Making model rocket motor igniters

[Stephan Jones] has an easy method for making your own model rocket engine igniter. The solid state motors used in this hobby consume one igniter with each electrically triggered launch. Whether you’re making your own motors or not, this construction technique should prohibit you from every buying an igniter again. The process involves bending some nichrome wire around a paper clip, adding some structural support to the leads using masking tape, and insulating the business end with a quick dip in paint.

Now would be a good time to send us your launchpad hacks. All we’ve seen so far is a launchpad for water rockets.

[via Make]

Comments

  1. Patrick says:

    Sooo happy its not from instructibles…

  2. Chuckt says:

    We use to use the old flash bulbs from flash cubes. They would also flash when they went off.

  3. Derek says:

    I saw something somewhere that showed old christmas bulbs used for ignition sources, It involved heating them lightly then breaking off the tip and filling with gun/ black powder and using the leads just like you would with nichrome.

  4. Jenna Fox says:

    I’ve heard of people using small diodes as igniters, on the basis that they get crazy hot when driven over-spec with some short circuit.

  5. Matt says:

    I’ve used steel wool before as an ignition source for other various sorts of fun. It heats up rapidly due to the thin nature of the individual wires and you can even pull and roll a thread out from a larger source.

  6. Chris says:

    It seems like a lot of HAD topics coincidentally show up right after some related event or discussion elsewhere. Just yesterday a man in Chesco, PA was killed while mixing homemade rocket fuel. A bit odd, yes?

  7. autom says:

    As a kid, I would take a used igniter, where the thin wire would usually still be attached to at least one side, or I’d supply my own thin wire from a stranded wire from an old toy. I’d fix a match head to that wire, and scotch tape the loose end of the wire back to where it belongs. It was very unreliable, and took a longer button press, but it did get me a few extra shots. I’m sure this, or just about anything, would be more efficient!

  8. Wifigod says:

    @Derek

    You mean like these? :-) http://www.nakka-rocketry.net/igniter.html

    I’ve made tons of these before, once you have the powder made it’s pretty darn simple. Started using them back in high school around 10 years ago.

  9. lwatcdr says:

    The solid state motors????
    Solid fuel yes. Solid propellant yes. Solid state, while it is true they are in a solid state until ignited that is just the wrong term to use!

  10. Unknown says:

    I use to do it, not for rocketry but just to burn stuff safely, with one match a tiny piece of graphite and the weiring. Pretty primitive but effective. A replacement for the graphite could be a couple filaments from a metal sponge.

  11. Don says:

    I remember Estes Rockets from when I was a Kid growing up back in the 60′s and early 70′s!:) Big Bertha was the Biggest back then. I couldn’t afford Bertha. But I had a couple of nice fast Rockets and one with a parachute for a nice soft landing (on a Roof or in a Tree in my Neighborhood;). My first kit didn’t have a Parachute and it would always break something when it hit the ground on the trip back down. I built my first launching pad from a pice of Pine, an old round leg from a Coffee table or something like that and a Coat Hanger. It worked great until I finally got my Real Launching Pad from Estes!:) It looked allot like the 3 legged ones ones on the site Today. I looked and Estes is still around and on the Internet now http://www.estesrockets.com/. It had big enough clips to hook up to a car battery and that’s how I used it most of the time, since those 6 volt batteries would run down pretty quickly. I didn’t get too serious about my Rocket Hobby, but it was great fun, once in a while:) I got them out again when my kids were growing up and we had allot of fun shooting the of together. I still have the Stuff, somewhere in my Boxes in the Garage. I wonder… well maybe later;)

    Don

  12. Anonymous says:

    @Chris

    Probably he was using chlorate based sugar rocket fuel, which is plain stupid IMHO.
    I had a few mishaps with KNO3/sugar propellant and whenever the the fuel ignited when unconfined, it only burned with lots of smoke.
    Chlorate mixes tend to explode in the same situation, however.
    You only have to be careful with nitrate candy fuel if it’s enlosed in a rocket engine, as overpressure can rupture the engine.

  13. damntech says:

    Another thumbs up for steel wool. That’s what I did as a kid.

