8 replies to this topic

[novacat14]

Ok so i know everyone here has probably made the old smoke b**bs with sugar and kno3, and some have made them by melting the chemicals together, i was wondering is there a way to make the melted comp. less tacky? It is hard to work with, and solidifys very fast. I was wondering if there was a way to make the process easier, or to add a something to help the comp be more workable.

Thanks for everything guys!

[alany]

Add a little glycerine, it gives you more working time.

[tdpyro]

You could also try replacing the sugar (sucrose) with dextrose, this can be easily found at most food stores. It solidifies alot slower and also has a lower melting point, making it easier and safer to mix. I think that it is slightly less hydroscopic too. However, I havent done any comparison tests, so i do not know if it produces as much smoke as sucrose.

[novacat14]

Add a little glycerine, it gives you more working time.

Would the glycerine have any adverse effects on the comp?

[alany]

Would the glycerine have any adverse effects on the comp?

No, in fact it can make poorly integrated candy-style propellants burn better.

It is used all the time in edible candy too.

[Themolehole_9876]

Ive tried a simple composition given to me by a friend, the standard 60/40 but then add 25% of the total.. in this case 25g of wax. then milling it all together into a fine powder. works great.. pumps out stacks of smoke only thing is you have to put it in a tin with a hole only for the smoke to get out and try to eliminate a visable flame. if you get what i mean.. lol but yeah it works great for me! very easy too, no melting

[Phoenix]

Here's an interesting and vaguely topical little discovery I've made recently; I've always had a bit of a problem with rockets bursting, and I wanted a rocket fuel that would be tougher and less likely to crack, and a little more forgiving in terms of nozzle geometry etc. Since I suspect a lot of the initial "tail" the rocket produces ends up on the ground under the launch tube, and what you see streaking out behind it is mostly caused by the solid portion of fuel grain, I thought that using a sugar propellant for the hollow section of the fuel grain might solve some of my problems, and provided the solid section above was something interesting, it shouldn?t diminish the effect too much.

Anyway, to get to the point, I ball milled 70:30 nitrate/sugar rocket propellant, and it burned fine. To make it extra hard (when rammed - casting it's never appealed) I added a dash (<2%, I expect) of stearin, and then allowed it to mill until this was evenly distributed throughout it. (As this could be called an experimental composition, I might point out here that it was a small batch and my mill is located such that it could pop without doing any damage to anything). Once this was done, I tried lighting some of the powder, and it would burn briskly whilst a torch flame was on it, but would go out immediately once the flame was removed. Unperturbed, I made a "spollette" of it and tried that. Wouldn't ignite. I made various other attempts to get the stuff to work, including pressing a choked tube full of it with a prime of normal rocket fuel - still nothing doing. It seems that the 1 or 2% of stearin I added has thoroughly fireproofed the stuff. I?m sure it would burn if the pressure was high enough, but I suspect that the results of using it in firework rockets could be rather embarrassing. I might be able to salvage the small batch I made by adding a bit of BP or something to it in order to keep it lit. Worst-case scenario, the tomatoes can have it...

[paul]

Hm, I really wonder about that!

I wonder becuase even 60/40 KNO3/Sugar with 25% stearine added to it, as mentioned in the post above you, burns just fine.

My only explanation is the 7/3 mix... Once, I tried all mixes from 5/5 up to 8/2... At 7/3 it is quite hard to get a propperly burning mix without a ballmill... But anyway, this mix is heavily over-oxidized, so the added stearin should at least make it not burning even worse.

As a conclusion I can say that it seems quite strange to me...

[Phoenix]

Yeah, that sounds plausible - I used a 70:30 ratio because I'd assumed that the 65:35 formula was already sugar heavy for ease of casting (to be honest I didn't check that - being lazy) and I was going to be adding a very oxygen hungry fuel to it.

That said, the plain sugar/nitrate mix did definitely burn before the stearin was added. Never mind - it holds together well enough without stearin.