38 replies to this topic

[whoof]

Discontinued...EEK

[scjb]

Exat. I was looking through websites for spare shocktube tips, when I saw these "EBW" 's from Ideal Supply. I've not used them, but will probably be ordering some now I've seen them...

Edited by scjb, 27 February 2012 - 06:03 PM.

[exat808]

Exat. I was looking through websites for spare shocktube tips, when I saw these "EBW" 's from Ideal Supply. I've not used them, but will probably be ordering some now I've seen them...

It will be interesting to see what you get. Keep us informed.

I have just PM'd "whoof" regarding variances in ST internal diameters. I am aware that some US products have a greater internal diameter than some European items. There is even variance in European production which has led to poor firing results in proprietary initiating machines such as Surefire and Dyno-Start. One user tells me that the internal diameter on some Spanish made tube was so small that the protective coating was being burnt off the electrode after very few firings.

[dave]

Discontinued...EEK

just found farnell stock them, but they do not appear on the cpc site

dave

[whoof]

Exat and scjb, having looked around i see 3 types of device , would i be correct in assuming that ebw and plasma discharge are more reliable/preferred?

[EasyPyro Ltd]

They should look on ebay (etc) for the next Shrike, that will fire down 1000+ metres of bell wire -should be enough! And if it isn't then maybe it's not safe to fire beyond an a position of clear view. Alternatively they should buy a Cooperman special high voltage firing circuit -yours ready to use for under a hundred pounds

We have professional capacitor discharge blasting machines in stock manufactured by Blaster One in the USA. For example the BB30 (http://www.easypyro....lasting-machine ) is a very capable little unit and would initiate shocktube with EBW igniters from http://www.idealblas...bridgewire.aspx , and possible others.

Andrew @ EasyPyro

[scjb]

Whoof. Horses for courses tbh. The EBW for shocktube is new to me, so can't really comment. The one thing that spark (plasma discharge?), shotgun primer and the EBW (from a CD firing system) have in common is that it's tricky to get multiple shots fired sequentially. That was where the NoMatch starters were useful, you could fire lots of shocktube lines as quick as you liked, and the only issue was the parameters of your firing system.

[whoof]

that it's tricky to get multiple shots fired sequentially.

Is there a big need for this in pyro ?
I am trying to do exactly that for a photographic application without the need for licenced pyro devices.
Can you describe the tips you use please ?
Is this the one which uses the jack plug ?
I have assumed that it is a spike which enters the shocktube and is partially insulated to near the tip.

I have a theory on the reliability problem and its causes which i would like to test.

[scjb]

Is there a big need for this in pyro ?

To be honest, not really. Done properly, it's a lot of time and effort for a pretty one-off gag, even by SFX standards. There aren't many clients who are willing to stump up for it, when they can get some massive pyro looks for the same money.

The largest applications of shocktube I've been involved with were (1) for tracing out geometric elements on a stage set, and (2) for the de rigueur lightning simulation. For the set gag, the lengths were relatively short, but lots of them, firing in succession over the course of maybe ten seconds, whereas for the lightning gag, there were 32x long lengths from the mothergrid to the floor, fired in very rapid sequence to try and emulate the long pulse of a lightning strike, with the top end bundled together and progressively branching out all over the place. The speed and short duration of the pulse, whilst the main attraction of shocktube for SFX are also the main problems... sometimes it's just too damn fast! Literally, blink and you've missed it.

I am trying to do exactly that for a photographic application without the need for licenced pyro devices.
Can you describe the tips you use please ?
Is this the one which uses the jack plug ?
I have assumed that it is a spike which enters the shocktube and is partially insulated to near the tip.

It's been ten years since I did anything sequenced with shocktube, so now a single shot Scorpion HR-1 does fine for me when I want to play (ps, don't buy the Scorpion for SFX work, it's not ideal). However, yes the tips are based on a mono 6.35mm jack and are relatively cheap, though I suspect they don't anchor the tube as well as some units (they are just a push fit). I'll get some photo's for you next week.

I have a theory on the reliability problem and its causes which i would like to test.

The only time I've had shocktube not fire was when trying to initiate directly with electric matches. NoMatch, sparks and shotgun primers are all reliable.

EDIT: Ignore my last. I've stuck to one brand of tube (Exchem\EPC), and wasn't aware of the variation in internal dimension with other manufacturers. Certainly for spark initiation it sounds rather annoying!

Edited by scjb, 03 March 2012 - 06:39 PM.

[exat808]

EDIT: Ignore my last. I've stuck to one brand of tube (Exchem\EPC), and wasn't aware of the variation in internal dimension with other manufacturers. Certainly for spark initiation it sounds rather annoying!
[/quote]



This is a major headache for blasting contractors who tend to shop around between suppliers for the best deals in ST whilst relying on a single type of initiator. We tend to use primer initiation but also have a need for a reliable single line electric system, hence the threads here and "the other place".