  14. mrnutty says:

    @Unknown I used to do this with a forward biased 1N914 diode and a match. A 9V battery will get that thing hot in a hurry. When I was a kid you could get a pack of 50 from Rat Shack for $2, which was more worthwhile than trying to solder nichrome.

  15. Jordan says:

    1/8th watt resistors work really well, too. except they tend to stink a bit when the case burns up.

    personally i would never expend nichrome wire when you can use just about any thin wire at the expense of battery life, but using an SLA rechargeable from a lantern works for weeks without a charge if it’s just zapping little wires.

  16. macw says:

    You can get spools of thin nichrome wire for very little money. What I used to do was get some heavy insulated copper wire, twist two pieces together on the insulated section, strip two inches off the end of each, and then wrap a half-inch piece of nichrome around the exposed ends. Clip the power onto the other end of the igniter and you’re good to go. You can sand off the soot after a launch and use the heavy wires at least ten or fifteen times, so your total cost is less than a cent of nichrome.

  17. Wes says:

    Why would making one of these “prohibit” me from ever buying one again?

  18. Sam says:

    Quick and easy version that I did as a kid was some nichrome wire, I think it was $5 for a huge spool out of the back of popular science or something, wrap a bit around the ends of two larger pieces of copper wire. Then I would use a razor blade and make a slit in the end of a paper match and slide the nichrome wire in the slot. Use masking tape to tape the leads on either side of the match.

    9V battery to the copper leads would heat the nichrome wire and light the match…

  19. Glen says:

    I use steel wool teased out into a few strands and wrapped around a match head.
    wires run up opposite sides of the match shank into it and the whole lot is taped up with masking tape.

    Shove a nice big current through it from something like a 6v Cycle lamp and off it goes.

  20. Luke says:

    With the talk of graphite yesterday, I wonder if a small piece of graphite jammed into the motor, set to go on thermal runaway might work well.

  21. dcroy says:

    I am a little curious to whether or not a moderately high powered laser and a strip of black tape would ignite a rocket engine

  22. Einomies says:

    When I was a kid, I sourced something very similiar from an old burned out hair dryer.

    The way I did it was to take two wires, make a small loop on the end of both, put the wire through the loops and squeeze the loops shut with <5mm of wire between them. Then I put a pinch of black powder on the wire followed by a drop of glue.

    It would ignite from a single AA battery.

  23. Terry says:

    The method described here is almost the same as the one Estes used to give out with each ‘tube’ of engines. The difference is the dip in lacquer, which is a great improvement IMHO. The ones I tried to make forty years ago didn’t work so well.

  24. Me says:

    Obligatory: Back in the old days, we just used Impala tail light bulbs… ;-)

    http://web.archive.org/web/20000817114714/http://www.wagoneers.com/pages/RocketCar/rockit.html

  25. zeropointmodule says:

    tantalum capacitors make quite a nice plume of smoke and glow red hot if reverse biased :-)
    speaking from personal experience and a 3mm burned area on me protoboard.. and at least one ruined PCB.
    the ones from old laptop motherboards work well as they are rated at under 5V and 13.8V makes them really really mad and fiery and stuff.
    Sorta like MOSFETS when you use them on small TC’s and induction heaters but they usually explode rather than commit flambuku.

  26. Very nice, definitely useful, thanks !, book-marked.

  27. Metalchemist says:

    What if you made some BP (Black Powder) following all the safety steps.
    A 75/15/10 mix should work well.
    75% KNO3 (potassium nitrate)
    15% superfine charcoal (air-float)
    10% Sulfur
    with 5% dextrin powder (to make it stick)
    (All of these may be obtained from a pyrotechnics supplier for @ 15.00 +/-)
    You can find instructions online, or from a pyro supplier. Be careful no sparks, NO smoking and No flames while making BP….DUH !!!!
    Mix a bit with a 75/25 mix (of water and isopropyl alcohol (rubbing alcohol) It helps the mix dry faster.) till you get a thin pancake batter consistency. Dip the igniter let dry. If you like you can dip in lacquer AFTER it dries.
    This should give a reliable ignition every time.
    You can even find kits to make your own model rocket motors from BP or from KNO3 and sucrose. There’s lost of formulas out there.

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