Sciencemadness Discussion Board - Electrical ignition system

Electrical ignition system

greenlight - 27-3-2017 at 20:15

I came across this design for an electrical initiation system for model rocketry.
I would like to construct one but for setting off charges so I can eliminate dodgy fuse but I am not quite sure of the electronics.
The diagram runs of two 9 volt batterys linked in a battery pack but I am quite sure that this will have a very short range for reliable ignition.
Could the power source and wiring be upgraded to a level that it would reliably work 50 meters away every time?
How many 9 volt batteries would be needed to acheive this?

My plan for the actual igniters is to use s small piece of 32 awg nichrome wire dipped in BP slurry and then coated in NC for a protective waterproof layer.

[Edited on 28-3-2017 by greenlight]

XeonTheMGPony - 27-3-2017 at 21:18

Skip the B.P.

Steel wool strands means much less current needed and faster response but a bit more effort in fabrication.

Get an old disposable camera with the flash circuit (Well 3 of them)

Take the caps off the two and solder them to the first.

Use a push button for the flash trigger, desolder one side of the flash and make it so it hookes up in series to your wire.

Gives good range and power dilivered (200+ volts) hence why you need the steel wire, it behaves ideal with this system

Once I made my element I'd dip it a couple times in nitro lacquer to glue it all together. I did all sorts of fancy things like making Nc plastic and using mach head powder and such, eventually I dropped it all as a simple dip in the lacquer was all it really took.

But if the heart is set on it, dip it in the nitro lacquer then the BP

[Edited on 28-3-2017 by XeonTheMGPony]

greenlight - 28-3-2017 at 02:49

So steel wool strand instead of nichrome wire on the igniter?
Is it possible to make the above diagram with a safety switch but with a series of 9 volt batteries instead of just two?

[Edited on 28-3-2017 by greenlight]

Sulaiman - 28-3-2017 at 02:54

I know litle about igniters,
but in the schematic above, the LED needs a series resistor.

XeonTheMGPony - 28-3-2017 at 05:37

As some one who did model rocketry it is! but in the above schematic it is just a "You got power/ Circuit armed" light

the LED is a continuity indicator ensuring the ignition is all hooked up, model rocket igniters are current based, very thick NiChrom.

Any blasting systems function is to ensure power can not be accidentally supplied to the cap while working on it.

For my pyrotechnic system I used an automotive key lock and a SPST covered switch, key was global power, covered switch was the firing system power, and to fire two NO switches must be pressed.

When one of the NO push buttons was pressed a buzzer sounded to warn you are fully hot and ready to fire.

So to make a simple battery operated system use 1 toggle switch that is covered to prevent accident arming and a normally open push button, for the circuit verification use a 4.5K resistor and a red LED across the NO push button, enough current will flow when armed to illuminate the led but to never fire the cap/igniter

[Edited on 28-3-2017 by XeonTheMGPony]

DubaiAmateurRocketry - 28-3-2017 at 06:37

http://www.nakka-rocketry.net/igniter.html

This guy's website have a comprehensive guide in amateur rocketry.

edit: missing word

[Edited on 28-3-2017 by DubaiAmateurRocketry]

TheMrbunGee - 28-3-2017 at 07:48

for igniters: https://www.youtube.com/watch?v=zjAABCRhm8c

As for the launcher I used wireless car lock system and 12V lead battery, got two working channels from it. wireless is allways better!

XeonTheMGPony - 28-3-2017 at 09:37

I just made this in less then 1 minute and used a dead AA to fire it. steel wool is the best, allot of those are rather poor design and use excess material.

Normaly it is allot more packed with more punch, but this was a fast 1 minute demo of the set up.

Start.jpg - 23kB

[Edited on 28-3-2017 by XeonTheMGPony]

XeonTheMGPony - 28-3-2017 at 09:45

Using a staged ignitor allows you to use less material more efficiently.

Easy ignitable susbance> Lesser > Lesser but hotter.

So Wire with steel wool strand doped in NC > NC/Nitroglycerin blend for ignitors.

