Lighting a floating campfire 50 yards away

[HIMNL9]

most simple of any other thing ..... do you have the possibility to find 50 yards (some more is better) of telephonic cable, also old one, and a 12V battery ?

if so, all that you have to do, is build yourself 2 or 3 ignition devices (never use only one, cause anything can fail), and a switch, and you have solved your problem in the more simple way ..... wire the fire place with the telephone cable, attach the ignitors on fire site and the battery on your site (with the switch, ofcourse), and when you want to turn on the fire, just turn the switch and it's done.

And if you don't find the electric ignitors, i can also say you how to make them yourself, if you want, is easy.

 

[rocketparrotlet]

I love glycerine and permanganate. It gives you about a 10 second delay before it lights, by the way. Here's an idea: use glycerine and permanganate to light a fuse that has the given delay, and then have a pile of flammable material at the end, or just smother the wood lin lighter fluid.

I use glycerine and permanganate to light homemade fireworks. 10 seconds is a lot of time.

-Mark

 

[jayrob]

You could build a cheap sacrificial PHR blu-ray to have mounted, focused and aimed at your flammable target on board. The only tricky part would be to have a remote switch to turn the laser on.

Obviously, you would ruin your laser and that end of the remote switch. But it could be made to work flawlessly in this way from that distance...

There may be some type of remote igniter, instead of a laser...
Jay

 

[Switch]

lol, yea, there's no point in using a laser if you're not firing it from the distance....

 

[k1kb0t]

Use the laser for effect, and then ignite it remotely like HIMNL9 suggests.

Jon

 

[jamilm9]

most simple of any other thing ..... do you have the possibility to find 50 yards (some more is better) of telephonic cable, also old one, and a 12V battery ?

if so, all that you have to do, is build yourself 2 or 3 ignition devices (never use only one, cause anything can fail), and a switch, and you have solved your problem in the more simple way ..... wire the fire place with the telephone cable, attach the ignitors on fire site and the battery on your site (with the switch, ofcourse), and when you want to turn on the fire, just turn the switch and it's done.

And if you don't find the electric ignitors, i can also say you how to make them yourself, if you want, is easy.

how do you make them

 

[Benm]

How are you going to see an IR beam to aim? The fires are out in a lake.

You're not, but that doesnt really matter. If you point a flashlight at something, and turn in on after, you'll generally be pretty much correct. These things arent lasers, with 10-20 degree opening angles anyone can aim blindly.

Being a laser geek i'd obviously mount a visible laser on top as a sight so you know exactly where you are pointing the thing, but thats besides the point ;p

 

[rkcstr]

It's pushing the limits on distance (says 120ft), but you could try one of these:

Predator Remote Fireworks Ignition System - CannonFuse.com

It's a consumer version of a wireless ignition system and is pretty cheap. If you're near a Phantom Fireworks, they sell them there as well.

Otherwise, you could do the wired up version of what others were saying here and make some electric matches to ignite whatever.

 

[Bionic-Badger]

I can just see the headlines this summer. Aside from the regular Boy Scout-caused forest fires and lost kids, we'll see a nice headline proclaiming that some dad-turned-scout-leader decided to attempt to start a fire on a lake using a laser, only to cause injury and lawsuits galore.

Think about it: you're attempting to shine a high powered laser, OUTDOORS, at a combustable target sitting in the middle of a reflective surface, in front of potentially hundreds of children not wearing protective eyewear--at night no less. One errant miss could mean a kids' eye is permanently damaged, resulting in lawsuits galore. It'll literally be the death of private laser ownership if a kid gets hurt or that laser causes a fire. If the news gets ahold of this information you will probably be cited for reckless child endangerment, illegal use of a high powered laser, and other stuff.

It's bad enough we have idiot, untrained scout masters who let the kids wander off, start forest fires, damage prehistoric carvings, shit into rivers, and other idiocy. You don't need to have dangerous lasers added to that list. You might as well try starting that fire using professional cannon fireworks.

For the sake of all laser owners, your Boy Scout troop, and yourself: DON'T DO IT.

 

[HIMNL9]

how do you make them

The easiest ones, you can make with some thin nichel-chrome wire (you can also mangle a 200 / 300 ohm 15W ceramic resistor, if you don't find it in more easy way, but you can find it also in heathers, heat wires, old toasters, and so on) and some pieces of telephone cable (2 wires, single core copper wire)

take also the fuses of some poppers (petards, whatever you call them), the ones that are made with paper and black powder, and cut or bend them approximatively 8 or 10mm lenght, you need 10 or 15 pieces for each ignitor, the number is not important, but, more they are, better they burn .

For more indications, look also the images.

Type 1, coaxial mount ..... just put the fuse pieces and the wires together in the way you see in the draw, keep them together with 10 or 12 turns of ni-cr wire (thin one), or 5 / 6 turns, (if you only found the 0,5mm strip from the toasters, instead thin wire), and fix the extremities of the ni-cr wire to the extremities of the phone cable wires as shown (remember that you can't solder the wires, so for fix it, just turn it around the copper wire some turns, then bend the copper wire and squeeze it, as in the pic).

