5 replies to this topic

[Arthur Brown]

Just found this in a formulary compiled in the 70s

Candle comp
KNO3 _________ 34
S_________________7
Charcoal 24 mesh__15
Charcoal 16 mesh __3
Charcoal 12 Mesh __3
Dextrin ____________1

Just shows how mesh size and distribution matters

[paul]

I don?t get the point. Really. There are many compositions with give wonderfull effects that use only one type of charcoal (one mesh.size)

And as there is no composition to compare the above with, there is no way to show

how mesh size and distribution matters

or did I get something wrong?! please correct me then.

[miniskinny]

Well, mesh plays importance in many ways, especially concerning KNO3 and charcoal. Airfloat is used in gunpowder, and the larger meshes are used for better fountains and tiger tails. Though I must agree the slight changes in meshes in this formula seems a little too precise for my taste...

[Richard H]

In the above I suspect the courser grades of charcoal are largely for visual spark effect as the delay burns in the tube, producing showers of sparks between each star ejection.

[Arthur Brown]

I posted that as an example! There are several posts on here saying why doesnt my.......... and all attempts at remote divining of the answer are lost when the questioner cannot say critical things about the mix.

[BigG]

Let me explain in a bit more details Richard answer. Roman candles are made today in two principle ways. In the first a fuse is laid along the entire inside of the tube, igniting each lift charge as it burns down. The lift charges and the stars that they lift are separated by felt, clay or compacted wood shavings. In the second; more traditional way, each lift and star are separated by a CANDLE COPOSITION ? basically a slower burning composition that burn like a fountain until the next star is reached ? so in the traditional way we will put some lift charge in the tube, followed the star it will lift, followed by candle composition (compacted), followed by lift powder, followed by star, followed by candle composition (compacted) etc, etc, etc When we light this ? the candle composition burn giving a nice fountain effect - until it reach the lift ? which bring the star out and ignite the next bit of candle composition ? which burns until it reach the next star and so one until all the candle composition burn and all the star lifted.

The Candle composition that Arthur provided and not composition of stars ? it the composition that provide the delay in the candle. It need to be not slow nor fast, burn cleanly and provide a pleasant effect as a fountain. The different charcoal size means that we get different size of sparks ? and a nicer effect. Of course ? one need to experiment. Commercial manufacturers sometimes hold three to ten type of wood charcoal, each graded to different sizes ? so Paul, it does matter. It also matter for the more serious hobbyist which builds 50 fountains just to see which grade combination gives the best effect. It does not matter if all you want is to get the device to work ? for this any fine wood mesh will do.