Pyrocat-HD--Does sol. B go bad?

**Peter De Smidt** · 3-Jul-2009, 09:44

I have some Pyrocat-HD in Glycol that I bought from the P. Formulary a few years ago. Today I ran some test negatives of TMX 100 exposed at EI 50 through. I used 5ml A +5ml B + 500ml water at 75F in a Jobo CPP-2 with an Expert drum at the slowest rotation. First, I tried 7 minutes and only the slightest image showed. Next, I tried 14 minutes. This was a little better, but the neg was still way under developed. Any ideas? Might the B solution be bad? I don't have any potassium carbonate on hand, only sodium carbonate. My goal is to get suitable density to scan.

**Gem Singer** · 3-Jul-2009, 10:02

Does soln. "B" go bad?

YES, it does.

Over 1 year old. It needs replacing.

**Jrewt** · 3-Jul-2009, 10:50

I have a big bottle for A and B that have stayed good for 2 years using argon gas.

**Peter De Smidt** · 3-Jul-2009, 11:18

Thanks guys. No argon here, I'm afraid. I'll try another run with a fresh accelerator. 4 grams of sodium carbonate in 500 ml water should be the working concentration, right?

**Andre Noble** · 11-Sep-2009, 11:49

When discussing the shelf life of the stock solution of Pyrocat HD, you have to clearify if you are talking about stock solution made in water vs. made in glycol.

Pyrocat HD dissolved glycol is more stable and has a longer shelf life than when the stock sloution is made in H2O, how long Pyrocat HD in Glycol can last in stock form is the question.

**Phil** · 11-Sep-2009, 12:29

There is a post over on the APUG forum (Pyrocat – Versions and Mixing Directions - dated 7-12-09) by 'sanking' and the comments in that thread lead me to believe that, when mixed in distilled water, "Stock Solution B has indefinite shelf life."

**sanking** · 11-Sep-2009, 15:16

Originally Posted by Phil

There is a post over on the APUG forum (Pyrocat – Versions and Mixing Directions - dated 7-12-09) by 'sanking' and the comments in that thread lead me to believe that, when mixed in distilled water, "Stock Solution B has indefinite shelf life."

Stock B, a 75% sodium carbonate solution, is always mixed in water, even in the glycol kit where Solution A is mixed in glycol. My experience is that Stock B mixed in water has a shelf life of at least two or three years, which is why I suggested that it has an indefinite shelf life. I think that if it goes bad in a year or less it must have been contaminated.

Sandy King