For caps, first stage is as above, and atm I am using HMTD then ETN final stage. top is capped with paper cap and crimped, bottom is some tape and fused ETN to make a solid plug.

macckone - 28-3-2017 at 18:40

Nichrome wire has higher resistance than steel.
The wire thickness is critical.
Too thick and it won't heat correctly.
Old style flash systems are great for the voltage pump.

greenlight - 28-3-2017 at 23:09

Thanks for all the replies...
I will use a similar igniter to Xeons in the actual cap.
I will have to do some tests and see how much power I need to heat the igniter from about 50m away.

XeonTheMGPony - 29-3-2017 at 05:25

that's the point you want a bit of resistance but not much, it is the current that makes the heat, Steel has just enough resistance but poor thermal dissipation to heat fast and effective with little energy!

@Green, it is volts that push the amps, higher the volts the longer you can go on a given wire I^2R gives you the resistance losses for a given current

200 feet of wire at 14awg at 12 Volts will do the job easily, at 1 amp you'd have a 9.8V potential across the wire ends, plenty to get steel wool to white heat fast, nichrom is much slower. You can go to as low as 16guage, just might take a tad longer to fire, so 2 series 9V will be plenty for the job!

Steel wool: Fast to fire, low energy cheap and widely available, works with capacitor discharge systems effectively. Con: It is delicate to work with and can be finicky

NiChrom: Strong, durable, easy to handle, Con: Expensive, hard to source, long time delay from power to ignition, will not work with cap discharge systems with out very precise length controls.

I have used both and I still do depending on the target goal, but more and more I am using steel wool as it is much better for multicap timed systems for firing patterns.

I blasted out my old cistern using steel wool elements with a pressed time delay using mach heads, it worked but I plan to use a Silicone CaSO4 thermite comp for the next batch of time delayed caps, So for it to work right I need all elements to fully ignite fast off a single energy burst.

Steel wool does this the most reliably in a parallel pattern then nichrom would due to the delay issue

Sulaiman - 29-3-2017 at 06:44

Why not have your high current battery near to the launch pad,
connected to the fuse by normally-open relay contacts, and power the relay coil remotely ?
(e.g. 5 V relay coil and 9V battery)

This way you need not invest in expensive, bulky, heavy lengths of high voltage or current cable.

Praxichys - 29-3-2017 at 07:08

I like to use old Christmas lights. If you're careful, you can clip off the top with a pair of wire cutters to expose the filament. Wrap electrical tape once or twice around the intact portion of the bulb to cover the jagged edge, making a cap shape the diameter of the bulb and about half an inch long. Make an acetone paste of smokeless powder (or use nitrocellulose lacquer, or basically any match paste that will harden) and carefully fill the remains of the glass lamp and tape tube. When dry, check continuity with an ohmmeter. If it's not an open circuit (which means you broke the filament), there is basically a 100% chance it will work. I use a firing circuit made from disposable camera flash caps and a charging circuit, and fire through 1/4" coax cable.

Alternatively, a suitably sized straw can be pressed over the remains of the lamp and 200mg of lead azide poured in, then taped shut for direct primary initiation.

I do this because now that LED Christmas lights are popular, everyone is throwing out their incandescent ones. You can get 150 ready-made filament assemblies for free for each strand of lights you find, and each lamp assembly has about 6" of leadwire already attached.

[Edited on 29-3-2017 by Praxichys]

XeonTheMGPony - 29-3-2017 at 11:22

Quote: Originally posted by Praxichys

--------------------------

[Edited on 29-3-2017 by Praxichys]

Do you all so go by Codies lab? or another guy all together?

I tried to email him once on a more reliable delay system, because he did a sequential blast and had issues.

Tsjerk - 30-3-2017 at 00:01

I once made a mix of graphite and ping pong balls dissolved in acetone. This way I could make pretty consistent electric fuses after dipping a short piece of sound cable in it. This is an easier way than breaking open light bulbs which easily break. Also you don't have to use tape to hold things together as the NC putty becomes a tuff plastic.

yobbo II - 30-3-2017 at 03:35

Quote: Originally posted by Tsjerk

I once made a mix of graphite and ping pong balls dissolved in acetone. This way I could make pretty consistent electric fuses after dipping a short piece of sound cable in it. This is an easier way than breaking open light bulbs which easily break. Also you don't have to use tape to hold things together as the NC putty becomes a tuff plastic.

Is the mixture of graphite and ping pong balls conductive?

PHILOU Zrealone - 30-3-2017 at 14:58

I also use christmass tree light bulbs...the extremity can be easily cuted off with a dremel and this leaves the main cylindric part of the light bulb with the electric tungsten wire integer.

Then you can put anything you want into it BP, Flash, CuO/nano Al thermite, KClO3 BP, NiHN, NC to make ignition devices or SADS to make detonator.The hole needs to be closed with NC glue.

A low voltage (1V) current is sufficient to allow for ignition/deflagration/detonation.

greenlight - 30-3-2017 at 20:13

@xeon, I will attempt to use the diagram with 14 gauge wire and two 9 volts in a series for power and steel wool as the connector in the initiator.

@sulamain, I am nervous for my first attempts at having the power source connected so close to the charge in case of accident. I was thinking I could place the charge, run the cable back and then connect it to the power supply and fire it.

I don't have any of the old christmas light reels here so I will try the steel wool and see how that goes otherwise I found this on ebay. 200 of the old style bulbs with just the wires out the back to connect:

http://m.ebay.com/itm/302159705581

XeonTheMGPony - 30-3-2017 at 20:45

remember to short the end of the wire where you'd hook up the firing modual.

The added safety never hurts!

[Edited on 31-3-2017 by XeonTheMGPony]

greenlight - 30-3-2017 at 23:18

Twist the wires together you mean until ready to fire?

[Edited on 31-3-2017 by greenlight]

dillee1 - 31-3-2017 at 01:39

Quote: Originally posted by PHILOU Zrealone

I also use christmass tree light bulbs...the extremity can be easily cuted off with a dremel and this leaves the main cylindric part of the light bulb with the electric tungsten wire integer.

^This. Although I use 2.4-3.6V flashlight light bulbs+20mg perchlorate flash as pyro primer. With 20m 24AWG, 9V drive voltage it is 100% ignition rate.

XeonTheMGPony - 31-3-2017 at 04:50

Quote: Originally posted by greenlight

Twist the wires together you mean until ready to fire?

[Edited on 31-3-2017 by greenlight]

yup or any other means really, to snuff out any induced voltage in the wire from power lines/radios so on.

greenlight - 31-3-2017 at 05:38

Okay thats extremely important because my site has large high voltage power lines a couple hundred meters away.

yobbo II - 31-3-2017 at 06:24

Quote:

Some conversation:

remember to short the end of the wire where you'd hook up the firing modual.

Twist the wires together you mean until ready to fire?

yup or any other means really, to snuff out any induced voltage in the wire from power lines/radios so on.

Okay thats extremely important because my site has large high voltage power lines a couple hundred meters away.

It is important to tie the wires together BESIDE the bomb. NOT at the end where the battery/power supply is located as this will have the exact opposite effect.

Yob

XeonTheMGPony - 31-3-2017 at 10:07

that makes no sense yobo, you twist the wires to make a short on the end power will go in.

The cap all so should be shunted right up to the point it is connected to the branch/trunk line. Electricity all ways takes the path of least resistance, steel Vs copper, copper wins so any voltage or current is passed at the ends twisted.

twisted wire ends > cable > Charge to be fired

Definitely need to be care full near such an rf source indeed! Test for current with a multi meter be for wiring the cap to it to ensure no accidents!

Proper way is to hook up the cap, secure the wire then un-spool it as you walk away from the charge again to minimize stray current issues and mitigate risk should a sufficient current be induced in the spool despite precautions taken, further away you are the less damage you incur to your self.

[Edited on 31-3-2017 by XeonTheMGPony]

yobbo II - 31-3-2017 at 19:15

The picture gives my understanding of the thing.
If you are shorting for to stop yourself accidently connecting the battery then you are simply being foolish with the battery/supply. Keep battery/power supply away.

XeonTheMGPony - 31-3-2017 at 20:34

it has nothing to do with the battery, you're understanding is wrong for this!

The whole point of shorting at the battery end is to remove any stray induced currents as you HOOK UP THE CAP!! the electricity will be dissipated at the shunt.

