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Step 4DC Stick
Weld Steel and stainless steel
Cost: $0 and up.
Another welder that's already laying in pieces in your alley, car, and garage.
see the entire DIY DC Stick Welder Instructable.
A few old batteries can deliver awesome amounts of current.
Combine 6volt and 12 volt batteries to get any voltage you need. I've never needed more than 36 volts.
I've done some really heavy welding with batteries. I've also cut holes by dipping the rods in water first.
For stainless, you can wire it electrode positive so most of the heat goes into the rod rather than the work. It's harder to strike an arc with this DC unit than the AC one. The AC unit has a higher "open-circuit voltage". Batteries are a "voltage source" and the arc is much shorter than with a "current source".
Cost: $0 and up.
Another welder that's already laying in pieces in your alley, car, and garage.
see the entire DIY DC Stick Welder Instructable.
A few old batteries can deliver awesome amounts of current.
Combine 6volt and 12 volt batteries to get any voltage you need. I've never needed more than 36 volts.
I've done some really heavy welding with batteries. I've also cut holes by dipping the rods in water first.
For stainless, you can wire it electrode positive so most of the heat goes into the rod rather than the work. It's harder to strike an arc with this DC unit than the AC one. The AC unit has a higher "open-circuit voltage". Batteries are a "voltage source" and the arc is much shorter than with a "current source".
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Here's an untested, potentially dangerous // ! \\ idea:
I would try to use (unplugged, of course) welding transformer secondary as inductor, because it can handle the high current, but beware: in that case welder secondary becomes primary, boosting the voltage in its "secondary" (i.e. in welder's primary, the winding that normally goes onto mains), which may damage it (high voltage breakdown of windings isolation), or cause lethal electric shock if anyone touches the plug ("but it wasn't plugged anywhere!").
To be sure, one should measure the voltage on welder's output when it is plugged in, and divide it with mains voltage, in order to determine transformation ratio. High voltage generated on the plug contacts when using the secondary as inductor, should be approximately battery voltage multiplied by calculated transformation ratio. If that calculated voltage exceeds mains voltage, don't do it.
If the voltage doesn't exceed it, still make sure the mains plug is isolated - make a closed, isolated box with a blind mains socket and plug the welder's mains plug into it.
"Theoretically, Hydrogen is only caused by an over-load current. So long as a rechargeable battery is close to full charged, the fed-in current (i.e., the charging current) will be converted into electrochemical energy. In fact, however, certain quantities of hydrogen and oxygen are generated in a rechargeable battery at any time, and that means both when charging and discharging - even when inoperative!"
~http://www.sonnenschein.org/Gassing.htm
They will produce gas when being discharged too, so play safe, shield them from sparks and ventilate.
I work for Exide Technologies (The world's oldest battery manufacturer!) and I can tell you we have had a few blue flame spouts from the hydrogen gas. We charge both in series and parallel, and when you have 150 batteries in a 30'x30' area, you learn to be real careful not to make sparks.
For most people, you probably wont be charging more than 3-5 batteries though, so the risk is minimal but still present. However this is why we say...
Always, ALWAYS wear safety glasses!!
Just two months ago, our newsletter featured an article on a driver who was loading junk cores at one of his stops and dropped a battery, causing acid that had pooled in the vent cap area to splash upwards and hit him in the eye. Despite rinsing it within 30-45 seconds of the incident, he did lose the vision in that eye. The acid in these batteries is the biggest risk when handling/charging them!!
The risk when charging batteries is that the gas builds pressure from accumulating inside the cells. Combustion is what you'd expect the danger to be (and it is a risk), but the hidden danger is from acid sitting in and around the vent caps (from tipping the battery, overfilling, etc.). As the pressure inside builds, it's very possible to be moving the batteries and break loose a pocket of gas that sprays acid.
Always carry batteries at waist level (not chest high), and before charging check to make sure you have not overfilled the batteries. Keep Windex (or other glass cleaner) handy, as it will neutralize and wash off acid that contacts your skin. Trust me when I say that if you've got any cuts/tears that get acid in them, you will be glad for the Windex!
That said, having charged thousands and thousands of batteries; from deep cycle, to orbitals/AGM, and enormous "Giant Lego" industrial batteries...flare ups of gas are rare, and easily avoided by having a fan to dissipate the gases, and being constantly alert and aware of where the current is at all times.
As long as you ALWAYS, ALWAYS wear safety glasses, you should have few troubles!
BUT remember that PPE is your last line of defence. Your first line of defence is to remove or control the hazard.
A problem with a lot of us is that familiarity breeds contempt.
When I began working as a carpenter the table saw scared the crap out of me. After 25 years of using one every day I ignored a basic safety principle and fed my table saw a finger.
(I am back to having a very healthy respect for safety measures.)
If these people claiming batteries only blow up when being charged maybe they can explain why so many car batteries explode when people are trying to start their engines.
The batteries in this case are being used as the source, not being charged.(no boosting involved)
Hydrogen is generated whenever there is a high current flow through the electrolyte (sulphuric acid in a car battery but large alkaline cells will produce hydrogen too).
This is true both in high amperage "quick" charging and when the batteries are under heavy load.
(A car engine being started usually draws from 80 amps to over 120 amps.)
Your welding batteries are likely supplying 70 amps or higher depending upon the welding rod you are using.
Burning heavier sticks means more current has to flow through them.
In addition to PPE the batteries should be in a ventilated battery box to prevent schrapnel if they do explode and protected from sparks.
The box does not need to be very elaborate, even an old cardboard one with a few holes in it would be a safety feature.
I am sorry, but as computers are a new thing to me I don't have any great videos or links.
There is a site called Battery Safety that has a page on this though.
http://www.rayvaughan.com/battery_safety.htm
I have blown up a couple of batteries in my life.
The first was a six volt battery in an older VW beetle. If you remember they were under the back seat. My friend had run the battery flat trying to start it. he asked for a boost and I agreed.
That battery exploded the moment I touched the second clamp to its terminals. (hence the advice to connect your ground to the car frame instead of the battery as your last connection)
Note that the battery was not been being charged but had been drawn down heavily.
It went of with a huge bang and sprayed battery parts and acid all over the inside of the bug and all over me.
It made quite an impression on a (at that time)young and inquiring mind.
I really have enjoyed reading your Instructibles, and except for this little bit about safety I have found no fault with any of them.
To repeat a question.
About how much bead will a couple batteries like you are showing allow you to run before they are unable to supply enough current or voltage?