Waxy residue in PC-TEA

[MikeSeb]

I mixed a 500-mL batch of PC-TEA today--not my first one--using 400mL TEA slightly warmed, then adding proportional amounts of ascorbic acid and phenidone, followed by additional TEA to make 500mL solution. I noticed, as always, that the AA was tough to dissolve, and even with warming and vigorous stirring it did not dissolve completely. I had dissolved the phenidone in a few mL of isopropyl alcohol which made it easier to dissolve.

After 8 hrs or so I noticed there was a waxy precipitate in the bottle as if the blizzard of AA had precipitated partially; I put the whole batch in the microwave and gradually heated it and stirred it. Other than turning the TEA a rich amber color, it also seemed to dissolve most of the precipitate.

Is this precipitate indeed undissolved AA? Anything about what I describe to give anyone pause? Any reason to think I've ruined the batch? Suggestions to make the process go easier? I love the developer, but it's a pain to mix.

 

[juan]

After reading a number of threads on a number of forums about PC-TEA, I am considering mixing my next batch by heating some propelyne glycol - about 20% of the total volume and dissolving the P and C in that, then topping off with warm TEA. Other threads indicate the chemicals dissolve more easily in the hot glycol - no need for the phenidone in alcohol - and that the TEA needs only be warm. The glycol is also supposed to help make the solution more pourable.

Don't have any real clue about your precipitate, but it seems that if you got it all into solution, and it stayed in solution, the developer should work. The old Fred Picker maxim comes into play - Try It.
juan

 

[gainer]

TEA does turn color with heating, even with nothing else in it, according to Dow. I favor these days using just enough TEA to neutralize the AA, add a little water, heat moderately and stir, then add warm glycol and phenidone. 38 ml of TEA and about the same amount of water are enough for 50 grams of AA. This mixture will make a grainy syrup but should easily dissolve when you add the propylene glycol. This stock is about neutral and so needs a second stock which has the advantage that it can be anything your heart fancies and in any amount. Diluting it with TEA and water 1:1:50 brings you pretty close to the original PC-TEA.