a quick search didn't yield any answers to this so here goes:

i'm familiar with the sodium carbonate wash of the non-polar solvent (pre-cyrstalization) for STB teks, to remove any residual lye. My question is, without a pH meter, how do I get the sodium carbonate solution to pH ~8.5 as recommended in Entropymaster's tek? Basically I'm looking for a ratio of mL naphtha: mL water: g sodium carbonate

i'm assuming that getting an exact pH here isn't a very big deal, since all anyone ever seems to say about it is "make a dilute sodium carbonate solution", but I still want to have a ballpark idea of what I should be doing.

thanks for your time.

Making a solution of 50-100g of sodium carbonate per litre water per 100-200ml of naphtha should not leave you disappointed.

Hope that helps!

are you serious, inf? wow... SWIM just puts a pinch (unmeasured, but definitely way under 50g) of it in maybe 100ml water for washing 100-200ml pulls.. Just goes to show its no exact science, as long as the water is slightly basic it will wash it out

SWIM knows. 50-100g is probably an overkill! A pinch is basically enough, yet one cannot add too much sodium carbonate. It is safer to advise people to add more just in case (in case one's water source is too acidic or too hard or whatever). More It won't harm at all.

But thanks for bringing this up!

There is a thread that offers some crude pH calculators for acids and bases dissolved in just water.

I always used a saturated solution 1ml H2O:1ml Solvent.

in the recent months i have learned alot about water chemistry. where i live the water is already 8.1/8.2 region. adding just a pinch i would say would be more than enough. at my work i tell people to put pounds of this tuff in there pool just raise it tiny amounts. it is VERY potent stuff compared to sodium carbonate etc. just figured id add my two cents on this one my friend is about to wash some naptha so i figured id some research for him so he doesnt mess any thing up. thanks everyone