Burmese thorns.

[old country chemist]

Greetings to all of you,Graham has asked me my personal opinion on the following.Interesting topic this-colouring of needles. I have always believed that an aqueous solution of 5-10per cent potassium permanaganate would do the job, but the needles would have to be left in the solution for quite some time, as the permeation into the tight bonded thorns is much more difficult than when staining triangular bamboo needles, which have many filter holes along there length, which absorbs anything-moisture mainly, but will accept doping solutions etc quite easily if left long enough. Also the permanganate solution will be "reduced" to a manganate by the keratin, and the finished product colour may look more brown than purple.I have viewed the picture of the crystals, and as they are probably old, it is difficult to tell what they are. I imagine Mercurochrome, or Sudan 3. might be suitable. Mercurochrome is water soluble, and Sudan 3 is spirit soluble. Both of these chemicals produce a red colour, depending on the concentration. As an aside, We used to sell Mercurochrome in a very dilute soloution for fin rot on goldfish-but has been banned now, I think. Sudan 3 also wants careful handling. I use it to stain a very heavy chemical called tetrabromoethane) (sg about 2.70) for producing a liquid used in sight glasses of Hobson Telegage petrol indicators. Back to the problem...Spirit solutions will soak in much more quickly than aqueous ones, and the solvent will dry quicker. I do not think there will be any harm to needles stained with such a liquid. Aqueous solutions will take much longer to permeate, and the needles will have to be left to dry much longer, as we all know what happens to needles with moisture content!! So, testing the chemical's content would be the answer, but if it is an organic product, might be difficult. Just thought-food colours, are aqueous based, and red ones are available-that might suffice. I will look into the matter more, and ask a couple of my industrial chemist pals, as I spent all my life on the pharmaceutical side. All good wishes to you chaps for a continued interesting website on machines, records, etc. I hope to rejoin the fray ere long. Alastair Murray.

[Orchorsol]

Brilliant, thanks Atastair! Sounds as though David needs to try a sample of Sudan 3.