Dyeing banana jacks is fairly simple, you just need a suitable dye – the jacks are nylon so a suitable fabric dye works well and soaks into the body. I use these but there are surely other brands – it is disperse dye: https://en.wikipedia.org/wiki/Disperse_dye
You really don’t need much, but it’s pretty toxic so do take care, wear gloves and a mask etc. You need to heat the mixture, I do it on an old stove in an old pan (don’t use a nice one, like I said it’s toxic stuff and will get everywhere!) I would suggest a bain-marie, but for this demo I just put them in the pan and kept stirring so they wouldn’t melt. Protect every surface, this stuff will dye most anything – forever!
Stick a pan on the stove with water in it and let it get simmering, then take a tiny amount of powder and put in a cup, then add a tiny amount of boiling water to make a paste:
The longer they are in, and the stronger your dye mixture, the shorter the time it will take (also maybe how hot it is, but don’t boil them, just a light simmer) – just keep stirring and looking at them until you get the colour you like. I have a feeling they keep getting a bit darker after you have taken them out, but I’m not sure if that is true.
Rinse and dry them, take care to get the water out the middle too.
You can mix your own colours and other things, for example I did a module with 64 jacks in an 8 x 8 grid and dyed 64, taking 8 out at a time every so often to get 8 different shades in 8 columns… enjoy yourself!
You can dye other things too: