slow burning brick formula?

[Mephistopheles]

I searched on the forums, yet to no avail.... I'm looking for a formula that I could press into somewhat firm bricks, that'll burn slowly, yet kinda hot... (nowhere near as hot as thermite though) similar to those "snakes" firework novelties, but much larger.

It doesn't really matter if it produces smoke or not. Any suggestions?

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Remembering to capitalize the first letters of your sentences is a suggestion. ;)

[Bert]

Look at the thread http://www.roguesci.org/theforum/pyrotechnics/504-flash-powder-castable-plaster-incendiaries.html?highlight=cast+plaster Cast plaster/Aluminum may suit. Sorry about the double post-

[knowledgehungry]

I'm not sure if this is what you are looking for but a while back I knew someone who made a mixture of KMnO4, Silicon Caulk(100%) and Al. The result was a long, hot and bright burn with a large amount of smoke produced. I do not remember the ratios used but it wasn't that hard to figure out for the guy.

[FireFly]

What are you trying to do with it and exactly how hot do you want it to burn? Perhaps you could simply make an extra large "snake" or use a brick of Mg. Although Mg burns fast in its powdered form with a strong oxidizer, it burns rather slow on its own and does produce a great deal of heat. With dextrin you should be able to make it into brick form. In addition, adding a reducing agent might produce a little more heat. Just some ideas. Good luck.

Here's one more thing that might help from "Thermite & Incendiaries". It lists a couple of thermic igniter compositions that are supposed to produce a great deal of heat to ignite thermites. Please keep in mind I've never tried it out for myself and therefore don't know how well it works. Furthermore, it doesn't state the burn rate in the article.

Comp. 1
Barium nitrate 40
Barium peroxide 40
Magnesium 200-325 mesh 20
Sodium bicarbonate (additional) 1

[Alexires]

Due to the sad deprived country that I live in, I have never seen a "snake" (firework, not animal), but I don't understand why you couldn't use a KNO3 + Sugar mix and press it with a hydraulic press? Adjust the ratios for rate of burn and temperature, and with enough force, I'm sure you could turn it into a "brick".
Or use home made blackpowder. Incomplete ratios for slow combustion and press into a brick.

Thats my two cents anyway.

[lucas]

Potassium nitate with sugar can be melted very easily to be cast into any reasonable shape. The powdered ingredients are mixed and then melted slowly over mild electric heat until molten with a thick consistency. 60% KNO3 40% sugar works well and is easy to cast. Increasing to 65% KNO3 gives higher temperature and burn rate. I have cast 65/35 into rocket propellant grains with great success. The final grain is hard but brittle.
50/50 is very easy to cast and is acceptable if temperature isn't critial. Dextrose gives a slower burning mixture and is easier to cast as it melts at a lower temperature and caramalises less readily. It is also less hygroscopic. The sugar is best if dried before use.

Preety much anything that can be safely pressed is ideal, but using a binder is not hard. For black powder and many other mixtures, a bit of shellac dissolved in metho can be used to bind a pyrotechnic mixture into a slower burning solid grain.

I'd recommend finding a mixture containing aluminium or magnesium if you want high temps, and avoid chlorates. Maybe some carbon, aluminium, potassium nitrate, bound by shellac. Those ingredients are all fairly easy obtain and work with. Potassium permanganate cant be bound by this method. The ethanol is oxidised by the permanganate and the mixture ruined.

[Bean_Doodle]

Lucas, are your ratios in weight or volume?
I know weight is the standard but when I tried that, I ended up with way to much sugar and poorly burning mix.

[munas]

I have tried that but by volume... I use 4 spoons of sugar, and 6 spoons of potassium or sodium nitrate. It works very good and I get fast burning.

The problem to me is that it makes a lot of smoke.

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:rolleyes: :D

NBK