7 replies to this topic

[BPBR]

Today I was preparing a smoke b**b mix,and when it was almost already it suddenly ignited,I've lose some head hair(it was a little wet,if it wasn't it be much worse ).In what temperature should I melt it without the risk of accidentally ignition?
PS:Btw do anyone know in what approximately temperature black powder ignites?I want to put a fuse on the smoke b**b and I have to wait until it's cold enough to be safe to insert the fuse.

[pymp]

Today I was preparing a smoke b**b mix,and when it was almost already it suddenly ignited,I've lose some head hair(it was a little wet,if it wasn't it be much worse ).In what temperature should I melt it without the risk of accidentally ignition?
PS:Btw do anyone know in what approximately temperature black powder ignites?I want to put a fuse on the smoke b**b and I have to wait until it's cold enough to be safe to insert the fuse.

In the past I have used a fairly low-medium flame on a camping stove. As long as you stir it constantly to prevent the mixture near the bottom burning, and you don't try to heat too much at once, you should be OK.

[RegimentalPyro]

I'm very sorry to hear about your mishap BPBR, and I hope your hair grows back soon.

Please PLEASE use an electric hotplate on a long extension lead if heating in future. Having a bare flame next to a pyro comp is risky in the extreme.

When making smoke comps which contain sugar, you should use a high temp thermometer [ask in your local cooks shop for a sugar thermometer - they are not expensive]. This allows you to keep your heating controlled and at a safe level. Make sure your temperature does not rise more than 10 deg above the melting point of the KNO3 sugar. [KNO3 melts at 333degC, sugar at 186degC].

BP needs a higher temp to ignite - The KNO3 only decomposes above 600deg.....

Whilst pure KNO3 only decomposes above 600deg, the sulphur in BP lowers the ignition temp to abour 330degC

[Asteroid]

BP doesnt nessecarily have a higher ignition temp. Sulphur spontaneously ignites iirc at around 300C, the temperature of one of my aga hotplates, it gives off enough energy to start the rest of the comp. It acts to lower the ignition temp of bp.

[Caramanos2000]

I do this almost everyday in an electric skiller or rice pot. I have never had ignition with this method. I stick to around 380-400F. I did get ignition in an electric toaster oven because the mix came in direct contact with the element.

[Mumbles]

I would not approach anywhere near the melting point of KNO3. The sugar is the only thing that should be melting. Solid oxidisers are one thing, but combine hot liquid oxidisers and fuels together, and you're asking for trouble. Caramanos is around the MP of sugar.

I think the ignition point of BP is around 350 or so.


[edit]
This site lists it at 626F. Thats 330 C. I was close if it's right.

http://www.fireworks...com/ignite.html

Edited by Mumbles, 21 January 2007 - 09:39 PM.

[BPBR]

Thanks for replies I will try not to exceed the melting point of the sugar online,I think that melting the sugar and KNO3 at 330°C is not a safe thing to do as Mumbles said.

[BigBang]

The other thing you can do of course, is not to melt it at all. You will get similar (but not quite as good) results if you just mix the comp and leave it as a powder. Put it in a thin walled paper tube, and away you go. This eliminates all risk of combustion.