20 replies to this topic

[dave]

hi ,

i just came across this post on the apc forum.
it might provide an alternative to chlorate/antimony sulphide e-match pyrogen.

http://www.amateurpy...0858#entry80858

it seems to be based on the following patent

http://www.freepaten...com/3793100.pdf

as i have not got any pot ferricyanide, i would be interested if anyone has or could try it.

it may have potetial for "self dippers"

any comments?

dave

[PyroCreationZ]

The topic was removed?

[#10342] We could not determine which forum this topic is in.

[dave]

The topic was removed?

ah, right............its seems to be in the HE section which you may not have access to.
not sure why they put it in that section.

if its ok to paste the relevant post here it is from the apc forum, originated by wsm :-............................................

This is my first submission in the HE section. Till now I didn't feel I had anything of note to add to the discussions here. I hope you find this offering useful.

I discussed the E-match pyrogen in the electronics section, but to ensure a degree of maturity in those who experiment with it, I decided to post the formula and process here instead of open forums.

The formula:

"Co-Precipitate" Pyrogen

58 KClO₄
37 K₃Fe(CN)₆
05 K₂Cr₂O₇

Process:

Dissolve 1g of the composition components in 5ml deionized H₂O at 100^oC, stirring until dissolved. Drop the mixture into 10ml (room temperature) isopropyl alcohol 99-100%. Vacuum filter and mix while still moist with NC lacquer to a thick syrup consistency.

A few notes are in order:

· A bit of labware is required (a hotplate/stirrer, vacuum filtration equipment, et cetera). This is no error. It is best to work quickly and safely and you need the right tools for the job to do so.

· The small quantities are also no error. The finished material, when dry, is extremely explosive and sensitive. This material is used primarily to "butter" the bridge wire, to ignite the base charge of H-3 in NC. A little goes a long way when making electric matches.

· As soon as the precipitate is filtered, wash with alcohol or acetone. While it is still moist, incorporate the mass into the nitrocellulose lacquer in a tightly closed, wide mouth jar. This keeps the material a flammable liquid until used, instead of an explosive.

· Use rubber gloves (or equivalent), a face shield, any other expedient lab safety gear, good lab hygiene (clean up spills immediately and dispose of waste promptly and appropriately), also don't forget to wash yourself thoroughly after handling this material, or its components (some are carcinogenic). The filtrate may also contain trace amounts of hazardous substances and should be handled accordingly.



If the material dries, carefully add acetone (or other compatible solvent) to dilute and stir thoroughly until of uniform consistency.

I acquired the composition in 1988 and wrote the notes above in 2000.


WSM

dave

Edited by dave, 03 July 2011 - 06:18 PM.

[PyroCreationZ]

Thx for the share Dave.
I'm indeed not in the HE section.

So far I've always used the KClO3 / Sb2S3 method and for me it works like a charm. I always dispose of leftovers though as I don't feel comfortable storing it (apart for the igniters of course).

I think it's an interesting matter but I don't have ferricyanide in my stock nor have I seen it with my suppliers.

Anyone else?

Edited by PyroCreationZ, 03 July 2011 - 08:09 PM.

[whoof]

I think it's an interesting matter but I don't have ferricyanide in my stock nor have I seen it with my suppliers.

Anyone else?

I used to use it in farmers reducer, back then it could be obtained from local chemists by signing the poisons register.
These days if you are not a reg company,-no chance, suppliers may also want to inspect premises before supply.

[pyrotrev]

Copper thiocyanate + KClO3 seems to be a promising mixture that has a lowwer impact sensitivity than Sb2S3/KClO3.

[digger]

Copper thiocyanate + KClO3 seems to be a promising mixture that has a lowwer impact sensitivity than Sb2S3/KClO3.

Seems interesting. I have a copy of the formula that a few Chinese factories use, pm me for details. There is nothing too special about their formula (if a little overcomplicated).

[dave]

Copper thiocyanate + KClO3 seems to be a promising mixture that has a lowwer impact sensitivity than Sb2S3/KClO3.

hi trev,

do you have the source for that info ?

dave

[pyrotrev]

hi trev,

do you have the source for that info ?

dave

Yes, my hammer and anvil

It was hard to get it to ignite, whereas chlorate/sulphide is a goodly bang pretty well every time.

[BrightStar]

I'm still intrigued by the pyrogen formula that Dave dug up for the Czech marketed / Chinese made e-matches:

http://www.pyrosocie...rs/page__st__15

This seems to approximate to:

Potassium Perchlorate: 2
Calcium silicide: 1
Antimony sulfide 1
Collodion: + 6%

It does seem worth investigating further.

Edited by BrightStar, 05 July 2011 - 09:04 PM.

[dave]

Yes, my hammer and anvil

It was hard to get it to ignite, whereas chlorate/sulphide is a goodly bang pretty well every time.

ah ah ...........excellent !!

dave

[Mumbles]

I'm not sure what kind of suppliers you guys have over there, but across the pond, Ferricyanide is sold for photographic purposes.

I've made the above type of mix a few times. As a safety measure, I always made the water used mildly basic by addition of a spatula tip of base. One of the ferro/ferricyanide pairs can hydrolyze a little bit and I never remember which, so better safe than sorry. I specifically was looking into it for breaking crossettes.

[dave]

I'm still intrigued by the pyrogen formula that Dave dug up for the Czech marketed / Chinese made e-matches:

http://www.pyrosocie...rs/page__st__15

This seems to approximate to:

Potassium Perchlorate: 2
Calcium silicide: 1
Antimony sulfide 1
Collodion: + 6%

It does seem worth investigating further.

the problem with that composition is where to get the calcium silicide ?

dave

[dave]

ok so i had to try it just out of curiosity, (i dont actually need to dip my own)

potassium perchlorate 60
potassium ferricyanide 40 (by the way, this easy to get if you look in the right place)

co-precipitated in ipa and washed with acetone, ........allowed to parially dry and slurried with 5%nc solution in acetone

result in a VERY FINE uniform mixture, more like paint grade pigment, ......and a nice bright yellow colour.

dipped onto blank e-match heads with 50g nichrome.........dried...........nc laquer 2 coats.............dried

this ignites easily with a nice show of flame, and nice spurt in small tube.

downside - near boiling water needs to be used to disslove the perc due to its low aqueous solubility,..........add the ferricyanide and dissolve, then dump into an excess of ipa and wash with acetone.

looks like a reliable composition, and its a nice yellow colour instead of black/grey

dave

[whoof]

What sort of impact/friction sensitivity does it have ?