[jmagurany]

     I recently built a very crude rust removal bucket and have a 10 amp car battery charger with 6v-12v selection ( Its an oldy but goody). I have been using Morton table salt to make the water electrolytic which seems to be working but, I intend to put a lot of tools through this process and I need to be more accurate with my ratios of salt to water so the cost can stay low and the process remain effective enough to warrant its' continued use.
     So, again for clarity, I am asking for equations that would allow me to mix precise ratios of salt to water in order to make it conduct electricity freely. If more illustration of my equipment and setup is needed I can provide but I don't need a total rethink of my device, just equations. What I will give up front is; I want to put 10 amps at 6 to 12 volts through alloy steel tools, some are chromed and others might be carbon steel, I am using uniodized salt and tap water cause its cheap, I am willing to switch if it's cost effective (say to sodium carbonate), I use a five gallon bucket with iron and tin structure as anode to surround tools, I am doing this sometimes inside my enclosed sun-porch (and I have pets), and I have retained some memory of the mathematics and chemistry I studied in college. 
     Thanks if you can help and let me know if i need to give more information. I would just again say that I know my setup isn't perfect in its fundamental stage but I really want to focus on the chemical solution right now and not the electronics or anything else though I'm sure some of that requires discussing. Unless of course something sounds horribly wrong.
                                                                                                   Joe

[Borek]

As far as I can tell one thing is off in your approach. Total current is a function of not only solution conductivity, but also surface/shape of the electrodes. That is turn means there is no way to prepare a solution of the "one size fits all" type.

I would not waste time on calculations, I would try experimental approach.

[jmagurany]

As far as I can tell one thing is off in your approach. Total current is a function of not only solution conductivity, but also surface/shape of the electrodes. That is turn means there is no way to prepare a solution of the "one size fits all" type.

I would not waste time on calculations, I would try experimental approach.

Well I managed to find a voltmeter/ammeter and that helped me gauge the best results. Oddly enough I prefer using the salt MUCH more than anything else. It is safe (unlike the potash lye my G/F uses to make he soaps) and is cheap (compared to either Sodium Bicarbonate/Carbonate) so i can use much more of it which in turn increases the amount of current the solution can conduct. Plus I can see my tool easier in the solution unlike the sodas. I still wish i had a pen and paper mathematics way to derive the best formula, only so I didn't feel so much like a guy on his porch pouring chemicals into a 5 gallon bucket. If I had equations people who saw my set up would certainly feel more at ease... I think?

[Borek]

If you want digits and formulas you can always try to find the experimental dependence between current and concentration for your particular setup. Then you will be able to calculate how much salt to add. But first step is finding the relationship experimentally.