Which is the best ratio between KOH in 1litre water?

You might get a laugh out of this... I got some time this afternoon to mix some electrolyte. Not thinking much about it.... I poured precisely 5oz of KOH into 50oz of H2O for a 10% mixture into a 2liter coke bottle (yes it was empty and cleaned prior)... Anyway, it darn near melted the bottom of the bottle. I got scared and put it outside until things cooled down. Just laughing at myself now...

Also as things were cooling down and I was looking this up I found this bit of information on the web regarding KOH -vs- NaOH: "Potassium hydroxide is preferred over sodium hydroxide because its solutions are more conductive." - found it here: http://en.wikipedia.org/wiki/Potassium_hydroxide

That is why I mix my elite in a glass messuring cup and only small amount at a time. Mixing in plastic is not good and can leach the plastic properties into your elite.

"D"

Use stainless steel to mix your electrolyte in. Pyrex or oven safe glass will work but I prefer stainless steel. Mix it slowly so you do not create to much heat. Do not breath in the fumes. Be careful!!! Percent is by weight not by volume. It is easier to use a hydrometer just make sure you measure at room temperature or compensate for the temperature when using a hydrometer. (Charts and links have been posted before) Like Darrel says electrolyte will leach stuff out of the plastic. Never store it in plastic it will start leaking over time and your results will not be as good if stored in plastic. I use large (10 Gallon) stainless steel kettles that are used in beer making. There are smaller (30 qt), thinner and cheaper ones available. The large ones are NOT cheap but easy to use with a spigot and site glass to see how much is in the container. Even the spigot is stainless. You can add a spigot to the cheap ones too. I mix max strength using DD (double distilled) water and then use it with DD water to dilute it to the strength I want to use. Winter gets max strength and the rest of the time a week mixture. I make my own distilled water or just re-distill commercial distilled water if I am in a hurry which does not happen very often.

The reason KOH is considered better is because it is more conductive at max concentration than NaOH at max. Industry uses more NaOH because it is cheaper. I use NaOH because it is readily available in just about all local markets places. In my testing in my setup it seems to maintain its concentration longer than KOH. I have no explanation for this and is just what I have found and might only apply to my system.

KOH seems to show up more in the vapor of the gas leaving the reactor and that maybe why the concentration is lost. I have noticed that the loss is even more when higher voltage is being applied. D

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Originally Posted by TimCollins

You might get a laugh out of this... I got some time this afternoon to mix some electrolyte. Not thinking much about it.... I poured precisely 5oz of KOH into 50oz of H2O for a 10% mixture into a 2liter coke bottle (yes it was empty and cleaned prior)... Anyway, it darn near melted the bottom of the bottle. I got scared and put it outside until things cooled down. Just laughing at myself now...

Also as things were cooling down and I was looking this up I found this bit of information on the web regarding KOH -vs- NaOH: "Potassium hydroxide is preferred over sodium hydroxide because its solutions are more conductive." - found it here: http://en.wikipedia.org/wiki/Potassium_hydroxide

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A minor point.
Using 5oz to 50oz is about 9% not 10%. You have to look at the total finished weight (55oz in this case) to calculate %.
A 10% mix would be 5oz KOH (10% of total) to 45oz Distilled water (90% of total).;)

In order to get the correct active area, you have to subtract the gasket area, port, and dead gas to prevent any electrolysis the top of the board space, so it most likely is less.