# First Scratch Ignitors

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#### rbeckey

##### Well-Known Member
I got some pyrogen from Rocketflite and using some scrap cat5 cable, made E-F-G ignitors. I had some 32 ga. nichrome and made solderless ignitors from instructions found online. I made 16 and tried 3, and all three lit ASAP and burned big.
What is the shelf life of an assembled ignitor? I will store them in a ziplock EMD bag, as I understand they are more impervious to moisture.

#### swimmer

##### Well-Known Member
rbeckey,

I also dipped my first dozen tonight. I will test fire several tomorrow.

I've had some purchased ignitors for over two years and they fire just fine, no problem.

I've heard of ignitors that will fire under water.

I haven't made my own wires yet but I'm waiting on nichrome wire from edwardw. You know that wire you get with a garage door opener for the control wiring? I bought two large rolls at a garage sale and the twin conductor will make fine ignitor wires.

#### rbeckey

##### Well-Known Member
Cat5 cable is what is used for computer networking. It can be purchased by the foot at Lowes, etc. It has four twisted pairs of bell wire, perfect for ignitors. I am sure the garage door control lines are similar stuff. Actually making the ignitors is a little tedious and time consuming, but it seems worthwhile compared to the cost of store bought.

rbeckey,

#### daveyfire

##### Piled Higher and Deeper
What do you guys use for the conductive dip, besides what Igniterman (used to?) sell? I've been looking for a good conductive dip mix. I don't think the current requirement on a dipped igniter is any worse than the requirements of a wrapped igniter, since you're dealing with a lot of nichrome compared to the dip.

#### jetra2

##### Well-Known Member
Curious...

A conductive dip is basically the same stuff that's used on Copperheads? I would definately be most interested in getting my hands on some of it if it is. It would save me a lot of time. Then I might could make two different kinds of igniters, one with the conductive dip, the other the "normal way."

Jason

#### BlueNinja

##### Well-Known Member
yea it's gotta be, thats the only way to bridge teh copper unless there is some bridge wire... doubt that though.

#### limd21

##### Well-Known Member
I make conductive dip out of graphite powder mixed with clear nail polish. The graphite powder is sold in hardware stores as a dry lubricant (e.g. for locks). Most nail polish is nitrocellulose based, which is very flammable all by itself. I've heard of others using a powder called "conductive lamp black", but I cannot think of a cheap source of such material.

#### llickteig1

##### KLOUDBusters Chief Logistician
What is the shelf life of an assembled ignitor? I will store them in a ziplock EMD bag, as I understand they are more impervious to moisture.
I don't have any empirical evidence as yet, but I have been told that with the solderless ignitors there could be some corrosion between the conductors that could impede their ignition. A don't doubt this, particularly since the components are made from different materials (copper and nickel-alloy). I would say that a good 12v launch system would be a little more forgiving in this regard.

Storing in a moisture-proof bag is important. I personally don't make a lifetime supply at one sitting. I make maybe 50 and then share them as needed at launches and that'll last me about a flying season. When I get low, I make more and be sure to use the old ones first. If you have any doubts, fire a few to make sure they're still good. Also, handle your ignitors with care as the pyrogen is brittle and can flake off if it gets broken. One resource I have suggests storing your ignitors in small diameter mailing tubes for protection.

If you wrap your own nichrome and make your own pyrogen, you can make reliable ignitors for pennies. No more $1 or$1.50 ignitors from vendors.

Swimmer and Blue_Ninja_150: look me up at a launch soon and I'll show you a couple of tricks to making various sizes of wrapped ignitors for a range of motor sizes.

--Lance.

#### Stones

##### Well-Known Member
Originally posted by jetra2
...
Also, I e-mailed Rocketflite a while back and they told me that the nichrome they use is .056" diameter.
Those must be awful big igniters. That's like 15 ga. wire! I'm a little lost. Can we verify what most are using here for the nichrome? Either by decimal or gauge size. So far, 32 gauge (.008) sounds about right. At least for igniters in the E-G range.

#### jetra2

##### Well-Known Member
I would say you're right, Stones...I just checked the e-mail I got from them, and they told me they use .056 diameter wire for the element. Maybe he typo'd and meant .0056?

Jason

#### aksarben10

##### Well-Known Member
Originally posted by Stones
Those must be awful big igniters. That's like 15 ga. wire! I'm a little lost. Can we verify what most are using here for the nichrome? Either by decimal or gauge size. So far, 32 gauge (.008) sounds about right. At least for igniters in the E-G range.
I have tried several different gauges of wire for my ignitors and 32 gauge is my favorite for high current. 30 works great but I found it a bit to stiff and 36 was just too wimpy, fired great but was a pain to wrap. Smaller gauges are good if you are going to solder and make chips and low current matches.

My ignitors use the wire wrap technique as described on Info-Central.

Scott

#### edwardw

##### Well-Known Member
I use 36 guage for everything from G to M motors. The pyrogen I use just happens to be the propellant I use (KNCP) so some 36 guage and a slug of pyrogen light everything right up. I usually make the slugs round cylinders to fit the core, from 1/4" to 1" and about 1" long.

Edward

#### jerryb

##### Well-Known Member
Originally posted by Blue_Ninja_150
Hmmm... haven't checked there, will try to get out and look. I'll probably just do the 110ft-\$15 thing though.
make SURE that the cat-5 your looking at is SOLID... and not stranded cat-5e not sure if the stranded will make good ignitors..

Cat-3 cable is a teensie bit smaller... but much cheaper... usually 2 pair per cable...

you could always do an Ebay search for Patch Cables...

I've bought 25 foot cables there for a buck a piece before.. you just have to pay the shipping...

#### BlueNinja

##### Well-Known Member
it is the CAT5 stuff, i asked to make sure it wasnt 5e.