Electric Match Kit Instructions
- 50 RESISTANCE ELEMENT CHIPS
- 50+ FT TWO CONDUCTOR LEAD WIRE
- 1 BOTTLE CARBON BASE "A" MIX
- 1 PACKET "B" OXIDIZER
- 1 MIXING STICK
Also required (not supplied) M.E.K. or Acetone and soldering supplies
Mixture(s) may be harmful if swallowed - Keep from reach of children; Flammable keep from heat or flame; Use in well ventilated area; Contains lacquer and solvent- avoid breathing of vapors. Consult MSDS on this product before using.
Inhalation: Remove to fresh air. Skin Contact: Wash with hot soapy water. Eye Contact: Flush with water for 15 minutes & call your physician. Ingestion: Induce vomiting, contact physician immediately.
This Field Kit is used to construct an "electric match" (igniter) for model rockets and similar remote use, requiring a DC voltage charge to initiate.
The prepared leads - ready for dipping consist of two types of wire; The lead wire consisting of 22 awg or smaller twin lead/solid "zip cord" and the element wire "chips" that require soldering to the lead wires.
The smaller the diameter the element is, the less voltage it will require for proper heating and ignition. You will find that the most reliable igniters are those containing resistance elements of 30 awg or finer (down to 50 awg for low voltage types). The voltage required to ignite the pyrogen will depend on the element type and gauge.
This field kit comes with 38 awg element wire chips for reliability. The heavier gauge resistance wire will "pre-heat" a fraction of a second longer than a smaller gauge and supply more molten metal upon burn-through. The delay is not noticeable. Generally, a 12-volt automotive battery is common in high power rocketry at appropriate distances. Here, as little as 1.5 volts (alkaline AA battery) is required for applications such as remote control on-board pyrotechnic charge activation (recovery system, tracking smoke, etc.). Although as little as an AA battery may be used, we recommend a 9-volt battery for short line on-board applications and higher voltages as the length of firing lines increase due to increased firing line resistance.
PROCEDURE / WIRE PREPARATION
The following soldering steps are done before entering the field and coating with the pyrogen. It is much more difficult to solder the leads in the field. Solder the end opposite of the color band on the chip, to the leads! The color band end is the end with the resistance wire and the end that is dipped in primer.
- The lead wire supplied with this set is in random lengths. There is more than enough to make 50 one-foot-long leads. Cut them and strip off approx. 1/8" insulation from one end.
- Dip the bare leads into Ruby Fluid Flux (Soldering Zinc Chloride Solution, can be found on Google).
Chips; Dip the tinned leads once again in the Soldering Ruby Fluid, tin the tip of the soldering iron, slip a "chip" (the end opposite the color band) between the copper leads, and apply heat to each lead using the tinned soldering iron. The solder will flow from the soldering tip, over the wire and onto the chip thus soldering the piece. Repeat this on the other side. This only takes a second. DO NOT hold a hot iron on the chip and apply the solder! This will de-solder the element and damage the chip.
- Clean the soldered element ends with M.E.K. or Acetone to clean any residual flux from the surface and allow to dry before dipping in pyrogen. Residue flux may cause ignition failure.
- Test the igniters for continuity and resistance with an ohms meter. Most commercial igniters of this type will read between 1 and 2 ohms after pyrogen is applied. If there is no continuity, the chip has been damaged and will not fire.
PROCEDURE / DIPPING THE PREPARED IGNITERS
- Slowly add enough acetone or M.E.K. to the glass bottle to make a paint-like slurry. Allow to stand for a couple of hours, adding more solvent to keep it at a paint-like slurry as the solvent absorbs into the fuels and activates the binder. Do not add too much solvent!
- If the oxidizer in the packet is lumpy, crush between the fingers to make a fine powder. Add the oxidizer packet to the glass bottle and mix again. It should be the viscosity of house paint. If it is too thin, it will not coat properly (all the solids now on the bottom of the bottle instead of being suspended in the slurry). Allow it to evaporate until proper viscosity is achieved. If it is too thick, the pyrogen will not coat smoothly and "glob" on the chip. If this is the case, add slightly more solvent a few drops at a time, until the correct consistency is obtained. Mix often during use.
- Dip the tip of the element chip, half the length of the chip, into the prepared pyrogen slurry. Allow to dry thoroughly before use. This will take about an hour or so in warm dry climates, longer in colder, moist and/or humid climates. Be sure they are completely dry before using. A final coat of Nitrocellulose lacquer (Part #CH8197) is recommended but not mandatory because the igniters are - being used in such a short length of time after construction. A thin coat of pyrogen is all that is necessary. You can thin the pyrogen with a couple of drops of Acetone, as it thickens when using. NOTE: Once mixed, use it up as quickly as possible as it will dry out in a few days, even in a properly closed bottle. Once dry, it is highly flammable and friction sensitive. Do not try to pry out or break up a hardened mixture!! It cannot be re-dissolved into a useable slurry once hardened. Consult MSDS for information about proper disposal. DO NOT incinerate the unused and/or hardened mixture while in the bottle. Fill the bottle with water and allow it to decompose with time.
Author: Gary Purrington