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"Bush Welding"


Boydie
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I attended a course last weekend run by one of the local 4WD clubs, subject "Bush Welding" very informative and we were all given lots of opportunities to have a go - the source of the power supply was 4 off 12 volt batteries, in series to give a total of 12 volts and 340 amps ( 2 x 90 amp/hour wet cell and 2 x 80 amp/hour deep cells units ) what you would normally expect if two cars were traveling out in the bush.

We were given a variety of welding sticks to experiment with - no hand-grip, simply feeding the cable through a piece of water hose then winding the exposed cable around the end of the welding rod. The earth being clamped to the normal battery earth.

My attempts were feeble to say the least and resembled a splatter of bird poo but at least the metal joined, some of the guys present had obviously put in a fair degree of practice before the meeting but in any case it was a great example of what you can do with what you have in your truck, assuming of course you carry a couple of 100 amp welding rods in your spares box - which I will be doing in future . In the meanwhile I have two old spare batteries on charge so I can get some practice in !

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Good tip / life skill to learn, thanks I learnt something

sorry smart ar$% coming out.... my apologies in advance not ment to offend, batteries were wired in parallel, i.e. join all the RED (+) together and all the Black (-) together which would give you 12v and increase in ampage in the multiple of whatever the batteries are rated at.

if batteries were wired in series, they would be

...... welding clamp ---- (+) BAT (-) ------- (+) BAT (-) -------- (+) BAT (-) -------- (+) BAT (-) -------- welding electrode (if using DCEN rods, or the other way for DCEP rods), but the current would remain the same, and the voltage would be 12v+12v+12v+12v (48v....)

probably want to carry DC rods too or it may not work so well (I'm not an expert welder, sure someone else can advise on this interesting topic / skill to learn).

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It's also possible to do Bush Brazing and Bush Soldering: rip apart a few old cheap "D"-size zinc-carbon batteries and recover the carbon 'pencils' from the cores - hooked to a 12V car battery using a suitable jump-lead you can then use a pencil to generate heat enough to braze/solder things like radiators and oil-cooler/PAS pipework.

I've seen a PAS high-pressure pipe fixed this way, using a piece of metal from a food-can as a patch to repair where the pipe had been vibrating against the engine and worn a hole.

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It's also possible to do Bush Brazing and Bush Soldering: rip apart a few old cheap "D"-size zinc-carbon batteries and recover the carbon 'pencils' from the cores - hooked to a 12V car battery using a suitable jump-lead you can then use a pencil to generate heat enough to braze/solder things like radiators and oil-cooler/PAS pipework.

I've seen a PAS high-pressure pipe fixed this way, using a piece of metal from a food-can as a patch to repair where the pipe had been vibrating against the engine and worn a hole.

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If you do intend to carry rods, put them in a plastic bag as they become useless if they get damp.

And yes they were wired in parallel :)

Better still find a plastic tube and seal the end caps with tape so if you store them under the seat box and you go wadding they should remain fine until the day you need them ... Along with 4 sets of jump leads

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- the source of the power supply was 4 off 12 volt batteries, in series to give a total of 12 volts and 340 amps ( 2 x 90 amp/hour wet cell and 2 x 80 amp/hour deep cells units ) what you would normally expect if two cars were traveling out in the bush.

or.... 48 Volts and 85 amp-h. You must put them in series. 12 V won't sustain an arc. 24 or 36 can work, but not 12.

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The A-h rating of the battery has nothing to do with the amperage they provide. Any battery will put out 500 Amps easily. The only thing you can control in this setup is the voltage and you will get whatever amperage the rod will let through.

I would guess the 4 batteries would be fine for running a 3 mm rod, but too much for a 2.4 mm. I normally carry 2.4 mm rods. You can weld with 2 or three batteries then and it is easier to weld on thinner parts like the chassis. With 4 batteries and a 3 mm rod, you will have a tough time on thinner metal.

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You're all correct of course, the batteries were in series so that's 48 volts not 12 :blush:, and we used 2.5 ? (or 2.4) CIG welding rods, (I should have taken notes) but certainly not as big as 3.00mm -- the practice pieces we were given to weld were 1.5mm chassis rails off what I believe were an old Toyota - we had to first scrape off the crud with a knife to reveal clean metal.

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  • 2 months later...

As a matter of interest, many years ago, I was bought, as a present, a kit which consisted of a coil former, some heavy gauge copper wire, and an aluminium casting which made up the handle, this was the gear to create a DC welder which ran off batteries.

I wound the coil, assembled the unit and it proved to be excellent. It's action is that as you scratch the electrode, the current thro the coil withdraws the electrode into the coil, thus providing a vibrating tip, which consequently established the arc.

This was 45 years ago, at that time, I used it to carry out sheet metal repairs to my mate's father-in-law's Morris Minor, it is tremendous

Tool.

Since then, I've never had occasion to use it again, but I still have the tool, taking pride of place in my tool case.

If there is any interest I can post a photo.

Norm.

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As a matter of interest, many years ago, I was bought, as a present, a kit which consisted of a coil former, some heavy gauge copper wire, and an aluminium casting which made up the handle, this was the gear to create a DC welder which ran off batteries.

I wound the coil, assembled the unit and it proved to be excellent. It's action is that as you scratch the electrode, the current thro the coil withdraws the electrode into the coil, thus providing a vibrating tip, which consequently established the arc.

This was 45 years ago, at that time, I used it to carry out sheet metal repairs to my mate's father-in-law's Morris Minor, it is tremendous

Tool.

Since then, I've never had occasion to use it again, but I still have the tool, taking pride of place in my tool case.

If there is any interest I can post a photo.

Norm.

That would be very interesting to see...

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  • 4 months later...

The rods that were used during the teaching session were CIG "Satin Weld" 2.5mm. These seem to be the most forgiving for us learners to use :blush:

I carry my rods in a 20mm plastic tube (water pipe) with one end sealed with a glued on cap and the other has a glued on male thread fitting and a screw-on plastic cap, the total length was made to equal the rod length. It is totally water tight, easy to store and with sufficient rods packed it they don't chatter. I just use the normal jumper cables I carry in the car along with a pair of welding goggles, striking an arc is a bit "ow's-yer-father" but once it's struck and the weld is running I can see good enough through them to doa reasonable job, even so, my stick welding looks similar to pigeon carp splattered on a pristine pavement! Give me my gasless MIG any day.

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I have heard about this often but never tried it. I was told two batteries would be enough for some jobs.

However, all that aside, it brought to mind a welding kit I got from work years ago which I fitted to a Series 3 diesel. It consisted of a very decent alternator and a box which it fed. You could plug your welding cables into that box and had some control of output using the hand throttle (the 2¼ diesel being governed, that worked well). It also provided a 110 volt DC power supply, which could either then go through an AC converter or be used straight with things like a kettle.

I let that vehicle go too cheap with lots of goodies on it. I'm learning slowly not to do that!

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I tried the car battery/jump leads/ battery core to try and weld an exhaust some years ago. All I managed to achieve was to blow a damn-great hole in it :(

Les

probably no current limit, maybe try with a few 12v 55w bulbs wired together in parallel, then connected in series with the rod? to act as a load to limit the current.

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