Putting a short at the cap is as useless as you can get, how do you expect to fire it when it is shorted!

In transport the cap is to be shunted, you then cut the shunt off and wire it to the trunk line.

You then un-spool the trunk line and snip off the shunt, and wire it to your firing box, at this point you are Armed and dangerous, all people should be cleared befor you cut the shunt!

ANY wire used for the trunk in a firing system should either be parallel strand that is bonded or twisted pair, I use twisted pair as I happened to have allot of it on hand, but speaker wire or coaxial cable will work as well

https://www.gpo.gov/fdsys/pkg/CFR-2014-title30-vol1/pdf/CFR-...

Quote:

726 30 CFR Ch. I (7–1–14 Edition) § 77.1304 (w) Electric detonators of different brands shall not be used in the same round. (x) Adequate priming shall be em-ployed to guard against misfires, in-creased toxic fumes, and poor perform-ance. (y) Except when being tested with a blasting galvanometer: (1) Electric detonators shall be kept shunted until they are being connected to the blasting line or wired into a blasting round. (2) Wired rounds shall be kept shunt-ed until they are being connected to the blasting line. (3) Blasting lines shall be kept shunt-ed until immediately before blasting. (z) Completely wired rounds shall be tested with a blasting galvanometer before connections are made to the blasting line.

There is tons of info on blasting safety and proper blasting procedures, I'd expect any one that is half serious about this hobby to spend a week or better reading them!

In blasting you F*ck up only once, then they clean you up with a mop!

[Edited on 1-4-2017 by XeonTheMGPony]

greenlight - 31-3-2017 at 22:32

I have purchased most of the parts to make the ignition system. I will start wiring it together in the next few days.
I haven't purchased the lead wires that will run out to the actual igniter yet though as it is going to cost a bit more for that much 14 awg cable.
Can I use a normal electeical shunt to connect up until the wires are to be connected to the control system?

[Edited on 1-4-2017 by greenlight]

XeonTheMGPony - 1-4-2017 at 05:10

I just twist the ends together, why buy any thing? Looking good so far

yobbo II - 1-4-2017 at 08:53

I agree with what you are saying.

You should be far away from explosive at the time when all shorts are removed and firing device about to be connected of course.
I am fully aware that you need to remove the shunt from the dedonator!

All I am saying is what the picture and document are saying.

It's a bit of a 'red herring' I suppose in the circumstance as you should not be doing stuff in the vincity of power transmitters but be aware they are all over the place from cb's to door openers etc.
This sort of situation only applies to miltary where rf conditions are bad and you do not get to choose where and when to work.

Use twisted cables or twin cables (as you have said) and do not allow 'loops' to form (places where the forward and return wires are seperated and above ground) if there is a smell of rf.

Attachment: IMESLP20SafetyGuideforthePreventionofRadioFrequency.pdf (5.3MB)
This file has been downloaded 926 times

greenlight - 15-4-2017 at 22:50

I have the switches installed and it is ready to wire up but I have one question.
In the diagram the safety missile switch has three connections on the bottom for power, acc and ground.
In the picture you can see mine only has two. Where would the acc and ground wires go with two connections?

[Edited on 16-4-2017 by greenlight]

XeonTheMGPony - 16-4-2017 at 06:24

it is just a single position single throw switch you do not use any other connections.

basically all we are doing is making 2 breaks in the circuit, one protected break that can not be accidentally closed, and one easily closed break.

the toggle switch is the safety break (Hard to close accidentally) normally there'd be a 4.5K resister and an LED shorting the fire button. LED will glow indicating both power to the firing circuit and circuit continuity yet not enough current to fire the cap, but still placed after the safety switch to be sure.

you want 1 power led to show the system has power, and the armed warning led indicating continuity and the circuit is live to fire.

for what you are doing the light will hook up to the same pin that goes to the fire push button.

battery + > switch tab 1 > Switch tab 2 (Light + lead) & jumper wire > Push button tab 1 > Push button tab two > Blasting trunk line connector

Ensure the switch is in the OFF position with the safety latch closed! and rig up a pull pin in order to lift the safety latch for added security & safety

[Edited on 16-4-2017 by XeonTheMGPony]

XeonTheMGPony - 16-4-2017 at 06:37

Clarification!!

2 L.E.D.s one to indicate Armed circuit condition and the L.E.D. indicating continuity, I noticed I worded it poorly making it appear only one l.e.d. (This is a character fault of simplifying things in a way that make sense to me not others)

Power l.e.d. (Green)
Armed L.E.D. Red
Circuit good orange l.e.d. or red (Orange is preferred to reduce confusion)

This way if 2 out of three light, you know where the fault is and can abort the fire till you test your trunk lines and cap.

You should extensively test your bridge wire and detonator befor it is loaded with any explosives and after final assembly with a digital multimeter to ensure it's quality long befor it gets out to the site of use.

this is where care full attention to assembly pays off to make them all as consistent as possible, for example all my caps tend to be within 1 to 1.5 Ohms and all most never fall from that range, any that do I classify as defective and destroy.

greenlight - 16-4-2017 at 07:30

So I should add another led light to show that there is power?

I am still a bit sketchy on the explanation of how it is wired up. Could you draw a simple schematic similar to the initial one if possible with the added power led in please as that would be a massive help and I will wire it asap.

I will do a lot of testing with igniters and with a voltmeter before I actually use it on a real cap as well.
Thanks Xeon

[Edited on 16-4-2017 by greenlight]

XeonTheMGPony - 16-4-2017 at 09:42

here ya go, the test for power can be omitted given your circuit design, as it is not very applicable nor use full.

tsathoggua1 - 16-4-2017 at 09:50

How about using a marx generator and a thin Al foil strip? Or the tantalum foil from a capacitor. Called an exploding bridgewire, or source a reasonably tough wire from a household low rated fuse, they even have the contacts ready made, would just need the casing of the fuse cracking off, make sure to have a sufficiently rated diode array to prevent the transient current flow before the wire blows returning to the cap bank. The thinner the wire, or strip of foil, the less current it will take in order to blow.

greenlight - 17-4-2017 at 08:36

Okay so without the test button and just having a two connection safety switch, LED and fire button would the original diagram look like this?

[Edited on 17-4-2017 by greenlight]

XeonTheMGPony - 17-4-2017 at 09:38

you need a resister in there or the led would be toast but ya looks correct

greenlight - 17-4-2017 at 09:52

Okay then I will have to purchase one. Would that be connected right before the LED after the connection that leads to the device?
If the resistor is left out wouldn't the LED just run brighter and have a shorter lifetime?

[Edited on 17-4-2017 by greenlight]

XeonTheMGPony - 17-4-2017 at 16:10

No the led will instantly burn out

you need a 2K resistor in series with the LED less it has a built in one, then you'll need just a 1 K in series with it.

greenlight - 17-4-2017 at 18:42

Okay I will go purchase a 2K resistor.
It will go on the positive side of the LED on the right side of it in my diagram like this right?
Thanks for your help just trying to get this right before I wire it.

[Edited on 18-4-2017 by greenlight]

XeonTheMGPony - 18-4-2017 at 04:45

side really doesn't matter so long as the resister is there.

Now if the led you have is rated for 12v it will have 1 resistor all ready, but double the voltage, you need to double the resistance, so if it has a built in one, then 1K resister is all that is needed. 2K will work just be a bit dimmer, but will last near forever!

I'm used to dealing with raw components, seems you have some kind of fancy fangled prepackaged unit there!

[Edited on 18-4-2017 by XeonTheMGPony]

greenlight - 18-4-2017 at 10:25

Yes the LED is rated at 12V. I will purchase a 1K resistor and wire it according to the latest drawing as soon as I can.
Yes everything I have brought is just ready to be connected.
Thanks for your help.

CalAm - 19-4-2017 at 02:49

Here is another eBook i have found on the hazards of RF frequency's when using electronic blasting caps, published by NC Department Of Labor. (NCDOL)

https://archive.org/details/A_Guide_to_Radio_Frequency_Hazar...

yobbo II - 19-4-2017 at 14:25

I believe that I read somewhere or other that if you are blasting close to a great big transmitter, that it is actually safer to NOT have a shunt on the end of the wires of the blasting cap as it is safer to have the wires open. Perhaps a shunt close to the detonator would be OK. (this shunt removed before firing of course).
This only applies to situations beyond you controll like putting a blast under and enemies radar or transmitting aerial.
You cannot very well request that they should shut it off till you get your job completed.

