# Igniting model rocket engines
**URL:** https://boards.straightdope.com/t/igniting-model-rocket-engines/708306
**Category:** Factual Questions
**Created:** [December 27, 2014, 10:43pm UTC](https://boards.straightdope.com/t/igniting-model-rocket-engines/708306 "2014-12-27T22:43:13Z")
**Posts on this page:** 20
**Page:** 1
### Author:  [@joemama24\_98](https://boards.straightdope.com/u/joemama24_98)
#### Post date: [December 27, 2014, 10:43pm UTC](https://boards.straightdope.com/t/igniting-model-rocket-engines/708306/1 "2014-12-27T22:43:13Z")
Santa got my son a model rocket kit this Christmas (he may understand that I like to live vicariously).
We took it to a field today and had no luck getting the engine(s) lit - the igniters were not working. I took special care not to bend or break the pyrotechnic and bridge wire at the top, but still not luck, even when I tested one right out of the bag without bending it at all and just hooking up to the launch controller without it being in the engine. We tried all six with no luck, even though the battery tested strong and the circuit completes.
I recall in middle school rocketry club these things rarely worked, and our teacher eventually switched us to fuse wire (as in light a fuse, and run away), and it worked every time. I been out of the hobby for years and can’t find the stuff on Internet or in hobby stores, so perhaps this may have been a “hack?” Anyone have any suggestions on how to reliably light these engines, or reliable products?
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### Author:  [@Johnny\_L.A](https://boards.straightdope.com/u/Johnny_L.A)
#### Post date: [December 27, 2014, 10:48pm UTC](https://boards.straightdope.com/t/igniting-model-rocket-engines/708306/2 "2014-12-27T22:48:31Z")
I presume you know this already, but did you check that the safety key was in place? (If the circuit tested complete, it would have to be. Just asking.)
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### Author:  [@Tripler](https://boards.straightdope.com/u/Tripler)
#### Post date: [December 27, 2014, 10:50pm UTC](https://boards.straightdope.com/t/igniting-model-rocket-engines/708306/3 "2014-12-27T22:50:43Z")
Are you holding down the firing button when going for a launch? My old kit had a pushbutton, and you needed to hold down the button to give enough current to heat the bridgewire and light the ‘match-tip’.
If you’re just pressing it once quickly, you’re not giving the system enough time with just a quick jolt of juice. Press and hold it down to keep the circuit closed.
Tripler
I had an Estes set.
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### Author:  [@Johnny\_L.A](https://boards.straightdope.com/u/Johnny_L.A)
#### Post date: [December 27, 2014, 10:52pm UTC](https://boards.straightdope.com/t/igniting-model-rocket-engines/708306/4 "2014-12-27T22:52:28Z")
That too.
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### Author:  [@beowulff](https://boards.straightdope.com/u/beowulff)
#### Post date: [December 27, 2014, 10:54pm UTC](https://boards.straightdope.com/t/igniting-model-rocket-engines/708306/5 "2014-12-27T22:54:35Z")
How did you test the batteries?
A zillion years ago, when I made model rockets, we used to use a car battery as a power source. A fresh battery, good cables and “solar” ignitors worked almost every time.
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### Author:  [@TriPolar](https://boards.straightdope.com/u/TriPolar)
#### Post date: [December 27, 2014, 10:58pm UTC](https://boards.straightdope.com/t/igniting-model-rocket-engines/708306/6 "2014-12-27T22:58:21Z")
It’s been a while but I remember the igniter failures. Magnesium wire should ignite it, but the fine stuff from flashbulbs won’t do, you’ll need a lot more current, and the wire actually ignites. Nichrome wire should work but also needs more current. There are other techniques but I’m not going to mention the dangerous ways to do it.
Were these Estes igniters? Even those weren’t highly reliable.
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### Author:  [@joemama24\_98](https://boards.straightdope.com/u/joemama24_98)
#### Post date: [December 27, 2014, 11:00pm UTC](https://boards.straightdope.com/t/igniting-model-rocket-engines/708306/7 "2014-12-27T23:00:20Z")
Yes, safety key in and pressed down - it lights an LED that is supposed to go out when you hold the fire button (and it does). I held it down for at least 10 seconds each time and the pyro is not burning. I thought it was a circuit issue but the instructions take you through a sequence to test it and that works, too.
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### Author:  [@Joey\_P](https://boards.straightdope.com/u/Joey_P)
#### Post date: [December 27, 2014, 11:11pm UTC](https://boards.straightdope.com/t/igniting-model-rocket-engines/708306/8 "2014-12-27T23:11:14Z")
> [@joemama24\_98](#):
>
> We tried all six with no luck, even though the battery tested strong and the circuit completes.
