Lead Styphnate as primer to Picric Acid (Questions)

[peppovsky]

Hello. I'm new here, and the only reason I haven't posted this in the water cooler is... well, it is closed for now :-P

I have recently successfully synthesized some Styphnic Acid, has access to MgO and Pb(NO3)2, and I'm planning on making Lead Styphnate. I'm also planning to synthesize some Picric acid, since it should be relatively easier to make then Styphnic Acid. I have some experience in the area of pyrotechnics - so long distance electric ignition is not a problem, except maybe for the fact that it is for igniting pyro mixes, and I'm not sure if it would detonate Lead Styphnate by itself (Although the temperature itself is more then enough).

So here are my questions:

My plan is as following: press 4-5 gr. of Picric Acid to a 1 cm diameter tube, then on top of it press (carefully, of course ;-) ) 7-10 gr. of Lead Styphnate. Insert a pyrotechnic electric igniter to the LS area (one that burns quickly at over 400 degrees centigrade), and seal the cap.
Do you think that will detonate the Picric acid? Will it at least detonate the Lead Styphnate? Should I use larger amounts of primer Styphnate? Should I let the igniter ignite a flash mix that will, hopefully, ignite the LS? ...or am I looking at it all the wrong way, and I should use static electricity to ignite the LS in the first place?

[nbk2000]

Questins about primary explosives, like LS, don't go in the HE section, but here.

Second, use proper smiley codes.

Regarding the question, you'd be using way too much LS!

100 milligrams of LS to 2 grams of PA would be more than adequate, assuming proper pressing and crystal size of the materials. All of which you can find by UTFSE. ;)

[Bluebanshee]

I think that with a 1 cm diameter tube you may well be getting a bit close to (or below) the critical diameter for picric acid in which case it will not detonate unless it is seriously over driven, I dont't know the critical diameter offhand but could probably look it up...

why not try to make a bit more picric acid and less lead styphnate. then you can use a larger diameter charge, I agree that the quantity of the primary should be greatly reduced from your original idea of 7-10 grams, generally its best to use as little primary as possible, maybe go for half a gram or so in order to ensure you give the picric acid a big enough kick.

I think the lead styphnate will detonate fine from the igniter.

one other concern is that you need some way to tell for definite that your material did detonate. just hearing a bang isnt enough as that could be just due to the primary or it might be caused by a fast burn of the picric acid leading to pressure burst of your tube. A reliable way to tell whether or not you get true detonation is to place a witness plate in direct contact with your main charge. this would normally be a block of metal such as steel, aluminium or copper, but pretty much any tough solid material will do. If your charge detonates, you will get a dent in the witness plate.

Good luck

[peppovsky]

First of all, I apologize for putting the thread in the wrong forums, my mistake, won't happen again. Second, I found contradicted info while searching this subject, for example one source stated that LS is a "poor primer" and the other said it's the primer most commonly used today, and so on. So I came to the forums with a specific question ;) (Thanks for the info and answers, btw)

About the charge itself - I will use much less primary, as you advised me, and will try to find a larger then 1 cm diameter tube for that (shouldn't be a problem). Should I use Copper or Aluminum tube? maybe something else is preferred? And the last question for now - I thought of closing the ends of the tube with epoxy cure (e.g. P.S.I.'s "repair quick"). Is it generally OK, or do you advise on using something else, like real metal cap screwed on the tube for example?

[hereno]

It IS a piss poor initiator, while it also IS the most common, theres a reason its mixed with lead azide in detonators. Lead styphnate provides the flame sensitivity and lead azide the initiating strength.

Lead styphnate is commonly also used in priming compositions for firearm cartridges, thus it is a good "primer" in that sense, but certainly not in the initiating a high explosive sense.

Use the 10g detonator, you'll need it :P

[Microtek]

As hereno says, LS does have very low initiating power. Regarding the tube size, you don't need 10 mm ID. The critical diameter of picric acid in a steel sleeve is 4 mm, so 6-8 mm is easily enough ( I've used 5 mm ID thin brass tubing with no problems ). If you would like to use a metallic tube, you must use the detonator within a few days after preparing it, otherwise you risk the formation of sensitive picrates. These may be able to set off the cap prematurely. If I were you, I would use a plastic tube instead ( although it would need to be slightly larger; 10 mm ID would be plenty ).
As for the primer, I think you should go to the trouble of preparing something better than LS or the peroxides. If you can buy or synthesize an ionic nitrite such as sodium nitrite, you can make a lot of excellent initiators.

[peppovsky]

I will use a PVC tube then. Today I made some 30-40 gr of Picric Acid, hopefully of high quality (will know in a couple of days when I purify it...). After some search and reading I thought of making DDNP as primer - since I (hope to) have TNP, and getting the other ingredients is too easy (H2SO4, NaOH, KNO3, Sulfur). Do you think DDNP will make for a good enough initiator of TNP?

[Charles Owlen Picket]

In a gross (personal) description of the explosive properties of their heavy metal salts (styphnic and picric), they put out more "flame than pop". Testing (COPAE) with PETN showed that in addition to at least one gram of LS the issues included were LACK of compression of the LS in the cap. Additionally there may be a difference between normal and basic nitrated phenol metal salts in their capacity to initiate (again PATR2700).

Note that the testing was done with PETN which is a heck of a lot easier to initiate than nitrated phenols. However this does not mean that LS is without merit.

If one were to initiate picric acid with these salts the comments were directed at the efficiency of the primary as prepared within a "standard commercial constructed cap" (as sighted in the above). It COULD work but the purpose of lead styphnate is to flame or ELECTRICALLY sensitize a classic primary like silver or lead azide.

Lead styphnate is quite valuable IMO for the production of bridgeless ignitors since it has inherent ELECTRICAL RESISTANCE. Coupled with graphite and a carrier agent like barium nitrate (or similar), you could make some very effective bridgeless ignitors with it.

[nbk2000]

LS also has the advantage of being available in the OTC form of firearm primers, if you live in a country where you can get such things.

Washed out with solvent and allowed to dry, it's ready for pressing.

[peppovsky]

I prefer synthesizing my own explosives - I'm just that nerdy science boy, and that's where my interest in those stuff come from ;)

[rangegal]

I remember reading somewhere that firearm primers have sand or ground glass in them for friction? And if so wouldn't that make pressing the LS dangerous? Or would the sand just stay in the primer when the LS is dissolved?

I'm getting some muzzle loader primers soon, I wonder if those would contain LS like rifle primers?

[chemdude1999]

I'm getting some muzzle loader primers soon, I wonder if those would contain LS like rifle primers?

Lately, it is fashionable for manufacturers to use shotgun primers as muzzle-loader primers. They simply repackage them and up the price.

Also, primers DO have ground glass as a frictionator. And, yes, this would make pressing more dangerous, especially with the added sensitizers (i.e., tetracene). Solvent may remove the sensitizers.

Use care when grinding/pressing and only do small amounts.

As a side note, mass production of primers uses styphnic acid and lead oxide (plus other goodies) and creates the primers in situ. Not sure if this has been mentioned.