28 replies to this topic

[Rhodri]

Cocca powder or 'brown' powder involves using a fibrous carbon source (steam charred straw for example) as a substitute for charcoal.

This type of powder was (is?) used for cannon and the like.

It's far more sensitive to friction and sparks than standard BP. I've read that it may even ignite if shaken too much in a straw bag.

My black match uses standard 75:15:10 BP with a few g's of dextrin. Keep to this and you'll have a good product.

[BigG]

No, Cocoa powder refers to specific type of sulphurless BP. I believe it originally was made with straw charcoal – although I might be wrong. You don’t need sulphur to make BP – Sulphur make the fuse ignite at lower temperature, and help the composition catch fire from the slightest spark.

Crazyjim, I would really stop experimenting with KMn04 and glycerine. It’s just not a natural fuse to start with, and falls into completely different category of pyro effects. I challenge you to find a commercial pyro manufacturer that uses this in his products.

Start with black fuse, with or without sulphur. Easy to ignite, reliable, cheap, and environment friendly . Next try Visco, and if you look for a real challenge – try to make a time fuse. Leave thermite to the end. It’s very likely that you will never need it.

BigG

Edited by BigG, 03 October 2003 - 03:26 PM.

[lord_dranack]

Start with black fuse, with or without sulphur. Easy to ignite, reliable, cheap, and environment friendly . Next try Visco, and if you look for a real challenge ? try to make a time fuse.

What is your method for making visco?

I have made some by attempting to inject a bp/dextrin paste into hollow string, the waterproofed it with NC laquer. The problem was with this method with much experimenting the longest length I made was about 3"!

[BigG]

What is your method for making visco?

I have made some by attempting to inject a bp/dextrin paste into hollow string, the waterproofed it with NC laquer. The problem was with this method with much experimenting the longest length I made was about 3"!

That is quite a good starting point for a visco.

Where did you get your string? It counts for 90% of your chance to success.

BigG

[phildunford]

Totally off the wall, but you can get a 'braided sleeving' that's used in electronics to gather abunch of wires together. if you squash it, it expands. You could fill a length of this (fine bore) with BP and then paint the outside with NC lac. This might produce am improvised bickford/visco. Might be worth a try...


You can see some at:

rs components

[Matt]

I made a visco jig a while back jut for the sake of experimentation. Basicly you need a large tube on a roller so it can spin and have 6 spools of cotton on the outside of the tube with all the strands coming through the pipe to the centre, now get some black match and hold it in the centre. Tie the ends of all the strings to the black matchand spin the tube whilst pulling the black match out. This winds the string around the black match makink a visco rip off. you will need to dip it in NC or some other laquer so the string holds its place. Thats pretty hazy but thats a rough outline of how i made it, the problem was getting the string tight because if its a bit loose then it will just quickmatch.

-Matt

[Arthur Brown]

Anyone remember the old Knitting dolly --- a wooden tube with four pins in the top used to make tubular knitted cord -- what about a funnel of BP and knit the cord round it

[Rhodri]

That's good!

I've also seen a 'spinning wheel' for forming wool balls into sizes that can be used with a 'knitting machine'.

I've used this type of machine to spin coils used in making radio LC components.

It had crossed my mind that you may be able to 'spin' some fuse with one of these.

[lord_dranack]

Big G: The string I have used was first flat bootlace with the inner taken out, and the hollow shell boiled in KNO3 solution. Now I am trying some hollow cotton string, but this dosen't have quite as tight a weave. My main problem I think was that the bp paste was either too viscous to be injected properly, or too runny to ever dry.

[BigG]

Get a candle hollow wick ? they seem to be the best. Tightly packed, and don?t let the paste out easily. Hard to get in the UK, but you can mail order from Germany or Switzerland.

BigG

[Rhodri]

This isn't Visco by any stretch of the imagination but I've had good results using straws.

Now the type I mean are not those from Burger King! The ones you need are the small type of straw that come with plastic box drinks - Ribena and the like. The best ones are from the brand 'Calypso' - small ID and often red in colour. Ram one of these into some meal BP until full.

The plastic burns and inhibits the BP from 'flashing'. These are especially good because of their strength and 'push' easily into holes made for the fuse in tubes etc. Just pop a small piece of fuse paper into the end to seal.

[leniol]

Not on the subject of fuse, BUT... According to my book of statutes, manufacture of explosives isn't a criminal offence, though if they cause harm (or the risk of harm) to people, it is. NB. There doesn't have to be an actual risk, just a theoretical risk, so doing it miles from anywhere is still not an option (according to my textbook). No doubt the regs relating to gunpowder are in some civil statute somewhere... I shall have a look sometime

[Deano 1]

Going back to igniting thermite, I just use a 3 to 4 inch length of sparkler.