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internal heat shielding for electronics

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wwattles

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I'm building a 2-stage rocket that will be airstarted, but I'm wary of trying to run wires along the inside of my rocket, knowing that those wires will be repeatedly exposed to the intense heat and abuse of ejection charges.

Do I need to wrap my wires in anything to protect them? I have at my disposal Kapton tape, Teflon tape, Electrical tape, and a few small-diameter BT's.

When finished, these wires will not be accessible by any means short of cutting open the rocket.

WW
 

BlueNinja

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First, here should be some way to access them so you cna rewire if they get corroded etc.

Second, I'd use teflon tape. I've heard good things about Teflon. Maybe you could use a slitted soda straw to keep the wires together, then wrap that in the teflon and seal off the ends with teflon.
 

teflonrocketry1

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I would use the Kapton tape it should be good to 500 degrees F and stay where you put it. The Teflon tape might be too thin and fray too easily. Electrical tape probably won't take the heat as well.

You could always use Teflon Heat-Shrink tubing. Look at the botton of catalog page 710 for PTFE tubing at:
http://www.mcmaster.com

Or you could get Heat Resistant Sleeving from All Electronics at:
http://www.allelectronics.com/cgi-bin/category.cgi?category=795&item=SLV-2&type=store

Bruce S. Levison, NAR #69055
 

Micromeister

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OR Kevlar braded tubing, I've used this type material in the past for just the application your talking about, running wireing along the inside of a model with pull out plugs.
 

edwardw

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I have run wires inside brass "conduit" The conduit is just the hollow brass rod sold at hobby shops. 3/16 worked for my application. Mine ran through two rings, so I just flared one end and epoxied, and then flared and epoxied the other end. Works great. Silicone covered wires will also withstand the heat - although hard to get a hold of. If weight isn't an issue you could use spark plug wires...

Edward
 

wwattles

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I just found this great stuff at a local electronics supply store. It's a tube of some kind of heat-resistant cloth that is designed to insulate wires in high-temp environments. It's rated to protect from -50C to +560C! My cardboard tubing would burst into flames before that would!

And the best thing of all? It was only $.25 a foot!

WW
 

vjp

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Just an idea-

Why not run your internal wires to terminals on the aft plate/bulkhead/centering ring, and attach your ignitor leads to these terminals. Then, there's no need to worry about frying the wires.

The terminals could be a simple machine screw through the CR, secured with washers and nuts, with the head of the bolt inside the rocket. Washers on both sides, a permanent nut on the outside (epoxied or CA'ed in place to prevent accidental loosening), and an additional removable nut for the igniter lead connection.
 
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