7 replies to this topic

[Gecko123]

Hi
I was thinking of making some of the Bleser green magnesium stars (barium nitrate based) and have seen that using strontium nitrate would produce red. Anyway I was wondering if using say sodium nitrate (yellow) and copper nitrate (blue) and other nitrates for different colours would work.
Thanks 😀

[maxman]

I'm not sure on the specific comp you refer too but bear in mind that strontium nitrate and sodium nitrate are hydroscopic. The point being magnesium and water don't like each other and could become very dangerous if wet.

 

Perhaps you could post the comp?

 

Rod

[Gecko123]

This is the one I was thinking of making ( its of of pyrodata.com)

55 Barium nitrate
18 Magnesium (100-200 mesh)
12 Parlon
15 PVC

[maxman]

Do you press them dry? or what binder / solvent will you use?

 

Rod

[Gecko123]

All it says on the website is to roll them and bind with acetone

[maxman]

Yes bind with acetone only! NOT water. Keep water and moisture away from stars containing magnesium. The parlon helps protect the magnesium. Bleser #7 red mag is 55 strontium nitrate 7 PVC 10 parlon 28  100-200 mesh magnesium so seems ok to use strontium in place of barium nitrate.
 
#9 yellow mag is  45 potassium perchlorate  13 cryolite  30 magnesium 10 PVC 2 charcoal
 
I think I would stay away from sodium nitrate where magnesium is used. Though yellow sunrise looks interesting to make maybe
 
55 Sodium nitrate 5 charcoal 10 sulphur 25 MgAl  5 dextrin see sweet dreams rocket

 

It is possible to dry press 55.5 sodium nitrate 17 magnesium 27.5 PVC as per Lancaster but you need to treat the magnesium with linseed oil first and they have a limited shelf life.

 

Rod

[Gecko123]

Thanks rod big help those stars look really good

[RichardH08]

Nobody has yet commented on the suggestion that copper nitrate could be substituted, to give a blue colour.

 

That is not a good idea for several reasons. Firstly, copper nitrate crystals contain water of crystallisation that can’t be removed by heating; the copper nitrate will start to decompose before the water is driven off. Secondly, copper nitrate is deliquescent – given the opportunity, it will absorb water from the atmosphere until it turns into a solution. Finally, and most importantly, a mixture of a reactive metal like magnesium with copper nitrate is chemically unstable; given the slightest trace of moisture, they will react. In the worst case, the reaction might generate enough heat for the mix to spontaneously ignite.

 

This type of reaction can occur with any copper compound that is soluble in water, which is why most blue star compositions use insoluble substances such as copper metal, copper oxide, basic copper carbonate or Paris Green (copper acetoarsenite). There are a few older formulations that include copper sulphate but I wouldn’t care to try them.