Pyrotrons
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Exploding Bridge Wire Detonators, EBW, EBW's, Bridge-Wire, Slapper
I searched for EBW threads, couldn't find any. I must be doing something wrong, my apologies beforehand if that's the case. Extra words in the
subject for search-ability.
The following are my exact notes from Yr. 2008, word-for-word. This was posted (with pictures) to the other forum that existed then. I still have the
pictures, let me know.
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DETONATOR TEST #1
1.54g ETN Initiated with EBW Element
3SEP2008
Hi All,
First, let me post the results, as they are somewhat inconclusive. All I can say is that the remaining brass of the detonator casing was absolutely
pulverized into tiny bits. The largest piece of brass that was found was less than 0.010" in any dimension. The casing was shattered into glitter that
was sprayed around the inside of the hole in the ground where it was fired.
EDIT: The 0.090" thick steel plate was dented by 0.21".
...The plate was deeply gouged from flying brass, but was otherwise unharmed. A curious hole was found in it, about 0.010" in diameter, with the
inside coated in brass (weird pressure jet?).
Judging by the damage to the plate, the detonator must have fallen off-center before firing.
CONSTRUCTION:
DETONATOR BODY:
.30 Carbine rifle shell with primer already fired.
EXPLOSIVE USED:
ETN, created via the NH4NO3/H2SO4 method and recrystallized with hardware-store denatured alcohol. No effort was made to stabilize the ETN, other than
several washes with a weak baking soda solution.
EXPLOSIVE TRAIN:
EBW ---> 180mg @ 0.75cm^3 ---> 180mg @ 1.125g/cm^3 ---> 180mg @ 1.5g/cm^3 ---> 1.0g @ 1.75g/cm^3. It is realized that this may have been
"pointless" but it was hard to get a feel for how much pressure to press with! Measurements were taken after each pressing to find out where to "land"
at 0.75g/cm^3 for the initial pressing (high-density was extremely easy to achieve!).
TOTAL MASS OF EXPLOSIVE:
1.54g ETN.
EXPLODING BRIDGE-WIRE CONSTRUCTION:
0.003" diameter copper wire, 0.05" in length, soldered between the copper pads of a 1/4" square piece of copper-clad circuit board. A dremel tool was
used to make a small "slice" in the middle of the 1/4" land of copper. The tiny wire was then carefully soldered across this gap, making sure to not
thicken the bridge-wire with solder. 20 gauge lead wires were then soldered to the copper lands for connection to the outside World.
ASSEMBLY DETAILS:
The 1/4" piece of circuit board, with the tiny bridge-wire on the surface, was hand-pressed onto loose powdered ETN to "cake" the ETN onto and around
the bridge-wire. This was then hand-pressed onto the surface of the initial 180mg pressing of ETN, and epoxied into place using "J.B. Qwik" (great
stuff!). An endcap was also J.B. Qwik'ed on to seal the device.
CAPACITOR CHARGING CIRCUIT:
A 6kV neon sign transformer was plugged into a variac (variable transformer) to provide 0 - 6kVAC of output voltage. This was then rectified and
filtered to produce 0 - 8.5kVDC. The filter capacitor was also used as the main energy discharge capacitor.
Capacitance: 2uF. Firing voltage: 4kVDC. Input energy: 16 Joules.
TRANSMISSION LINE:
30 feet of RG-8 (50 ohm) coaxial cable to minimize inductance and maximize current rise-time.
SWITCHING CIRCUIT:
Simple bridging of two wires with a screwdriver. This is, in effect, the same thing as the "over-voltage" of or "self-firing" of a spark gap.
RESULTS:
A 0.21" dent in 0.090" mild steel. And a hell of a bang, and tiny brass particles. The 1/8" thick steel plate that the detonator was sitting directly
on was not heavily dented. It WAS heavily "gouged" by flying brass.
Significant energy remained in the capacitor after firing, as evidenced by a goodly-sized spark when shorted. Remaining voltage wasn't measured, but
was probably more than a kV.
[Edited on 19-10-2013 by Pyrotrons]
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Ral123
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If that "detonator" is left on a warm place(let's say the back of a car in a hot summer day) the ETN melts and the thing becomes a dud with no
indication whatsoever.
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underground
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Have you got any link or PDF on how to make ETN with NH4NO3/H2SO4 method ?
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watson.fawkes
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How, exactly, did you search? Please cite the search
facilities and keywords you used.
The most obvious thing, searching for "EBW" on this site's search engine (all forums, entire post), brought up two threads (along with some chaff) on
the first page alone, and this took all of 20 seconds to type in and scan the results.
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Pyrotrons
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I searched for the obvious... EBW, Exploding Bridge Wires, Exploding Bridge-Wires. I saw the two threads you mentioned. They, like all other threads
that I found about EBW's, were lacking when it came to quality and completeness. So I humbly volunteered some of my own hard work to this forum, with
a concise and complete post that starts with materials and ends with test results. My post is original, searchable, and properly titled.
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jock88
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The search engine on this board is the greatest fuck-of-a-thing (no apologies for the language) that was ever been invented on the interwebs.
Go to google. Enter your search term and after the search term type :
site:www.sciencemadness.org
then google will only search sm.o
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Fantasma4500
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a EBW was made with CuO / Al / NC binder i recall, not being very sure if these threads are whats mentioned above? i found that thread very
interesting although..
anyways, if left they should be covered up and only be dealt with by a person who keeps focus and isnt on 9 different drugs when handling them as
Ral123 stated simple sunheat could be catastrophical..
unsure if painting the final device white would remove the risk properly, a package for carrying etc could just be the more simple solution or a
secondary charge to carry it in? (sarcasm)
i think the detonators where a part of the explosive train is removed is widely underrated.. very underrated infact, i believe if a relatively strong
composition with extreme energy output could be used as primary burst charge to initiate the ETN you could also skip the electricity part which would
probably be appreciated by alot as its kinda bulky to drag around wires and all
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watson.fawkes
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Quote: Originally posted by Pyrotrons  | | I searched for the obvious... EBW, Exploding Bridge Wires, Exploding Bridge-Wires. I saw the two threads you mentioned. |
I see.
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