About the number of turns of ni-cr wire, make some experiments for get the better number of turns for the wire that you found, cause i can't know what type of wire you can found.

type 2, match shape, just keep the phone cables as shown, putting the fuse pieces only around the long wire, and do the same as in the previous one.

Type 3, waterproof ..... take some of the little lamps that you usually use for christmas tree decorations, and break their points, without break the rest ..... fill the class tube half to 3/4 with black powder (you can make it yourself or use the one in the paper fuses, as preferred), then close the hole at the top with hard glue (2-components epoxy resin, the 5 minutes type, is enough, be sure to place a tear of it on the top but not let it go on the powder, nor turn the lamp upside down til the resin is completely dry)

For ignite fuses and powders, they can be used also in this form, but for be sure to ignite paper and other for a camp fire, one more passage is better (for the 2 types with the fuses, i mean ..... type 3 is better for blow other powders)

If you have matches, take away the cap (the ignition parts), of some of them, say, 50 or 100, if you have patience ..... put all the caps (without the wood part ! ) in a mortar or similat, and wet them with water and acetone (yes, water AND acetone together) ..... stir and mix til the caps are all melted in a paste (adding some acetone when it evaporate, if needed), and when it's all of the consistence of a dense paste, cover the igniters made with the fuses and ni-cr wires with that paste, then left dry completely ..... this make a better flame when they ignite, and permit you to use them also for start paper under the wood for a firecamp, or if you use some paraffine or "barbecue igniter" fluid, or similar, on fabric, then you can weap the igniter in some layer of pliofoil (food conservation plastic, domopak, whatever you call it), and then wrap around it the soaked fabric, and it still ignite all, where instead, with just the fuses, it can also not be enough.

By the way, if you're not sure about how to manage chemicals, is enough that you take the powder and pieces of 20 or 30 matches caps (at this point you can also just cut away them, don't care if there's also the wood in the caps), and pack them all around the fuse packet with 5 or 6 turns of that plastic foil, keeping all tight together, then wrap the sides on the wires and roll them with cotton wire or similar, for keep all in place.

Anyway, as suggestion, i still say you to use 2 or 3 in parallel, instead just one ..... remember Murphy's laws

And make also some experiments, about the turns of the wire of ni-cr, cause i can't know what one you can find there, and can be diffrtrnt from mine.



@ Bionic Badger: if you use a circuit with ldr and ignitors, you don't need to use a powerful laser, also a 10mw or similar is enough ..... but you need good sight and firm hand, anyway ..... and if instead you just want to do the scene, and have already one of those remote control igniters, just aim the fireplace with your 50mW greenie and push the button of the remote control unit in your pocket .....

 

[jamilm9]

thanks for the very long post and help +1 to you

 

[k1kb0t]

Nice tutorial HiMNL9 thanks for sharing.

Jon

 

[YGG]

Just so you know I don't think fuel would work, I tried to lite a stick with gasoline on it and it just smoked, a laser doesn't usually provide the spark you need for ignition, just a bunch of radiation. BTW has anyone ever tried popping a balloon with flammable gases inside?

 

[Benm]

I dont think anyone is seriously considering using a laser so powerful its the actual ignition source.

If you go for a remote-control setup you can use IR for the link, but you can also use modulated laser light obviously. This would not have to be particularly powerful, and eye-safe 1 mW would easily make it 120 feet to send a control signal.

 

[jayrob]

As someone mentioned earlier in this thread. The coolest would be to remote ignite the fire, but use a green beam from the shore to give the illusion that the green beam lit the fire...

They would be impressed with just the green beam in the sky (if at night), but when you lock it onto the floating camp fire, and then light it with your remote, that would be awesome!
Jay

 

[psyci]

Thanks for all the great ideas, everyone!

Some responses to various people:

Timers: The campfire lasts about 30 minutes once started. There's a 1 hours window or so when we get the signal to start them, when the scouts are on their way. So can't use timers - we'd more than likely set them off too early or too late.

Pull-String Friction Ignitions: I'm a little worried about their reliability. Pulling a 50 yard string with just the right amount of force is very hard, since you really have no concept of how much slack is in the line. Yes, could add redundancy, but 3 fires x 3 ignitions is a LOT of string to be running around, sounds like a cause of accidents to me, and I really need a sure thing.

Electrical Ignition: Have thought about this. Simplest way to start a fire is battery + wire + steel wool. But running this kind of electricity through a wire that will most likely be underwater worries me. Plus the weight of 50 yards of wire is problematic.

Flaming arrows: Thought about it, but it's just too hard to hit. We don't have expert archers, and we'd need a very good quality bow and arrow, not the cheap stuff the camp provides to do it.

Safety and environmentalism: This project will be done by safety-minded adults only. No kids allowed with this kind of thing. And naturally, anything that sounds like it's getting out of control - explosive material, dangerous chemicals, or super-powerful and expensive lasers - we're just not going to do. I'm looking for a junior-high-school-science level project, not a catastrophe in the making.