>
> I recall in middle school rocketry club these things rarely worked,
I did these in middle school as well (and then on my own around the same time). This would have been in the early 90’s. I remember them going off nearly every single time. Duds were pretty rare. If I were in your situation, I’d take them back to the hobby shop and ask for help. Maybe they can swap out all the parts (engines, igniters, remote, battery etc) and see if they can get you up and running. If this isn’t from a hobby shop you might just want to buy all new parts and see what happens. There’s a weak link somewhere and it’s probably easier and faster to buy all new stuff than to swap out one part at a time a drag the kid out in to the field hoping for the best each time.
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### Author:  [@beowulff](https://boards.straightdope.com/u/beowulff)
#### Post date: [December 27, 2014, 11:11pm UTC](https://boards.straightdope.com/t/igniting-model-rocket-engines/708306/9 "2014-12-27T23:11:20Z")
Get decent batteries - Alkaline or freshly charged NiCd.
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### Author:  [@jz78817](https://boards.straightdope.com/u/jz78817)
#### Post date: [December 27, 2014, 11:42pm UTC](https://boards.straightdope.com/t/igniting-model-rocket-engines/708306/10 "2014-12-27T23:42:01Z")
> [@beowulff](#):
>
> Get decent batteries - Alkaline or freshly charged NiCd.
yeah, this. if you’re using cheap “dry cells” they may not be delivering enough current. I remember from my brief stint with rocketry in the '80s, the Estes igniters always fired. A couple of times they didn’t start the rocket motor, but they fired.
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### Author:  [@joemama24\_98](https://boards.straightdope.com/u/joemama24_98)
#### Post date: [December 27, 2014, 11:50pm UTC](https://boards.straightdope.com/t/igniting-model-rocket-engines/708306/11 "2014-12-27T23:50:48Z")
The batteries are fresh alkalines which even after an hour of use trying are still reading solid on my battery tester. I’m surprised to hear that many of you found this so easy - I remember it being a little frustrating back then, and then now. I honestly expected when we counted down and he pressed the button the first time that it would not work 🙂
So, maybe user error but if so I have no idea what i am doing wrong. Two of the igniters were sacrificial - I hooked them up to the unit without any manipulation but no beans in getting them to light.
Any experience with aftermarket igniters, or even fuse wire? I distinctly remember switching to fuse in the rocketry club, but when I went into a hobby store they had not heard of it (nor can I find it anywhere online). I believe the engines are black powder, so anything that can start a fire should work, right?
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### Author:  [@Just\_Asking\_Questions](https://boards.straightdope.com/u/Just_Asking_Questions)
#### Post date: [December 28, 2014, 12:04am UTC](https://boards.straightdope.com/t/igniting-model-rocket-engines/708306/12 "2014-12-28T00:04:55Z")
Are these Estes?
Unless they’ve had a recent streak of bad quality control, they’ve always been reliable. I’ve pretty much never had a misfire since they went to the “solar” igniters in the 70s. The only time was if they were actually physically broken. There’s got to be something else going on. Put a voltmeter on the clips and see what you are getting.
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### Author:  [@jz78817](https://boards.straightdope.com/u/jz78817)
#### Post date: [December 28, 2014, 12:09am UTC](https://boards.straightdope.com/t/igniting-model-rocket-engines/708306/13 "2014-12-28T00:09:23Z")
> [@joemama24\_98](#):
>
> The batteries are fresh alkalines which even after an hour of use trying are still reading solid on my battery tester. I’m surprised to hear that many of you found this so easy - I remember it being a little frustrating back then, and then now. I honestly expected when we counted down and he pressed the button the first time that it would not work 🙂
>
> So, maybe user error but if so I have no idea what i am doing wrong. Two of the igniters were sacrificial - I hooked them up to the unit without any manipulation but no beans in getting them to light.
>
> Any experience with aftermarket igniters, or even fuse wire? I distinctly remember switching to fuse in the rocketry club, but when I went into a hobby store they had not heard of it (nor can I find it anywhere online). I believe the engines are black powder, so anything that can start a fire should work, right?
ok. put a voltmeter across the output clips of the launch controller and make sure it reads something. could be as simple as a broken wire inside of the controller.
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### Author:  [@zoid](https://boards.straightdope.com/u/zoid)
#### Post date: [December 28, 2014, 12:32am UTC](https://boards.straightdope.com/t/igniting-model-rocket-engines/708306/14 "2014-12-28T00:32:51Z")
> [@joemama24\_98](#):
>
> Any experience with aftermarket igniters, or even fuse wire?
I haven’t seen it for sale in years but M80 fuse (at least that’s’ what we called it) works just fine.
