29 replies to this topic

[Yugen-biki]

Ca(OH)2 is not replaceable with CaO. They are very different chemicaly. If you get hold of some CaO I'm looking forward to hear how it worked. :-)

[quest]

The CaO should stabilise the mixture

+
CaO + H2O --> Ca(OH)2
So the CaO will become Ca(OH)2 after the water are mixed.


I tried it with out the CaO too and had the same result as mentioned

[hashashan]

I had success with this formula but i used CuO instead of CaO.
very loud crackling sound. although when using the hydrate it just flashed upon mild heating

[paul]

I had success with this formula but i used CuO instead of CaO.
very loud crackling sound. although when using the hydrate it just flashed upon mild heating

This is quite interesting as chemical properties of CuO are completely different than of CaO ...
Did you ignite a batch of it or have you formed stars of it?

[hashashan]

I pressed micro-stars in NC lacquer

[pyrotrev]

Funny, I was just going to suggest trying CuO..... I know this as "copper thermite" and with fine Al it really does go! - never tried using dark Al (anyone got any for sale?) or making microstars with it though. Also, you sometimes get a nice little pink cloud of copper if there's enough Al around. Other transition metal oxides (with the element in a high oxidation state)might also be worth a try e.g. MnO2, V2O5 etc.

Edited by pyrotrev, 19 April 2007 - 12:40 PM.

[DeAdFX]

This question is more or less directed at the thread starter. What does ?m suppose to mean? Is that micron or mesh?

Has anybody tried using different grades of Aluminum and or Magnesium (flake/atomized/blackhead/etc)?

I wouldn't mind doing a little experimentation except I am still looking for a thiosulfate source + I have only two grades of aluminum(atomized/India) and two grades of Magnesium(granular and strips/turnings).


Thoughts on using CuO as another source of oxygen. I remember reading on sciencemadness's exotic thermite section that Iron Oxide in various states of hydration will produce some sort of a crackling noise. Prehaps we should try experimenting with Thiosulfate + various cheap/low toxicity transition metal oxides.

[pyroman89]

What is a good supply of sodium thiosulfate and what is a good price per pound? Also what is sodium thiosulfate used for, non-pyro?

Thank you

Edited by pyroman89, 06 July 2007 - 05:39 AM.

[hashashan]

Well tried to make star cores and to press those into a comet, and nothing. only 2 or 3 pops. ill try it with water.
and the thiosulfate is sold in any chem store and it supposed to be cheap
on the worst cse you can make it by boiling for several hours sodium sulfite with sulfur untill all the stochiometric sulfur had reacted

[YT2095]

it`s used in Photography as the Fixing Bath, it Dissolves any unreacted AgBr, by forming a complex of silver(I) ions and thiosulfate.

[pyromaniac303]

If only small samples are required, it has a use in aquariums although I forget what for.

[Valec]

?m should be micron, not mesh.

Edited by Valec, 07 July 2007 - 10:15 AM.

[hashashan]

600 micron????? its huge.

[Valec]

600 micron????? its huge.

Well, that's what the patent says. I think with fine powder it wouldn't crackle but flash at once, however, I haven't tried so far.
The patent mentions some more points about the size of the Mg; as I recall, it is important not to use too small particle size.

[DeAdFX]

Hmm this mixture also works Titanium aerospace alloy (90/6/4 Ti/V/Al). I tried a mix of 65% Sodium thiosulfate (hydration unknown) 25% 90/6/4 20 mesh and 10% Mg powder (200something mesh?). The mix made a bunch of rapid cracking sounds but they were not very loud. So far this stuff hasn't been super impressive. The stuff is rather difficult to ignite. I was hoping the titanium variant would have been louder...