Static electricity and primers

[Trailrider #896]

Has anyone ever heard of static electricity causing primers to fire? I know that BP should be shielded from static-generated sparks, but what about primers? I've never heard of static discharge setting off a primer, but how about anyone else out there? No, I've never had a problem, but am wondering about a theory that static electric discharge from helicopter rotors over water possibly setting off what I have understood to be percussion-fired initiators on a certain spacecraft after it landed.

 

I would think if there was a concern that various small arms primer manufacturers would put a warning on the boxes.

[Blastmaster]

possible, but, not probable.

 

Just my hunch.

[BLACKFOOT SASS #11947]

I definitely will not carry my primers in a helicopter over water. Just won't take the chance!

 

Blackfoot

[Garrison Joe, SASS #60708]

Never heard of an occurrence. Never seen a warning on any packaging.

 

I wouldn't generate extra static just for fun. Could (very low risk) not be so much fun.

 

Good luck, GJ

 

 

 

a theory that static electric discharge from helicopter rotors over water possibly setting off what I have understood to be percussion-fired initiators

 

Perhaps the concern was causing an actuation of the solenoids (or other mechanisms) that did the "percussing" of the primers.

 

 

PS -

Now that you got me a little interested, here's a reference to a Frankford Arsenal paper from 1973.

 

1973-10032
18 Sep 73
24P
FRANKFORD ARSENAL PHILADELPHIA PA
SUSCEPTIBILITY OF ELECTRIC PRIMERS TO ELECTROSTATIC DISCHARGE.
Meeting Paper
Schlack, A. F.
This paper was presented at the Fifteenth Explosives Safety Seminar, held at the Hyatt Regency Hotel, San Francisco, CA on 18-20 September, 1973, Vol. I, AD 775-580 (73-10001), P 637-660.
Availability: NTIS/DTIC - Approved for public release; distribution is unlimited.

Priming mixtures made with lead styphnate are highly sensitive to electrostatic discharge. If stray static charges ignite the primer during handling, serious injury and/or damage could result, especially if the primer is assembled in a loaded cartridge. Therefore, several studies were initiated at Frankford Arsenal to decrease the susceptibility of the primer to electrostatic discharge by modifying the priming composition. It was found that the addition of boron to the composition decreased its electrostatic sensitivity. Another study indicated that substituting Trisal for lead styphnate also decreased the mixture's sensitivity.

 

 

 

Short form - this research found lead styphnate (the main part of current (toxic-version) firearms primers) is very static sensitive. But that in 1973 the Arsenal was experimenting with several additives to reduce the sensitivity. Since we don't see large attention-grabbing warnings on primers today, I take that to mean they were successful at removing most of the static sensitivity through use of additives.

 

I would still think it would be wise to reduce all possible static electricity sources when loading ammunition.

 

 

By the way, this came from a CalTech design web site. http://www.design.caltech.edu/micropropulsion/styphnate.html

For you pards who claim what we normally do is NOT rocket science, this is one area where it IS rocket science.

 

 

Good luck, GJ

[Blastmaster]

I guess a bolt of lightening is a electric static discharge and all bets are off when lighting strike hits primer cash. That is worst case scenerio of static and primers, but the concept would be the same for a significant static discharge on/in to primer.

[Garrison Joe, SASS #60708]

Ok, here's Winchester's current Safety Data Sheet.

 

http://www.winchester.com/SiteCollectionDocuments/pdf/SDS/LEAD%20STYPHNATE,%20BASIC.pdf

 

They say this about storage conditions for lead styphnate:

 

Store in a cool, dry, well-ventilated place away from all sources of ignition. Do not store at temperatures above 65.5°C (150°F). Store as prescribed by Bureau of Alcohol, Tobacco and Firearms guidelines for explosive storage. Store away from Acids, Class B & C explosives, strong oxidizers, and caustics. Avoid mechanical impact or shock and electrical discharge.

 

 

 

Bolding added for emphasis.

 

So, I would expect that some degree of explosion hazard exists with a "strong enough" static discharge.

