Unbeliavable AP misfire

[Efraim_barkbit]

Today I witnessed something that I never thought I would experience. I had a failure when trying to set off dry AP with a detonator.
you may or may not find this interesting, I for one did.

It starded yedterday, when I went down to a nearby creek to set off a couple of old cartridges filled with AP. The fuse on the last one died, so I picked it up from the bottom, and left it over night.
So, today, I filled a plastic tube from a bottle rocket with AP, fused it and taped it to the cartridge.

Then I got the surprise of my life, only the det exploded. The cartridge laid about a meter from the site, with a big dent going down it´s side.
I assumed it might have been moist from it´s “bath”, so I took off the tape sealing the opening, and extracted the AP. No moisture at all, and it burned nicely leaving no residue.

So I decided to do another, similar test, so I filled another cartridge with and another bottle rocket tube with AP, and set it off between two bricks.
No detonation of the cartridge, even though the bricks it was placed between had cracked. It had only got a big dent along it´s side.
Fucking strange I say…

Worth noticing, is that I have used the same detonators from bottle rocket tubes to detonate 10%APAN numerous times without failures when the APAN has been inside a piece of plastic pipe, and the det taped to the outside.

I scanned the two cartridges, and a bottle rocket tube so that you can see what I mean.

[FinnBell]

Thats very weird, first of all Ive never heard of anyone using a detonator for a primary explosive why didnt you just put another fuse in it? Personally I wouldnt pick up a dud period unless I KNEW for a fact that it was not going to go off, and even then i wouldnt do it with my hands. Second, when you said 10% APAN mixture, is that 10% AP or 10% Ammonium Nitrate because even a 50/50 mixture is fuse sensitive. Meaning you wouldnt need a detonator for that either.

[Efraim_barkbit]

Of course it is 10% AP,(you almost made me laugh there :D )and I´m pretty sure that a minute underwater will kill most fuses
But you can never know "for a fact"... that, combined with stupidity is probably the largest reason to AP´s many kills.

I used a det because then I wouldn´t have to fuck around with the cartridge, and because I wasn´t sure that the seal has kept the water out of it.
Moist AP is most likely not going to detonate from a fuse.

[Jacks Complete]

Interesting.

I would guess that the brass absorbed enough of the impact, slowing it down so much that the powder could move out the way, rather than being shocked enough to explode.

How full were the cases?

[Efraim_barkbit]

the cases was filled to the top, lightly "tapped" to compact it, this was done repeatedly until it wouldn´t compact anymore from light "tapping" on the cartridge.
then a piece of cloth was inserted in to get a tight seal in the "neck", before it was taped up.
I will make this test once again, but with pressed AP, and report the result.

[utax]

I guess you should try to detonate it with fuse or in different container.

[Jacks Complete]

It's possible that the powder had time to move out the way, pushing the fabric up the neck, and so it didn't get crushed enough to go off.

Let us know how you get on.

[Efraim_barkbit]

I tried it out once more, but this time with packed AP, in both the cartridge and the detonator, and this time, it detonated violently as expected, so I believe you are right jack.

But still, one of the most sensitive primaries known, fails to sympathetically detonate from a detonation less then 2mm away, in two attempts out of three...

[xxxplosive]

does Flash powder have enough "kick" to det AP

if so in what quantity and how, I have been playing with flash as a det with little success.

thanx
EDIT: "thanks" like this? Sory to ofend you but I was not aware that I was doing somthing that required correction ;)

('Thanks' it has a 'ks' at the end and not 'x'. Use a dictionary if you're having trouble. This isn't some shitty chatroom. Also, you've had little success since flash is an LE. But we will be steering well clear of the 'does flash detonate?' topic won't we ;) - kingspaz)

[K9]

I think he was asking if flash can detonate AP, but I don't understand the question then. If that is the question, well then you have a lot to learn. AP is quite sensitive - including flame, friction etc. If for some reason AP doesn't go, then it is quite strange.

[xxxplosive]

my question, More to the point, is I would like to know if AP can be detonated sympotheticaly by flash,

As in Flash in one container, AP in another compleatly sealed container, Flash goes off, then AP goes off by sympatheic detonation.

I hope this new post will clairify my question.