[EasyPyro Ltd]

Well, what fun stuff to play with! I was kindly sent some ShockTube and after a little experimentation, I've found a reliable "homebrew" way to electrically initiate it. Basically, you need to create an exploding bridgewire igniter (takes about 5 seconds with some tinfoil / aluminium foil) and cut a slit in the end of the shocktube. Slide the shocktube over your exploding bridgewire igniter and put a 330v pulse from a blasting machine (http://www.easypyro....lasting-machine) through it. The foil bridge literally explodes and transfers it's energy to the shocktube. <br style="color: rgb(20, 20, 20); font-family: Arial, sans-serif; font-size: 15px; line-height: 20px; background-color: rgb(252, 252, 255); "><br style="color: rgb(20, 20, 20); font-family: Arial, sans-serif; font-size: 15px; line-height: 20px; background-color: rgb(252, 252, 255); ">The stuff really goes with a bang, but it's completely safe because the tube doesn't fracture or split. I'm going to do some experiments to see if I can get it to reliably ignite quickmatch.


Either way it's great fun.<br style="color: rgb(20, 20, 20); font-family: Arial, sans-serif; font-size: 15px; line-height: 20px; background-color: rgb(252, 252, 255); "><br style="color: rgb(20, 20, 20); font-family: Arial, sans-serif; font-size: 15px; line-height: 20px; background-color: rgb(252, 252, 255); ">Andrew @ EasyPyrp

[dave]

Well, what fun stuff to play with! I was kindly sent some ShockTube and after a little experimentation, I've found a reliable "homebrew" way to electrically initiate it. Basically, you need to create an exploding bridgewire igniter (takes about 5 seconds with some tinfoil / aluminium foil) and cut a slit in the end of the shocktube. Slide the shocktube over your exploding bridgewire igniter and put a 330v pulse from a blasting machine (http://www.easypyro....lasting-machine) through it. The foil bridge literally explodes and transfers it's energy to the shocktube. <br style="color: rgb(20, 20, 20); font-family: Arial, sans-serif; font-size: 15px; line-height: 20px; background-color: rgb(252, 252, 255); "><br style="color: rgb(20, 20, 20); font-family: Arial, sans-serif; font-size: 15px; line-height: 20px; background-color: rgb(252, 252, 255); ">The stuff really goes with a bang, but it's completely safe because the tube doesn't fracture or split. I'm going to do some experiments to see if I can get it to reliably ignite quickmatch.


Either way it's great fun.<br style="color: rgb(20, 20, 20); font-family: Arial, sans-serif; font-size: 15px; line-height: 20px; background-color: rgb(252, 252, 255); "><br style="color: rgb(20, 20, 20); font-family: Arial, sans-serif; font-size: 15px; line-height: 20px; background-color: rgb(252, 252, 255); ">Andrew @ EasyPyrp

andrew,

have you tried using a blank ematch chip with no pyrogen ?

http://martinezspeci...g-Supplies1.jpg

above seems to imply it may work

dave

[exat808]

Well, what fun stuff to play with! I was kindly sent some ShockTube and after a little experimentation, I've found a reliable "homebrew" way to electrically initiate it. Basically, you need to create an exploding bridgewire igniter (takes about 5 seconds with some tinfoil / aluminium foil) and cut a slit in the end of the shocktube. Slide the shocktube over your exploding bridgewire igniter and put a 330v pulse from a blasting machine (http://www.easypyro....lasting-machine) through it. The foil bridge literally explodes and transfers it's energy to the shocktube. <br style="color: rgb(20, 20, 20); font-family: Arial, sans-serif; font-size: 15px; line-height: 20px; background-color: rgb(252, 252, 255); "><br style="color: rgb(20, 20, 20); font-family: Arial, sans-serif; font-size: 15px; line-height: 20px; background-color: rgb(252, 252, 255); ">The stuff really goes with a bang, but it's completely safe because the tube doesn't fracture or split. I'm going to do some experiments to see if I can get it to reliably ignite quickmatch.

Either way it's great fun.<br style="color: rgb(20, 20, 20); font-family: Arial, sans-serif; font-size: 15px; line-height: 20px; background-color: rgb(252, 252, 255); "><br style="color: rgb(20, 20, 20); font-family: Arial, sans-serif; font-size: 15px; line-height: 20px; background-color: rgb(252, 252, 255); ">Andrew @ EasyPyrp

Cross posted from UKFR

Andrew,( and other readers) please be aware that ST will fracture and split in circumstances where the initiation front is impeded. If you intend to use the discharge to ignite other substances please allow a sufficient stand-off between the ST end and your receptor. Also physically pinching or crimping the ST can also result in fracturing of the tube. Take care with your experimentation.

[exat808]

Just met with Cooperman to discuss ST initiation methods. He trialled something along the lines of what EasyPyro has described above with some promising results. Any updates from from the other experiments?

[BrightStar]

Just a quick note on this. Standard electrolytic 'photo flash' capacitors aren't really up to pulse discharge duty for plasma / ebw applications unless you're careful. Yes, they'll work for a few dozen shots but given a low impedence circuit, the cap will progressively destroy itself as the internal foil is damaged.

Ideally you could use a mylar, oil or ceramic HV pulse cap with a fast trigger circuit but they're expensive and bulky. With electrolytics, slowing down the pulse with a long wire, added series inductance or resistance is helpful for e-matches. It somewhat defeats the point for EBW HE / shock tube work though, so it might be a bit of a balancing act...

Having said that, have you guys looked at the Maxim flash charger chips?

http://www.maxim-ic....dex.mvp/id/5323

Interesting thread...