XeonTheMGPony - 19-4-2017 at 15:31

Quote: Originally posted by yobbo II

I believe that I read somewhere or other that if you are blasting close to a great big transmitter, that it is actually safer to NOT have a shunt on the end of the wires of the blasting cap as it is safer to have the wires open. Perhaps a shunt close to the detonator would be OK. (this shunt removed before firing of course).
This only applies to situations beyond you controll like putting a blast under and enemies radar or transmitting aerial.
You cannot very well request that they should shut it off till you get your job completed.

For such demolitions you use safety fuse and a hand firing unit to light it. They are percussion cap based and short of that or a blow torch it does not ignite! (You can split it to enable easier ignition but the whole point of military fuse is it doesn't go off accidentally)

[Edited on 19-4-2017 by XeonTheMGPony]

XeonTheMGPony - 22-4-2017 at 09:30

Figured I'd show you some of the complete cap assemblies I make, the metal one is a 0sec delay, so it goes bang second power hits it, element is 1.75Ohms steel wool

The white ones are paper shelled and where built to accept delays up to 3 seconds! How ever they are set up for 0sec delay.

again steel wool element at apx 1.5 to 2 Ohms, but all ways within that window.

They are primed with some Nitro cotton lacquer, to glue the element on and to protect the metal. you can directly embed it in the primary in loos pack form

Please note how the wires are either twisted or parallel bonded

500mg base charge with 300mg HMTD booster, for the small metal cap it is fulminated mercury 80%/ potassium chlorate 20% at 150mg

So at 6V = 6^2/1.7ohms = 21w of thermal energy dumped into the bridge wire! at 12V = (12^2)/1.7 = 84w! So we can see that keeping the resistance down we get much better energy dumped into heat to the wire. Steel does not hold heat well so it tends to glow white hot easily!

try several metals on a 9v

Tungsten wire is great, but for the hobby level next best thing imo is all ways steel wool, NiChrom is much more valuable for making heaters with!

[Edited on 22-4-2017 by XeonTheMGPony]

Hennig Brand - 23-4-2017 at 05:05

I too have used steel wool as a resistive/heater element with great success, but once I got a 1/4lb spool of 40 gauge Nichrome wire I never went back. The quarter pound of Nichrome wire that fine will last me a lifetime and it cost me less than $60 (had a friend with industrial supply connections). It is much more corrosion resistant, it has extremely consistent and uniform cross sectional area (steel wool is normally very inconsistent), its electrical resistance changes only slightly with temperature until phase change of course. This is not an area I would cheap out, unless it was necessary in an improvisational type situation.

The military firing boxes I have seen for flares etc, had two toggle switches. The arming switch had a cover which had to be lifted to access the arming toggle switch. The firing toggle switch was a momentary switch with a strong spring return mechanism, which would only go to the firing position with a very deliberate push and then return to the no fire position once force was released. Both switches had associated lights mounted above them. I have two or three of these boxes, retrieved from old military vehicles, but I haven't looked at them in a couple of years. The switches were high quality steel toggle switches with rubber seals/boots to keep moisture out all housed in a very sturdy metal enclosure.

greenlight - 23-4-2017 at 22:46

I think I will definitely use steel wool instead of nichrome for the electric caps.

I have wired some of the control box up and have gotten up to the led but I am still stuck on the cables to run out to the actual device.
I went and asked for a price at an electonics shop for 40 metres of 14 gauge wire and its is $108 for that much! It also looks a lot thicker than the stuff in your photo you uploaded of your dets.
I think awg is different somehow from standard gauge.
It says awg is 1.63mm thick in diameter and this stuff was way thicker.
I went to a hardware store and found some wire that looks more like it would suit the whole setup better. It is in the second photo with a vernier caliper measurement included. Would this work as it is much cheaper per metre and would probably cost $30 for 40 metres?
I could find smaller gauge wire with diamter closer to 1.63mm if needed.
[Edited on 24-4-2017 by greenlight]

[Edited on 24-4-2017 by greenlight]

XeonTheMGPony - 24-4-2017 at 07:04

the det leads are 16 guage, they do not need to be large nor the insulation thick, your trunk line needs thick insulation and to be larger gauge.