---Thanks---

[K9]

Well that really all depends on the exact circumstances - type of containers, type of flash etc. But for example if it would be a KClO4/Al flash in a film canister and another film canister of AP taped next to it - that would almost definitely go off (not counting for strange circumstances).

[ProdigyChild]

I also had an AP misfire under different circumstances:
A 3mm straw filled with AP and a petrol flame on one end managed to explode half of the straw and leave the other half intact!!

This is well against intuition... (mine at least).

I've got a photo of this, however, I have too few posts so far to attach.

[Boomer]

I hope with "sympathetic detonation" you don't imply that flash actually d****** ? Discussing this is a no-no here. Flash is a low explosive, though a fast and powerful one. :rolleyes:

There have been tests (by others and myself) to avoid primaries by using flash or armstrongs in a cap together with a sensitive secondary like ETN or MHN. These do work but they must be made quite big, and are not too reliable.

The point rather is that AP is so sensitive it detonates from a flame/spark/fuse as soon as it is only slightly confined (straw/paper/alu foil). You don't have to tape an M80 to it, just stick the fuse directly into the AP. But make sure the sparks cannot hit the charge as soon as the fuse starts burning - people have had a bad surprise this way :p

[Efraim_barkbit]

prodigychild, your AP wasn´t completely dry, was it?

[K9]

I've had wet AP fireball. There was chlorate/sugar on top and that went off - and then there was a fireball from the AP underneath.

[ProdigyChild]

I believe it was dry because one should notice difficulties when filling a 3mm straw otherwise!? Not 100% sure though.

I had another near-failure in the meantime, with 6mm straw. It exploded, but no full strength detonation. Filling a straw only partially and using slow burnig powder for the final 3-4cm seems to be not a reliable detonator (with delay).

Design flaw?

[kingspaz]

I think some experimentation is in order to find AP's critical diamter, below which it cannot support its own detonation. After having a look at federoff there is no specific data given in relation to this but there ae results to show it detonates in a 6.3mm column. That could be used as a start point and only try straws on a width less than this.

[Microtek]

Back in the days when I was using peroxides, I made an explosive match by drilling a 1 mm axial hole through the match and filling most of it with pressed AP. The last 8-10 mm ( towards the head of the match ) was packed with KMnO4 and then sealed with wax.
These matches were indistinguishable from ordinary ones, and when lit and quickly blown out the KMnO4 would act as a fuse by oxidizing the frayed wood. This couldn't be detected from casual observation, and about 10 seconds later the AP would detonate, shredding the match.
The explosion was strong enough to fracture a 3 mm plate of PMMA when the match was taped against it.

The point with this story is that the critical diameter of pressed AP confined in thin pine wood is less than 1 mm.

[FrKoNaLeaSh]

There deffinitely must be a critical diameter of AP. On a few occaisions I had filled a pen with AP. Diameter was 3mm. I would assume the pen is LDPE plastic. It was stuck in the ground and fused from end upwards. After inspection of the remaining case there was still a white powder scattered a bit yet all over it assuming to be AP. This white powder burned exactly the same as AP yet was not set off in the blast. So there must have been something wrong.

[ProdigyChild]

Thank God, I'm not the only one to fail with 3mm diameter (on rare occasions!). 3mm or 1mm, both seem to be close to the critical diameter. Success heavily depends on the circumstances like rupture pressure for the casing, ambient temperature, open end diameter.
Also I had never a failure, when using 3mm straws as detcord, i.e. if I detonated it by a reliable device. Even taping one straw to another works well (doubling length). No stop in between.
I believe, the critical part is DDT and if the casing breaks before it.

[Cyclonite]

Iv had balls of AP putty that were a little smaller than the size of a .177 BB. When touched with a cigarette....Detonation. It would blow off the cherry and mushroom out the end. I prefer using putty for a cap due to the fact a casing isn't required therefore there is no need to worry about a casing being to thick or strong for that amount of HE. Also you get a nice density without the hazards of pressing the cap.

[trinitride3]

Hello, can anyone tell me if its safe to use black powder as a primer in a AP cap. Im concerned that the two substances may react with each other. I did an exstensive search of the forum but couldnt find any info on this topic.