Ignitor lead wire?
- Thread starter sunderll
- Start date
Help Support The Rocketry Forum:
scsager
Slightly burned-out old guy
- Joined
- Apr 24, 2010
- Messages
- 1,779
- Reaction score
- 80
blackbrandt
That Darn College Student
- Joined
- Mar 18, 2012
- Messages
- 9,281
- Reaction score
- 60
Do you go to a club launch? Put a bucket next to the HPR pads with a sign that says "Spent Ignitors". Free, and they work great.
GregGleason
Well-Known Member
- Joined
- Nov 13, 2009
- Messages
- 4,674
- Reaction score
- 45
+1 on Aerocon.
Greg
Greg
stealth6
insert witty tagline here
Another common source is CAT5 wire. It's often possible to find some scrap. But purchasing it is cheap at any local hardware store. It comes usually with 5 pairs (or 4) bundled together with an easily removable outer sheath (often grey or blue) - so if you buy just 5 feet of it, you actually have 50 feet of wire. Quite a few commercially made "starters" (or "igniters" if you will) are made from this wire. It's also great for wiring AV bays and such.
Look for it as "phone wire" or "Ethernet wire". Looks kinda like this:
s6
Look for it as "phone wire" or "Ethernet wire". Looks kinda like this:
s6
Last edited:
TopRamen
SA-5
- Joined
- Aug 9, 2013
- Messages
- 9,955
- Reaction score
- 112
Another common source is CAT5 wire. It's often possible to find some scrap. But purchasing it is cheap at any local hardware store. It comes usually with 5 pairs (or 4) bundled together with an easily removable outer sheath (often grey or blue) - so if you buy just 5 feet of it, you actually have 50 feet of wire. Quite a few commercially made "starters" (or "igniters" if you will) are made from this wire. It's also great for wiring AV bays and such.
Look for it as "phone wire" or "Ethernet wire". Looks kinda like this:
s6
SWEET!!! I just scored a Pile of used CAT5 Cables for free on the side of the Road the other day. I already have plenty, so now I'll have something to do with all these extras.
I suggest a little, simple test when using a length wire of an unknown provenance. Can be done with twisted pair or used two conductor wire. Strip both conductors on one end so you can connect up an ohm meter. Separate the two conductors on the other end. If the ohm meter/continuity tester indicates a short (ie. 0 ohms when it should be infinite) means some of the insulator melted between the two conductors and that length should be discarded. Especially if one is interested in using it for homemade ematches. Now with the options out there for commercial ematches, it's less likely anyone is going to be making them from scratch.
Obviously, if one is using brand new wire and not wire that someone has already blasted 80 amps through an 18ga. nichrome heating element, this test is superfluous. If a sufficient amount of heat is generated along the length of the igniter wire, some melting and contact might occur between the conductors after use that is not easily seen. It's a simple enough to test with a cheap ohm meter that the insulation is intact between the two conductors of leadwire.
BEGINNER IGNITER TIP:
If one dips a batch of igniters and finds out that they just go "POP", blow off some of the pyrogen and don't flare, don't despair. Let 'em "age" a little longer (a few months) or better yet, simply take your fingers and gently bend and crack the pyrogen transversely along the length 3 or 4 times. If you do it carefully the pyrogen will stay on the end. Do that and they'll work.
What happens is when one blasts the igniter with a zillion amps, one spot on the wire may create a little more heat and the pyrogen overlying this spot generates the products of combustion that finishes off the bridgewire before the rest of the wire has heated up enough. The gas from the products of combustion "pops" and blows that little area off the igniter and breaks the wire. Hence one sees an igniter with one small piece of the pyrogen blown off and a broken bridgewire.
Now, when I had a batch of these "poppers" I was trying to figure out what was going on. I was messing with them and connected them up to a partially spent 12V battery to test further. I found out that the nichrome bridgewires gradually heated up and the pyrogen would catch and burn. It occurred to me that something was happening in a segmental fashion when a lot 'o amps passed through that made the igniters "pop". I guessed by cracking the igniter transversely along the length of the pyrogen head that it might allow some of the gas of combustion to diffuse out and allow enough time for with pyrogen to uniformly catch.
Anyhow, if one dips a batch of "poppers" try cracking the pyrogen heads just before putting the igniter in the motor. You might salvage the bunch. Kurt
The other thing is to remember ohms law (E = I*R, or I = E/R). If you make your bridge wires at 1 to 2 ohms, you will limit the current to 12 to 6 amps at 12 VDC and you won't get those poppers that Kurt was talking about. I usually use about 1/2" of bridge wire for smaller igniters (G to J motors), 3/4" to 1" for larger K and up motors. Your pyrogen mix is also important. Slow burning that throw off burning particles work better. I use Magnesium shavings in mine which burn at 5,000 deg and make it look like a sparkler for the 1 to 2 seconds it takes to burn off all the pyrogen.
Trying to make matches is a whole different problem.
Trying to make matches is a whole different problem.
TopRamen
SA-5
- Joined
- Aug 9, 2013
- Messages
- 9,955
- Reaction score
- 112
Just tore open another one(Different Brand), and found the same chintzy wires that are composed of many tiny Filaments.
I'm not in need of any Ignitors, nor did I have any immediate plans to make my own, so I'm just going to leave the rest of my spare CAT5 Cables alone.
Hope this info is helpful to anyone who is considering opening up CAT5 Stuffs to get the Wire.
I'm not in need of any Ignitors, nor did I have any immediate plans to make my own, so I'm just going to leave the rest of my spare CAT5 Cables alone.
Hope this info is helpful to anyone who is considering opening up CAT5 Stuffs to get the Wire.
Last edited:
cavecentral
Well-Known Member
- Joined
- Jul 1, 2011
- Messages
- 3,148
- Reaction score
- 38
Cat5 can be solid or stranded. Stranded is designed for flexible wires. Solid if noy likely to move much.
dmlappert
Well-Known Member
Great service and if you get on their list by ordering, they have sales several times a year.
- Joined
- Feb 3, 2012
- Messages
- 6,349
- Reaction score
- 5,559
Stranded network cable is used for patch cables (RJ-45 plugs on each end), the solid cable is used for in-building runs (punched down to a patch panel). The stuff that you're likely to find at your local store is almost certainly going to be stranded. If you've recently had some kind of network remodeling at your day job, you might be able to get lucky and score some surplus solid cable.
accooper
Well-Known Member
- Joined
- Oct 12, 2009
- Messages
- 920
- Reaction score
- 2
Go Here. It's cheap and will fit fit from a D13 18mm reload to anything bigger. I know cause I've done it!
https://www.pyrodirect.com/Item/015-5000-BLACK26G
Andrew
Similar threads
