visco fuse composition, came close!

[spitfire]

Today i experimented with a new very simple formula in an attempt to copy Chinese commercial visco.

This one came close to the real deal. Although the powder had a tendency to stick to the funnel a bit, (and gave me some extra work while the machine was running) it gave me a great fuse! Made about 20 meters with it as a first test, using 100g of powder.

 

The formula:

 

KClO4......................75

Willow C...................15

Potassium Benzoate.....10

 

Yes it is over-oxidised. Needed for burning the treads of cotton yarn. Turned out to be a hidden key!

Coated the fuse with 4 layers of Nitrocellulose lacquer and cut to lengths approx. 4''

Edited May 14, 2014 by spitfire

[FlaMtnBkr]

I think most visco contains BP. It also isn't a powder but a very fine granulate so it won't get stuck in the funnel.

 

There is some newer silver core visco that is likely KClO4 and aluminum. Many people claim it is too energetic. I haven't got into mine yet to find out.

[spitfire]

I think most visco contains BP. It also isn't a powder but a very fine granulate so it won't get stuck in the funnel.

 

There is some newer silver core visco that is likely KClO4 and aluminum. Many people claim it is too energetic. I haven't got into mine yet to find out.

No. Most visco fuses do not contain straight 75/15/10 BP. I tried it more than once and it burns too slow, too weak, not hot enough and it contains not enough oxidizer to consume the threads and that leaves a lot of dross. Please note i am looking for the kind of visco used in Chinese made commercial cakes. Most shells from the orient have this fuse too, in various thickness and color. Not the fuse we buy on a roll. You are totally right about the powder used is fine granulate. I second that from my experience.

 

I am pretty sure the commercial visco contains KClO3 or at least KClO4. Conclusion based on the burning characteristics.

[taiwanluthiers]

Why not test for it? Cut apart a sample length of Chinese visco, and test it with methylene blue. It will tell you quickly if perchlorate is used (rather than nitrate). I seriously doubt they'd use potassium chlorate, the fuse would be too sensitive.

 

I think you can probably take a sample of the fuse powder and test for the chemical composition by titration...

[schroedinger]

Just for determining the oxidiser cut a few inches appart, sp, it the fuse open and leach it for a couple hours. Take the solution and divide it into three test tubesand do the ring test (iron sulpfate + sulfuric acid needed), indigo carmine and methyle blue. After that you know which oxidizer got used

[Mumbles]

Most fuse is nitrate based, but not 75/15/10. No one is going to waste perchlorate for something so trivial, when nitrate will do. You can purchase fuse powder, and it always comes with a grade. There was a lot of powder available in the US over the last year or two going for $1/lb. It was 116 fuse powder, which means it burns for 116 seconds per meter. I've read most often it contains more sulfur than conventional powder, but that's just hearsay. The tests described will tell you what oxidizer is used.

 

There is some perchlorate based visco around too.

[taiwanluthiers]

I know a lot of big fireworks companies generally keep their formula secret but the composition doesn't seem so complex that any third rate lab could analyze it with modern lab techniques to determine its composition, should someone somehow get ahold of a sample of that composition. I wonder how come nobody ever tried to bust company secret by doing that? Is it that knowing another company's secret wouldn't offer them any advantage? (for example a rival company could pay some firework crew to collect any dud or unburnt stars for analysis)

 

For example it shouldn't be difficult to determine the composition of a bp based composition, I'm sure titration could be done to find that out. However I'm sure it's not as easy to determine the specie of wood used to make the charcoal...

[spitfire]

Thanks for the replies guys, I'm pretty sure some of those tests will reveal most of the secrets. Although i wasn't planning installing a small lab just to analyze the chems used in a fuse. I know very reliable fuse can be made with very basic chems, cheaper than i mentioned. But that isn't my approach. The idea is to ''mimic'' a sort of commercial fuse, from China. And they have a LOT of different types when it comes to burning behavior! All i did so far was: watch it, try it, learn, and watch it again. For a quite some times, that is. Trial and error.

[patsroom]

Today i experimented with a new very simple formula in an attempt to copy Chinese commercial visco.

This one came close to the real deal. Although the powder had a tendency to stick to the funnel a bit, (and gave me some extra work while the machine was running) it gave me a great fuse! Made about 20 meters with it as a first test, using 100g of powder.

 

The formula:

 

KClO4......................75

Willow C...................15

Potassium Benzoate.....10

 

Yes it is over-oxidised. Needed for burning the treads of cotton yarn. Turned out to be a hidden key!

Coated the fuse with 4 layers of Nitrocellulose lacquer and cut to lengths approx. 4''

 

Today i experimented with a new very simple formula in an attempt to copy Chinese commercial visco.

This one came close to the real deal. Although the powder had a tendency to stick to the funnel a bit, (and gave me some extra work while the machine was running) it gave me a great fuse! Made about 20 meters with it as a first test, using 100g of powder.

 

The formula:

 

KClO4......................75

Willow C...................15

Potassium Benzoate.....10

 

Yes it is over-oxidised. Needed for burning the treads of cotton yarn. Turned out to be a hidden key!

Coated the fuse with 4 layers of Nitrocellulose lacquer and cut to lengths approx. 4''

Hello spitfire, would like to know if you have made any progress in fuse composition. I know there are a lot of them from just plain visco to flying fish visco. Anyways any head way?.................Pat

Edited January 27, 2015 by patsroom

[spitfire]

Yes, i did.

 

white falling leaves fuse:

 

KNO3................50

Alu dark............30

sulfur................20

 

(0.5 cm/sec)

 

easy safety fuse:

 

KClO4.............70

Willow C..........25

 

(about 0.8 cm/sec)

 

add +5% fine flake Ti for silver falling leaves fuse.

 

''aggressive'' hot safety fuse:

 

KClO4.....................70

Pot. benzoate.........30

dark al.................... 2

sulfur.......................2

 

(1 cm/sec)

 

add 5% - 7% fine flake Ti for flying fish fuse. Use short lengths. They ''swim'' a lot.

 

Another safety fuse:

 

KClO4.........................75

C willow......................10

Pot. benzoate.............10

 

(1 cm/sec)

 

Delay fuse (rather fast):

 

Fine grained BP..........75%

Powder willow BP........15%

70/30 KClO4/C.............10%

 

(about 1.5 - 2.5 cm/sec)

Edited February 3, 2015 by spitfire

[wildcherryxoxo]

It would be helpful if you had some actual burn-rates for these compositions. Im not sure how well spolette inch/s would translate into "black match", but it would be a start.

[spitfire]

I will edit my post for you with burn rate info. The burn rates are given in CM/sec, this is obtained by cutting 5 cm lengths and observed with a stopwatch. So it is not exactly accurate.