Sciencemadness Discussion Board

Safety fuse igniters (match head composition)?

Fulmen - 18-6-2015 at 02:31

Anyone who has used safety (Bickford) fuse knows how hard they are to ignite. Best trick is to place a match to the end and ignite the match, but it's really a three-hand exercise. So, why not make igniter heads?

I noticed that 22LR cases are a perfect fit, so in theory you could crimp a primed case to the fuse and use a zip-gun style igniter. However I find the primer a bit too energetic for my taste. It also requires a specialized tool that could be mistaken for a gun...

A better solution would be to make a match head that can be crimped onto the fuse. A spent 22-case with a hole in the base should work for that. Ram a small amount of slow black powder into the case and coat the base with a match comp and you should get a nice, reliable system.

Has anybody played with this idea? I'd also like to hear from people who have worked with match head comps. Weingart has a simple composition (chlorate, antimony sulfide and glue), but I'm unsure what glue one should choose.

markx - 18-6-2015 at 03:50

http://www.ebay.com/itm/Windproof-Jet-Flame-1300-C-Butane-Li...


I have found that this type of "jet lighter" gadgets are very convenient for lighting fuses....the flame tip can be pointed with high precision and is very hot. In my opininon much more practical than fiddling around with scratch sensitive compositions.

If a matchhead type mixture is still preferred then perhaps the following could be of use:

https://www.youtube.com/watch?v=lo7XFaBFw2k


Bert - 18-6-2015 at 04:07

Punch the fuse through the powder core and cross match with a strand of black match.

image.jpg - 65kB

I use a leather punch with the smallest size punch for 1/4" time fuse-


image.jpg - 58kB

I also own a purpose made tool for exact spacing of takes fire and gives fire cross matching. Used for multiple effects required to fire simultaneously-

image.jpg - 126kB

Fulmen - 18-6-2015 at 07:00

I'm looking for something that can be prepared in advanced and crimped on when needed. I tried ramming a bit of rocket comp in a pierced case, and it was a bit too vigorous for my taste. So my next attempt will be to ram a 3mm ID spoulette. The end can then be dipped in match-comp and inserted into a straight tube made from a case and crimped onto the fuse. I'll let you know how it turns out.

Hennig Brand - 18-6-2015 at 08:41

I may have gone a little of the intended topic, but you may find something of interest in my post anyway.


Butane Mini-Torch

I use a small butane torch like Markx suggested, though I find the little cigarette lighter types are normally less durable, often produce less flame/heat and are harder to service than the butane soldering torches which are bigger but can still be found in pocket sizes. Here is my butane soldering torch which is about 10 years old now. I remember I got it for $5 on sale. They normally go for around $12-15 here first price I think. I have replaced the piezo igniter in it about 3 times over the 10 year period. The piezo igniter in it is the same type as what is found in many barbeque lighters, etc, with the long flexible extension. I would get one of those from a dollar store for a dollar or so and take the igniter out of it and use it to replace the one in my butane torch. The nozzle has had to be cleaned 6-10 times probably. About 5 years ago I dropped something on the lighter and cracked the casing a bit. I put a few wraps of electrical tape on it and it has held together fine like that ever since (may have replaced the tape once I think). I love my lighter! :D

Anyway, the butane torches produce a very focused localized heat and are very ergonomic. They work great even in fairly high wind.

Butane Torch.jpg - 240kB



Tape Matches to Fuse

Another old trick I have used in high wind when I didn't have my lighter with me was to tape matches (big wooden ones are best, but even paper will do) to the end of the fuse so that 2-4 match heads were positioned directly beside the end of the safety fuse with enough sticking over to strike. When the matches are struck with the striker strip and lit the match heads produce a very intense heat which easily lights safety fuse even in high wind.



High Temperature Electric Igniter

Here is something I found a while back. Sorry, I can't remember what site. It looks like it would burn hot and slow enough and be a very durable igniter. Even a black powder and nitrocellulose lacquer igniter would be fine (I have done it). Epoxy does have advantages though, since it doesn't need to dry to cure. The uncured epoxy pyrogen could be put in a small section of plastic straw the right diameter for the fuse. The electrical igniter could go in one end and the safety fuse end in the other. Both fuse and resistive element pushed into the pyrogen. Once the epoxy cured you would have a very durable, water proof electrical fuse igniter. The igniter could simply be installed on the fuse later as well by leaving enough empty straw casing so it could later be slipped over the fuse and taped in place.


Attachment: Igniter, High Temp, How to Make It.pdf (106kB)
This file has been downloaded 416 times



Electric Lighter

If you would simply like a reusable electrical igniter, why not try one of these electric cigarette lighters, or even just make one. A suitable element could easily be made from a bit of Nichrome wire (the right gauge and length for the voltage and output power and wire temperature) and powered by a battery (preferably rechargeable). As long as the resistive element was designed properly it should last a long time, well maybe not if lighting fuse. I have an idea for a unit where the fine Nichrome is on a spool in the lighter and after the element gets burned out a little more Nichrome is simply unspooled and clipped in place.


Electric Lighter.jpg - 26kB



Electric Arc Lighter

Wow, I don't even smoke anymore and I want one of these! :D


Electric Arc Lighter.jpg - 30kB


[Edited on 18-6-2015 by Hennig Brand]

Fulmen - 18-6-2015 at 11:10

It's pretty much the taped match idea, only more refined. Here's the idea:
Match.jpg - 13kB

Basically it's a short piece of spoulette tipped with a match head and a brass case for crimping it in place.

