Measuring KOH concentration with hydrometer

[BoyntonStu]

Specific Gravity of KOH :

27% = 1.2592
28% = 1.2695
29% = 1.28
30% = 1.2905


BoyntonStu

More complete table here: http://www.ashtachemicals.com/products/kohchem.htm#sg

[computerclinic]

Good info boyntonstu...I was wondering that...

[Roland Jacques]

Thats good info . now all we have do is fine a hydrometer or Refractometer that can read that range.

[Roland Jacques]

Any luck on finding a hydrometer that can read these ranges.

I found these, I think the lower one should be OK. http://sciencekit.com/hydrometer/p/IG0023641/

[Roland Jacques]

Is it 28% by weight the Ideal concentration?
If so would 0.5 lbs of Noah or KOH and 1.0 lbs of water = 33% concentration?

[hg2]

Is it 28% by weight the Ideal concentration?
If so would 0.5 lbs of Noah or KOH and 1.0 lbs of water = 33% concentration?

28% is ideal for most dry cells,but an openbath type would overheat quickly and the amps would spike high as well.I use 33% in my dry cell which works out to over a pound of koh per gallon distilled water.
I think the hydrometer you mentioned is the same that saltwater aquarium owners use to test salt content in their tanks

[Painless]

Is the purpose of this to determine when the maximum efficient concentration has been reached?

If so, why not use a multimeter to measure the resistance across your electrolyte as KOH is added, and stop once the resistance becomes static?

[hg2]

Is the purpose of this to determine when the maximum efficient concentration has been reached?

If so, why not use a multimeter to measure the resistance across your electrolyte as KOH is added, and stop once the resistance becomes static?

I think measuring your ammount once you've determined the ideal concentration that's giving the best results would be the easiest way.If you always buy your koh from the same source it will always remain a constant.This can be done by either weight or dry measure.

[Roland Jacques]

I think the hydrometer you mentioned is the same that saltwater aquarium owners use to test salt content in their tanks

No, aquarium hydrometers are a much lower range. 1.010-1.036

[Roland Jacques]

Is the purpose of this to determine when the maximum efficient concentration has been reached?

If so, why not use a multimeter to measure the resistance across your electrolyte as KOH is added, and stop once the resistance becomes static?

Will the resistance become static?

I read somewhere the Ideal concentration is 28%, so is that where the resistance would go static? Or would be a lot higher than that with just diminishing returns?