10 replies to this topic

[tdpyro]

What would be a good prime for ammonium perchlorate based stars without using AP itself? Also I do not have potassium dichromate which many prime compositions recommend for using with a potassium perchlorate.
Thanks for any help.

[sizzle]

How about a sulphur-less black powder?

[Mumbles]

That wont work because it has KNO3 in it. KNO3 reacts with the AP forming Ammonium Nitrate, and if you get this, the stars will never dry. In David Bleser's Round Stars and shells, he gives an AP prime composition. I have never tried it, but I will share it here.

Potassium Perchlorate - 75
Red Gum - 12
Charcoal Airfloat - 9
Dextrin - 4

[sizzle]

That wont work because it has KNO3 in it. KNO3 reacts with the AP forming Ammonium Nitrate, and if you get this, the stars will never dry.

Ah, trust me to think of the incompatible formulas

[Frozentech]

That wont work because it has KNO3 in it. KNO3 reacts with the AP forming Ammonium Nitrate, and if you get this, the stars will never dry. In David Bleser's Round Stars and shells, he gives an AP prime composition. I have never tried it, but I will share it here.

Potassium Perchlorate - 75
Red Gum - 12
Charcoal Airfloat - 9
Dextrin - 4

Yep, that's the one to use with AP. If you add in a bit of NC 10-15% lacquer to bind it, you could then do a final step of priming over it with BP.

[Yugen-biki]

Nitrate of barium or sodium are coimpatible with NH4ClO4. "BP" made with one of them will work.
(I'm not 100% sure about the Ba(NO3)2. Can some one confirm?)

[fishy1]

Nitrate of barium or sodium are coimpatible with NH4ClO4. "BP" made with one of them will work.
(I'm not 100% sure about the Ba(NO3)2. Can some one confirm?)

NaNO3 is hydroscopic.

[tdpyro]

Thanks Mumbles that is the kind of thing I was looking for, I will give it a go.
Yugen-biki I am trying to steer clear of barium salts , due to their toxicity.
Does anyone know why potassium dichromate is often used in compositions similar to the prime suggested by Mumbles?

[Mumbles]

Barium Nitrate is fine to use I believe. There is a reason, I just don't know it right now. Anyway Potassium Dichromate is often used because it catalyses the decomposition of perchlorates. This becomes useful if the prime is relativly cool burning. The lower ignition temperature will work on the surface where there is the perchlorate-dichromate interaction, and the heat from the surface will ignite the rest of the star.

Side note, but do you think this dichromate-perchlorate interaction is why dichromate coating of Mg doesn't work for Mg-AP compositions? The activation energy is lowered so much that it reacts at room temp, or the AP just decomposes

[Frozentech]

Barium Nitrate is fine to use I believe. There is a reason, I just don't know it right now. Anyway Potassium Dichromate is often used because it catalyses the decomposition of perchlorates. This becomes useful if the prime is relativly cool burning. The lower ignition temperature will work on the surface where there is the perchlorate-dichromate interaction, and the heat from the surface will ignite the rest of the star.

Side note, but do you think this dichromate-perchlorate interaction is why dichromate coating of Mg doesn't work for Mg-AP compositions? The activation energy is lowered so much that it reacts at room temp, or the AP just decomposes

Whoops ! Dichromate treatment of Mg is no good with AP ? I had decided to try treating MgAl for use with ammonium perc after I recently had some reaction in a violet lance comp. Shimizu specified that dichromate was the treatment that wouldn't react with AP, but I've not tried it yet.

[Mumbles]

It could be. Maybe I am thinking of MgAl dichromate treatment not working well. Either Mg, or MgAl has no single treatment that is very good for protection from AP.