[Edited on 18-6-15 by Fulmen]

Hennig Brand - 18-6-2015 at 11:24

Looks professional and like it should work. I couldn't be 100% sure until I saw it in action though.

Fulmen - 22-6-2015 at 02:20

Reusing match heads doesn't seem like a working option. I always planned on making match comp from scratch, but figured I could give it a try during development. I simply stripped a box of matches and made a paste with PVA-glue, but it seems to be over-fueled. So next up is Weingarts match-comp (67 KClO3, 22 Sb2S3, 11 glue). Any pointers on this one? PVA seems like a good choice of glue, although NC-lacquer should make it more water-proof. But in that case the comp should probably be reworked as NC has little fuel value.
Storing such comps is another issue. Once dry they are quite flammable and sensitive to friction, I don't like the idea of getting dry comp in the lid of a container. Perhaps a plastic container kept in an air-tight container with some water to prevent drying?

As for the rest of the device it seems very promising. I simply cut the base off a 22LR case and inserted a short piece of 5,5x3,2mm paper tube into the end. The tube was then rammed with a rocket comp I had lying around before primed with match comp. A 22Mag-case would give more room to work with, but on the other hand the LR-case fits perfectly onto the fuse making crimping optional.

NedsHead - 22-6-2015 at 03:58

I worked with my old man who was a shotfirer for a few years in an underground opal mine and we always used sparklers to light our shots, a dozen or more of them at once and only leaving enough time for the winch ride back to the surface.

It was a simple and dependable method used by all opal miners.
Although in that situation the ANFO shots were a good 1500mm down a 3.5'' hole drilled into the sandstone with an auger so sparks being thrown from the sparkler weren't a hazard

Fulmen - 22-6-2015 at 07:45

As you point out sparklers have their own set of challenges. In your example I wouldn't have any objections, but as a general rule I try to avoid anything that sparks. Besides, for a single fuse they would be more work than lighting the fuse directly.

As for my design I'm wondering if I've made it unnecessarily complicated. I'll try a small batch of cases with straight match comp at one end, as long as I crimp the end a bit it should stay in place.

NedsHead - 23-6-2015 at 02:11

Yeah Fulmen, they would be rather impractical for a single fuse and a danger with a short fuse.
Hennig Brand, that hot wire lighter is very cool and I think the best idea so far. I might try and make one with a vaporizer battery I have and some nichrome wire

Hennig Brand - 23-6-2015 at 05:27

Thanks, I thought about making one different times in the past but never got around to it. It wouldn't be hard though I don't think. The element could be positioned well away from the hand holding it too, at the end of a fixed extention for instance, unlike the electric resistive element cigarette lighter above.

Fulmen - 23-6-2015 at 10:11

Bah, my Sb2S3 is nowhere to be found, so I had to use sulfur.
Using The Preparatory Manual of Black Powder and Pyrotechnics as a reference I came up with the following composition:
KClO3 - 50%
PVA-glue - 15%
Ground glass, 120# - 15:
Sulfur - 5%
MnO2 - 10%
ZnO - 5%

The design was also changed to this:

Match2.jpg - 6kB

The case is crimped at one end to ensure positive retention of the match head and flared at the other for easy insertion of the fuse.

Fulmen - 24-6-2015 at 04:30

First tries were moderately successful.
Here are 5 test igniters together with fuse stubs:
Igniters.jpg - 49kB

I did get ignition, but not on the first try. Some might be due to the worn striker, and they might need a few more days to dry out. But I have a feeling I didn't hit bullseye with the composition.
Attachment: Igniter.mp4 (4MB)
This file has been downloaded 792 times

Hennig Brand - 24-6-2015 at 08:23

It does definitely work. Yeah, the composition seems to need a bit of tweaking. I don't know much about friction igniters, but I wonder about how firmly bound the composition is. Does it yield easily, crumble and fall apart before enough friction force can be applied to the match head? It just occurred to me that is what seems to happen to the wooden matches beside the fireplace here in damp weather, that and the moisture also likely makes the composition more insensitive of course.

Fulmen - 24-6-2015 at 14:07

Good news everyone. I just tried two that had been dried out at 60°C for a couple of hours, and they both ignited on the first try with fresh strike pads. So it seems it was just me being impatient as usual. I've made another batch to test, this time I'll try with some NC-laquer for water resistance. But all in all I'm quite satisfied, only downside so far is that they wear out the strike pads quite fast, but that's a minor quibble.

As for the compound it is rock hard, you can put your nail to it without damaging it. I should also add I used the water-proof PVA-glue, I doubt if the regular would behave much differently though.

[Edited on 24-6-15 by Fulmen]

Fulmen - 26-6-2015 at 03:52

The NC-lacquer does not affect performance, after a thorough drying I'm getting perfect reliability. So this little project is completed, all that remains is to make up a decent batch for further use.

[Edited on 26-6-15 by Fulmen]

Hennig Brand - 26-6-2015 at 08:03

Good to see it works well. It is nice when a plan comes together.

Fulmen - 26-6-2015 at 10:16

I know, especially when you eyeball a composition and get it right on the first try.