Shelf Life and fluctuating Temperatures

[steve]

I have mixed up some dyes and they have been stored in my garage where temperatures have varied from the 30s F to the low 70s F. I understand that dyes in solution keep longer if stored at cooler temperatures--but do flucutating temperatures have any particular impact--or should I assume they will have the shelf life that they would have at the mean of the temperatures that they have been exposed to?

Steve

[pburch]

I think it's safe to assume that it's just cummulative, the dyes being able to last so many hours at 70°, or almost twice as many hours at 52°, etc. You'd need calculus to actually calculate it in detail. But if they're good for three weeks at 70°, and they've been at 50° for half of each day and 70° for the other half of each day, you might estimate that they'd last for four and a half weeks.

It's not the arithmetic mean of the temperatures they've been exposed to. It doesn't matter how many hours they've spent frozen solid, if they've spent one day in the car at 150°F+.

Paula

[steve]

You'd need calculus to actually calculate it in detail.

It's not the arithmetic mean of the temperatures they've been exposed to. It doesn't matter how many hours they've spent frozen solid, if they've spent one day in the car at 150°F+.

Paula

Ah--fond memories of integrals--I loved calculus--alas, it's been decades!

Your analysis makes sense! Since my temperatures reach neither freezing, nor 150F, the mean is probably not a horrible number to work with. Probably good for 3 weeks!

[Sevda]

I had an instructor that said they could keep for up to 2 years. She does a lot of work for the movies and is a teacher in textiles (dying and breakdown ) at a local college. She was using the dylon pucks though, not sure if they make a difference.

[pburch]

It does make a big difference what kind of dye you are using. Some dyes last a lot longer than others.

Dylon makes a number of different kinds of dye. Their Multi Purpose dye is just all-purpose dye, which lasts forever but is never very good even when fresh. Dylon Cold Water Dye and Dylon Washing Machine Dye are both mostly Drimarene K dye. This is a good fiber reactive dye, like Procion MX dye, but it is less reactive than Procion MX dye. This means that it lasts longer when dissolved in water, but it prefers warmer temperatures to react with the fabric.

Dylon Permanent Dye contains the same Drimarene K dyes as Dylon Cold Water Dye and Dylon Washing Machine Dye, but because, in this case, the dye has soda ash or TSP added already, the dye is good for only an hour after you add water.

Paula