If you don't want to damage the battery, you have 50AH available.

Using a 1/8" rod, one would want 75-125amps. Call it 100A

That gives you 30 minutes continuous welding. I imagine things would warm up a bit if you tried to do more than a minute or two at a time, but that's seems to be how welding is done.

The other complication is that welding SS or Ally seems to require a TIG or MIG welder.

I've never mastered arc welding, so take this with a pinch of salt!
 
Stemar said:
.....

I've never mastered arc welding, so take this with a pinch of salt!
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The first thing to master might be the open circuit and arc voltages, which generally want to be well north of 12V. Generally 30V or more. Yes you can weld with a few car batteries in series, but it will probably involve either a lot of skill or low standards.
The current from a car battery can be a bit uncontrolled, with a lot of instant current available as per the CCA rating!
 
vyv_cox said:
Not all that long ago many publications carried adverts for carbon arc rods and kit that were perfectly capable of brazing using a car battery.
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Indeed and when I worked in Africa I saw shade tree mechanics using batteries to that sort of stuff.
 
vyv_cox said:
Not all that long ago many publications carried adverts for carbon arc rods and kit that were perfectly capable of brazing using a car battery.
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But the practice somehaow failed to catch on. Possilby needs a lot of skill to do well?
 
Fr J Hackett said:
It's perfectly possible.

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You can see from that, the power in the arc is a long way from constant, despite matey in the video being (I hazard) fairly skilled in the art. For sure he tacked two lumps of steel together, but I'm sure he'd do neater stronger work with £150 of semi-respectable inverter welder.
 
Quite impressive. I only realised in the last 5 seconds that I could have had subtitles, which would have been useful.

Not sure why he elected to weld two brake discs together, which I would have expected to be SG iron, not metal customarily welded.
 
vyv_cox said:
Probably. somewhat akin to TIG welding. As with so many similar activities it looks so easy in the promotional videos.
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I did try it too many yeas ago to remember. The one I tried was 2 carbon electrodes that you could strike the arc and use like gas welding so you could control the heat better by removing the arc or gs flame from the work piece without killing the arc.

The difficulty I had was striking and controlling the arc in the first place before starting welding the job.
 
vyv_cox said:
Not all that long ago many publications carried adverts for carbon arc rods and kit that were perfectly capable of brazing using a car battery.
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Got one somewhere still, possibly, bought in the 60's, arc rods or carbon rod for brazing, ran off 12 volt and included a coil to provide some degree off variable control. Never got serious results though.

Brian
 
It is not supposed to be a substitute for even a cheap 240V welder, it is a get out of gaol trick to be used when nothing else is available.
 
vyv_cox said:
Not all that long ago many publications carried adverts for carbon arc rods and kit that were perfectly capable of brazing using a car battery.
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A couple of US companies sell kits. Here's one - though it wants 36V:

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http://www.trailweld.com/shop-online/the-welding-kit
 
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