16awg is the lowest you can go and you need well insulated wire. best bet is reduce the distance, what are you setting off, what are you blasting?

For the most part I use 50 foot of line as most is spot blasting with lots of natural cover, or ground blasting ant hills (Less biting that way!)

greenlight - 24-4-2017 at 07:16

They look very small compared to standard gauge here.
What diameter in mm are the 16 gauge det lines you have including the sheath?

It just seems weird that the wires inside the controller are so small but the wires leading to the device have to be so much larger.
I mostly do dhaped charge penetration of steel targets up to 30 gram of explosive but I like to be safe in case of shrapnel or thrown debris.

XeonTheMGPony - 24-4-2017 at 07:28

need to make a berm, for that stuff I use a pit. easy to dig down then used the soile dug to make a one side berm to further protect me.

Looks mean nothing, lead wire is thin in both conductor and insulation, trunk line is much stronger insulation and conductor as it is subjected to much more handling.

No matter what you pay, you either pay in time and effort or you pay in cash, for me effort is cheaper.

Do some math and calculate safe distance and pit geometry and you should be able to reduce that 150 foot length to some thing smaller!

NeonPulse - 25-4-2017 at 03:06

Quote: Originally posted by greenlight

I think I will definitely use steel wool instead of nichrome for the electric caps.

I have wired some of the control box up and have gotten up to the led but I am still stuck on the cables to run out to the actual device.
I went and asked for a price at an electonics shop for 40 metres of 14 gauge wire and its is $108 for that much! It also looks a lot thicker than the stuff in your photo you uploaded of your dets.
I think awg is different somehow from standard gauge.
It says awg is 1.63mm thick in diameter and this stuff was way thicker.
I went to a hardware store and found some wire that looks more like it would suit the whole setup better. It is in the second photo with a vernier caliper measurement included. Would this work as it is much cheaper per metre and would probably cost $30 for 40 metres?
I could find smaller gauge wire with diamter closer to 1.63mm if needed.
[Edited on 24-4-2017 by greenlight]

[Edited on 24-4-2017 by greenlight]

go to Bunnings. They sell a 100m roll of "bell wire" for about 25$ it actually has a little sticker on the side of the reel that says Detonator wire. It is made for the purpose. It is pretty thin at 1.5mm and works perfectly. It is a solid strand that looks like an alloy or plated copper. Take a look. It's what I use.

initiation system success

greenlight - 25-4-2017 at 03:18

Thanks NP I did end up getting the wire there. I purchased 30 metres of 14 gauge wire and finished wiring the whole thing together today.
Even though the wire is a lot thicker than the internal wiring, it works perfectly.

Thanks for your help Xeon I will dig a dirt berm when I go out next.

I have tested it 6 times and it is only now starting to have a 1 second delay before firing. I took 4 paper sachets of regular black powder out to my usual test site to see if anything went wrong with the high voltage wires about 400 metres away.
There were no accidental misfires and I finally initiated 6 grams of perchlorate flash in a paper tube with no issues.
I will conduct some further test just with small 1 gram sachets of black powder right under the lines next time to double check the safety there because I will never be that close to them.

What do you fire yours with Neonpulse and do you notice a delay when you press the button to when the actual device fires?

[Edited on 25-4-2017 by greenlight]

[Edited on 25-4-2017 by greenlight]

yobbo II - 25-4-2017 at 05:19

If you up the voltage a bit (within reason) the delay will probably be reduced a bit.

greenlight - 25-4-2017 at 05:38

The first 4 there was no delay at all.
I think the batteries get drained pretty fast.

XeonTheMGPony - 25-4-2017 at 07:37

if you use excessive wire for your bridge they do.

a small delay is natural given distance, short of using a capacitor discharge system!

they work by charging a large cap bank up to 200 to 300v larger the cap banks the more caps that can be simultaneously fired