 

Good luck, GJ

[The Original Lumpy Gritz]

Soldiers carry live ammo and EXPLOSIVES in helicopters all the time.

OLG

[Buffalo Douglas]

Winter's up here, the air gets pretty dry and we get plenty of static buildup just walking around the house or sitting on the couch. I don't know if it would actually cause an issue, but to be on the safe side I usually discharge by touching something metal that isn't attached to my press. Sometimes if I can feel some more static building up (like the slightly raised arm-hair sensations) I discharge myself again. If I'm feeling especially squirrely, I drag my feet on the carpet as I sneak up behind Mrs. Douglas

 

That's the limit of any sort of static discharge I've come across. I've never seen anything happen in my 10 years of SG reloading or my year and a half or so of cartridge reloading. Although, I don't think that means it can't happen, just probably unlikely due to the additives that are now added (thanks to the information from GJ). Now a larger current discharge such as a broken wire from a house or building would probably be a completely different matter.

 

The real question for me is this: If we are supposed to keep BP in static free containers, drop tubes, scoops, why does Goex ship in plastic bottles? If you look on forums or get information from any experienced reloaders, they all say use brass funnels etc. Is there something special about the plastic they use that I'm not aware of?

[Springfield Slim SASS #24733]

The plastic bottles have additives that don't allow static build-up. All plastics are not equal.

https://en.wikipedia.org/wiki/Antistatic_agent

[Buffalo Douglas]

The plastic bottles have additives that don't allow static build-up. All plastics are not equal.

https://en.wikipedia.org/wiki/Antistatic_agent

Well that answers my question. Thanks Slim.

 

I figured that was probably the case, but I didn't know for sure.

[The Original Lumpy Gritz]

I live in the desert so dry and wind is everyday here.

I have my presses hard wire grounded to a dedicated ground rod. The real advantage to this, is no static cling in the PM and more consistency in powder charges.

You have more to worry about in the gasoline siting in you car that's siting in your garage.

OLG

[Colorado Coffinmaker]

THE SKY IS FALLING!! THE SKY IS FALLING!!! THE SKY IS FALLING!!! Wait ...... no it's not ..... that's just dandruff.

 

OLG got it in one. The amount of actual hazard is measured with a Microscope!! Meh

 

Coffinmaker

[travelin kid #51083]

A friend of mine was using a Lee hand primer, with Federal Primers, there was a spark, they detonated, he was NOT seating one at the time of detonation, needless to say trip to ER and picking bits of primers out of his hand was the result. There was not other explanation except for static discharge being the cause.

As many people that have done this with no incident, my guess is all of the stars would have to be in perfect alignment for something like this to happen.

[The Original Lumpy Gritz]

A friend of mine was using a Lee hand primer, with Federal Primers, there was a spark, they detonated, he was NOT seating one at the time of detonation, needless to say trip to ER and picking bits of primers out of his hand was the result. There was not other explanation except for static discharge being the cause.

As many people that have done this with no incident, my guess is all of the stars would have to be in perfect alignment for something like this to happen.

That hand primer is made with non-ferrous metal. It can't create a spark. What did he put it on, a battery?

I have been reloading for over 50+ years and have never seen any proof of this, that could not have been 'stupid' induced.

OLG

[Garrison Joe, SASS #60708]

 

 

THE SKY IS FALLING!! THE SKY IS FALLING!!! THE SKY IS FALLING!!!

 

All of the other comments carry little weight compared to what the manufacturers put in their SDS (safety data sheets). Those are the comments and warnings that DOT inspectors, firefighters and hazard containment crews, and industrial workers all bet their lives on.

 

NO one said the sky was falling. Go back to what TR asked about in the original post. Try staying on topic, pards.