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### Author:  [@GusNSpot](https://boards.straightdope.com/u/GusNSpot)
#### Post date: [December 28, 2014, 1:21am UTC](https://boards.straightdope.com/t/igniting-model-rocket-engines/708306/15 "2014-12-28T01:21:28Z")
Propane torch on a stick? …
…
… What???
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### Author:  [@crowmanyclouds](https://boards.straightdope.com/u/crowmanyclouds)
#### Post date: [December 28, 2014, 1:52am UTC](https://boards.straightdope.com/t/igniting-model-rocket-engines/708306/16 "2014-12-28T01:52:59Z")
> [@zoid](#):
>
> I haven’t seen it for sale in years but M80 fuse (at least that’s’ what we called it) works just fine.
[Visco or cannon fuse](http://en.wikipedia.org/wiki/Visco_fuse).
[Skylighter’s page](http://www.skylighter.com/firework-fuse-visco-chinese.htm) ([there are others](http://www.google.com/search?num=100&newwindow=1&client=firefox-a&hs=4uj&rls=org.mozilla%3Aen-US%3Aofficial&q=visco+fuse&oq=vis+fuse&gs_l=serp.1.0.0i7i30l10.789567.790977.0.792515.3.3.0.0.0.0.348.629.0j2j0j1.3.0.ehm_loc...0...1c.1.60.serp..0.3.622.FpNVAso7sfI)), DO NOT buy [anything other](http://www.skylighter.com/mall/ignition.asp) than plain American or Chinese Visco type fuse unless you really understand what you are buying and doing! (These are fuses for amateur pyrotechnic displays and you really don’t want to buy fast fuse by mistake!)
CMC fnord!
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### Author:  [@Tangent](https://boards.straightdope.com/u/Tangent)
#### Post date: [December 28, 2014, 5:06am UTC](https://boards.straightdope.com/t/igniting-model-rocket-engines/708306/17 "2014-12-28T05:06:57Z")
Maybe too obvious, but be sure the opposite clips of the starter system–or the igniter wires themselves–are not touching each other and shorting the circuit. When I had a ‘no ignition’ event, that was often the problem. Most of the time, when everything was connected correctly, the Estes igniters worked great.
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### Author:  [@Amateur\_Barbarian](https://boards.straightdope.com/u/Amateur_Barbarian)
#### Post date: [December 28, 2014, 5:21am UTC](https://boards.straightdope.com/t/igniting-model-rocket-engines/708306/18 "2014-12-28T05:21:09Z")
So, just to be clear… nothing has made an igniter fire? If that’s the case, the problem is with the controller and nothing else. Absolutely no reason to wonder about the igniters, engines, etc.
Can you do simple electrical testing? Clip the igniter leads to the battery tester and see if it responds when you press the launch button. (Put it on a 6v or higher setting if it has one.)
If you can’t get a voltage reading close to 6v - probably that or nothing - the controller or lead wires are faulty. Use a simple 6v lantern battery and the launch wires, not the rather Mickey mouse switching of the controller.
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### Author:  [@Johnny\_L.A](https://boards.straightdope.com/u/Johnny_L.A)
#### Post date: [December 28, 2014, 3:44pm UTC](https://boards.straightdope.com/t/igniting-model-rocket-engines/708306/19 "2014-12-28T15:44:00Z")
> [@Tangent](#):
>
> Maybe too obvious, but be sure the opposite clips of the starter system–or the igniter wires themselves–are not touching each other and shorting the circuit.
Also make sure the clips aren’t resting on the blast deflector, which is metal. But the OP said an ignitor was tested without being in an engine.
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### Author:  [@joemama24\_98](https://boards.straightdope.com/u/joemama24_98)
#### Post date: [December 29, 2014, 2:20am UTC](https://boards.straightdope.com/t/igniting-model-rocket-engines/708306/20 "2014-12-29T02:20:09Z")
Thanks for the advice, all. Turns out it was the battery, which repeatedly tests solidly good on my tester (and when connected through the launch controller yields the same result on the controller terminals). This was a slightly used Rayovac.
I purchased a brand new Duracell 9v that tests slightly better and it ignited two of the igniters right away that the other did not). I did not realize how sensitive the set-up was - this controller uses a single 9v, whereas I thought only 6v (4 x AA) was typically needed (at least that was what i recalled, anyway).
Do different brand batteries in the same format deliver different amperage? Or is that purely a function of slightly used vs. brand new? One of you suggested a 6v lantern battery…is that simply more reliable for this because of capacity? If so I may keep one as a spare, or perhaps lug along my 12v Celestron Power tank (though I don’t know if there are drawbacks to using more juice that the ignitors are designed to handle). Thanks for the advice!
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