keep it safe guys

[the fabricator]

i was welding a pair of motorcycle forks the other day, with the mig. my brother was helping me and i said for him to tack the axle brackets on. the ground clamp was either didn't have a good ground, or i was a better ground but as soon as he hit the trigger i had 130 amps at 19 volts straight across the chest. not fun.

just a reminder that these machines are dangerous, respect them

[BobL]

i was welding a pair of motorcycle forks the other day, with the mig. my brother was helping me and i said for him to tack the axle brackets on. the ground clamp was either didn't have a good ground, or i was a better ground but as soon as he hit the trigger i had 130 amps at 19 volts straight across the chest. not fun.

just a reminder that these machines are dangerous, respect them

I agree they can be very dangerous but that aside you did not receive 130 A across the chest.

130 A passing through or across your chest would fry you to a crisp, or at least cook you to a point where you would not be making your post.

In most electrical circuits, the Volts and the Resistance determine the current (irrespective of what it says on the power supply)

The human body has a nominal resistance of 1000 ohms across the chest so at 19 V a human body would pass ~19 mA . Now if you happened to be sweating even just a little your nominal resistance was less than usual so more current would have been able to pass (maybe 40 or 50mA) but it would not have been anywhere near 130 A.

At 250 v a nominal human chest will conduct ~250 mA across it which is enough to convulse a heart rhythm/muscles and eventually kill.

To get 130 A across a nominal human chest you need to be connected to 130,000 V power supply that can deliver 130 A. A spark plug coil that operates at 20,000V can't kill you because it only generates a max of a few micro amps.

[the fabricator]

i didn't know that, bit of a relief though. i just had it on maximum output and thats what the manual says its maximum is.

would it be 130 a and 19 v when welding metal because of different resistance?

[Pete F]

would it be 130 a and 19 v when welding metal because of different resistance?

Yep, the current is limited to a maximum value of whatever you set on the machine. Taken to the extreme, before you strike the arc NO current flows, yet the machine is still set to 130A. It can still give you a nasty surprise, indeed many injuries/deaths involving electricity don't involve the shock per se, but rather the reaction from the shock (eg you fall off the latter etc). It was still a good reminder to keep it safe!

Pete

[Dave J]

I remember when I was young using the stick welder in the wet changing electrodes with no gloves .:o soon made you wear them LOL

Just the other week I was mig welding something for the son and he was holding the 2 pieces in position, he soon let go when he became the earth :D

Dave

[Jekyll and Hyde]

After electrosizzling my elbow a number of times with the tig, I now put a welding glove on my (painted metal) bench to rest my filler rod arm on. For some reason, it seems to like earthing some (or all) of its juice through me instead of the earth clamp, particularly when both arms are resting on the part or the bench. The HF start in particular is good at that :U

[Bryan]

I remember as a kid hearing that a bloke up the road got electrocuted from welding on wet grass. Is that possible? I guess 'electrocuted' might have meant got a shock, but at the time I thought he was killed.

[Skew ChiDAMN!!]

As a teen I melted a few links of my watch band (Which I was wearing at the time... :doh:) when changing sticks.

I guess that's partly why I became a woodworker rather than a metalworker! :U

[Stustoys]

All sorts of things can happen with earths.
I seem to have a very low body resistance. I can get a zap of a car battery on a bad day(I guess its lucky I didn't become an electrician as I was planning lol)
Two of my stranger ones are
1. Being shocked every time I touched the tapes in the shower, although no one else in the house had a problem. Turns out the earth was bonded to the water pipe(not allowed anymore) and it was rusted so the sewer pipes were a better earth.... through me!.
2 Touching the body of my mig welder at my parents place, there would be a little shock that would fade way. Then if you let go of the welder it would build back up again. Never hear what the result of that was. The sparky just said "its stuffed your whole house needs rewiring".


The HF on tigs is a pain, I was always finding new ways to zap myself with it.

Stuart