 

Good luck, GJ

[Trailrider #896]

My reason for asking was because one theory raised about why astronaut Gus Grissom's Liberty Bell 7's hatch fired "inexplicably". One theory raised is that static electricity caused by the rescue helo's rotor blades near the ocean might have built up to the point that when the hoist was lowered and touched the lift loop, it discharged and set off the initiators. Now, according to some MacDonnell engineers just before the press conference, the opinion was that the mechanism to fire the hatch consisted of a block riding in a channel. The block contained two spring-loaded firing pins, which would impact the initiators, which were basically two primers (shotshell or maybe small rifle primers). A safing pin prevented the block from moving into position until the astronaut (a)pulled the pin, and ( reached over his left shoulder with his right hand, giving a plunger a pretty firm shove. The plunger was springloaded so it would snap back after being released. The plunger cable was not attached to the block because after firing, the firing pins would lock it in place much like a non-rebounding hammer/firing pin would on a shotgun, etc.

 

I have worked around percussion fired ordnance, including the reefing line cutters for the Space Shuttle booster recovery parachutes, and while we did have a FTF on a flight (which is why there were two cutters per reefing line), we never had static charges fire anything, at least while I was on the program. In another example, when Apollo 12 was launched through a heavy cloud cover, a static discharge occurred between the launch vehicle and the surrounding cloud (they first thought they were hit by lightning), which temporarily knocked out their computer and guidance system (the astronauts were able to reset it), yet none of the ordnance on board fired. Similarly, on Minuteman I, we were only allowed to go down into the equipment rooms wearing parkas with cotton shells, not the other standard nylon shell. The nylon shell could build up several thousand volts of static charge. But the concern was not setting off ordnance of any kind (separation rings with linear shaped charges, used to stage the missile), but to keep from zapping the electronics in the room surrounding the missile.

 

Just curious. Thanks for the info.

[Garrison Joe, SASS #60708]

"Discussions of static generate more static than that which the discussion was about."

 

Good luck, GJ

[The Original Lumpy Gritz]

Trailrider, Sounds like all the 'dets' you worked with were designed to be set electronically, and not by impact. That's a whole other world.

OLG

[Matthew Duncan]

https://youtu.be/b89x8CAS6xU

[Matthew Duncan]

Static/stray voltage almost took out an aircraft carrier!

 

https://youtu.be/6g6l_gjxXM4

[Trailrider #896]

Trailrider, Sounds like all the 'dets' you worked with were designed to be set electronically, and not by impact. That's a whole other world.

OLG

On Minuteman, yes. The reefing line cutters on the Shuttle Booster parachutes were mechanical, effectively a trigger mechanism that was pulled by a lanyard attached to the booster. When the separation ring holding the frustum (nose cone) to the forward skirt fired (electrically), the drogue parachute which had been previously deployed pulled the frustum off, deploying the main chutes in a reefed condition so the high velocity wouldn't blow the chutes. As the chutes deployed lanyards connected between the booster and the reefing line cutters (2 each for the two reefing lines for a total of 4), pulled the triggers, which fired MIL-SPEC small rifle primers, which in turn set off a powder train timer. When the timing fuse burned over the elapsed time, the cutter's main charge fired propelling the guillotine cutter through the nylon reefing line. The timing fuze on the second line's cutters fired later to allow the chute to fully deploy. The reason for two cutters per reefing line for each of the three 136 ft. dia. main parachutes was for redundancy. In case one didn't fire the other would still disreef the chute. On one occasion, after the chutes and the boosters were recovered, it was found that ONE cutter hadn't fired in spite of the primer clearly being dented by the firing pin. The other one fired okay. NASA jumped all over Olin (Winchester, don't ya know???) telling them they didn't want another FTF, ever! Olin replied that they expected one FTF every 20,000 primers, and if NASA wouldn't accept that, they could go qualify another vendor! End of that discussion! So, if you get one FTF out of 20 boxes of primers, you are within their specs!

[The Original Lumpy Gritz]

Was the 'bad' primer a std ammo primer we could buy? Most of the dedicated explosive primers I've handled were made just for that purpose, and would not fit in a shell case.

In another life-I hauled class 1.1 'stuff' for Uncle Sugar and learn'd much.

 

OLG