Hi George L,
I remember using a 'welding kit' made to run from a 12v car battery
in the early sixties.
It was a strange contraption, and i have never seen one since then,
it had a crudely made solenoid in the rod-holding handle,
which made the rod pull back about a sixteenth of an inch or so
when contact was made, this solenoid being in series with the rod
also stopped the current.
This contraption would sort of vibrate quite firmly in use, and by
varying the pressure gently on the rod quite an acceptable arc could
be made, I never did much with it, I only got it as something to
play around with, i did manage to 'stick' a few bits of metal with
it, but i soon lost interest.
It would only manage very thin welding rods, i think they used to be
called 'sixteens' or 'sixteen gauge'.
I think i still have it somewhere, it's the sort of thing i would
hang on to, if i come across it i will post some pictures.
As for electric Aluminium welding, unless you're prepared to spend
time and money you won't get far. There are two usual methods of Ally
welding ... 'TIG' and 'MIG'
TIG involves using the arc rather like a flame, producing the arc with
one hand, and adding the weld material rod with the other hand.
Takes a lot of practice and experience in differentiating between
many different grades and types of aluminium, which often look very
similar, but which not all co-here to each other very well. This also
affects the choice of rod material, which may or may not need to be
the same.
MIG to my mind is a lot easier, you use a reel of ally wire feed,
again the operator has to decide if the parts and the wire are
compatible. You can buy a kit to convert a normal MIG set-up to use
it for aluminium welding. It a bit of a hassle, but it works ok.
************************
Batteries do give off hydrogen, charging or discharging, and yes it
can go bang. The most usual source of ignition in my opinion is poor
or loose connections on the battery terminals. In many years of
battery charging and discharging and swapping on vehicles and jump
starting with car batteries, i have only twice ever seen a 'pop' of
a flame from a car battery. But i can imagine that if it occurred
in some awkward place, maybe where it could have built up then it
could be just as serious as any explosion, with acid thrown in for
fun.
Ever since i saw that 'pop' which was a yellow flame, i knew what it
was and i have made sure that i charge batteries in the open air,
adequately ventilated. And since then i have never looked directly
down into the cells when fiddling with the hydrometer, something i
did used to do before. Now i tend to turn off the charger when doing
anything much to the battery. It made me a bit careful.
Having said that, i think it is pretty rare.
Best of luck with your welding project, John