Shelf life of formaldehyde solution vs. hexamine powder for stabilizer

[drp]

Hi,

I'm curious to know if someone knows the shelf life of formaldehyde in 10-15% methanol solution compared to hexamine in powder when either is used as part of a ECN-2/C-41 homebrew stabilizer (either then mixed with photo-flo)? I believe some of these color processing kits have hexamine already mixed in with a surfactant/photo-flo solution or have hexamine as a powder to mix. I'm aware some powder chemicals can last for several years with no significant negative effect but I wasn't sure if hexamine falls in this category or if it starts to decay, such as phenidone in powder? Similarly, if the formaldehyde/methanol solution only lasts a short time before it decays as well?

Thanks!

 

[koraks]

I understand formalin will polymerize at some point. I'm not sure if it also does this in methanol, but as I understand, it does so in water.

I've no experience with hexamine, but I don't see why it would be particularly unstable as long as it's kept dry.

starts to decay, such as phenidone in powder?

Does that decay? Seems pretty stable to me. Seems like there's an urban myth on the internet about phenidone being unstable in dry form.

BTW: note that you don't need a formalin/formaldehyde/hexamine etc. stabilizer for C41 films produced in the last 30 years or so.
For ECN2 films, it's not clear what their archival properties are. Some kind of stabilizer won't hurt. Of course, it won't hurt C41 either.