Don’t believe everything you read!
Posted: Tue May 16, 2017 10:22 am
During my experimentation with crackle compositions, I have seen many reported formulations that, on testing, I have found not to work. Patent applications, especially those emanating from China, seem to be written with sufficiently vague specifications that the effects they claim are almost impossible to reproduce. I’ve learned not to believe any reported composition unless I know it to come from a reliable source.
Last week I spent a very pleasant morning chatting with a respected member of the professional community. Amongst other things, he told me a couple of stories about his experiences with Chinese manufacturers. In a list of the contents of imported fireworks, he noticed that copper oxide was listed more than once, each listing being accompanied by a different Chinese ideogram. He concluded that there must be something different about each of the copper oxides that appeared in the list.
On another occasion, during a visit to China, he saw an (unspecified) effect that he wanted to try, and was given the formulation, which contained copper oxide. On returning to the UK, he found he could not reproduce the effect that he had seen and got back in touch with his Chinese source. He was told he needed to use their particular type of copper oxide and they sent him a sample. He didn’t say whether it worked or not, but he did tell me that he found the ‘copper oxide’ to contain 17% potassium dichromate! He gave me a small sample and I've just run a quick and dirty solubility test on it, which confirmed the dichromate content to be about 15%.
The implication of all this seems to be that reported compositions are not only likely to be approximate in terms of the stated proportions, but may also contain unlisted ingredients. In the above example the unmentioned component is both toxic and carcinogenic, so I have to ask myself: how many other such cases exist?
Last week I spent a very pleasant morning chatting with a respected member of the professional community. Amongst other things, he told me a couple of stories about his experiences with Chinese manufacturers. In a list of the contents of imported fireworks, he noticed that copper oxide was listed more than once, each listing being accompanied by a different Chinese ideogram. He concluded that there must be something different about each of the copper oxides that appeared in the list.
On another occasion, during a visit to China, he saw an (unspecified) effect that he wanted to try, and was given the formulation, which contained copper oxide. On returning to the UK, he found he could not reproduce the effect that he had seen and got back in touch with his Chinese source. He was told he needed to use their particular type of copper oxide and they sent him a sample. He didn’t say whether it worked or not, but he did tell me that he found the ‘copper oxide’ to contain 17% potassium dichromate! He gave me a small sample and I've just run a quick and dirty solubility test on it, which confirmed the dichromate content to be about 15%.
The implication of all this seems to be that reported compositions are not only likely to be approximate in terms of the stated proportions, but may also contain unlisted ingredients. In the above example the unmentioned component is both toxic and carcinogenic, so I have to ask myself: how many other such cases exist?