Heat-PROOF engine mount tubing?

how about metal? Coat the inside with heavier weight tin foil or something... Its definately cheaper than nomex paper.

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"Gordon S. Hlavenka" < snipped-for-privacy@crashelex.com> wrote in message
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There is high temperature foil "tape" for fireplaces and chimneys. Self adhesive and UL rated to several hundred degrees (don't have it in front of me).
Tom K

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Thomas Koszuta wrote:

You can get it at Home Depot or Lowes.
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Fred, thanks for the Hibachi pointer; that's probably what's going on. I'm firing C6-3 engines in Estes BT20; I think I'm going to try the popcan technique Terry and Chuck mentioned, with some JB Weld. Steve's Nomex paper idea sounds interesting, too.
I don't want to put in a baffle as the whole idea is to try and come up with a zero-maintenance method. Plugged baffles are exactly the kind of thing I'm hoping to design out.
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Keep in mind that the flame path is coming up to temperature at about the same time as the event is over- the temperature is spiking. I wonder if you're seeing charring near the end of the tube from unconsumed ejection particulate finally mixing with a suitable atmosphere?
At any rate, I vote for the lightweight heat shield too :-)
CA glues will produce noxious fumes when heated and aren't heat resistant in this range anyway. Epoxy will soften but the heating event duration is so short it won't occur in this range, still over time there will be a degradation of it's surface so that negates the zero maintainance you're going for.
Mike Doyle
Gordon S. Hlavenka wrote:

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The ejection charge is not roasting the stuffer tube - the delay afterburn is roasting it. bad on all motors but worst on special composite motors. Also the most vulnerable tubes are those with thin walls like standard Estes BT-5, 20 and 50. BT-55 thickness is a bit more. MRC tubes were the thinnest ever.
Google Hibachi Effect.
http://www.google.com/search?sourceid=navclient&ie=UTF-8&rls=GGLR,GGL ...
http://www.apogeerockets.com/education/newsletter28.asp
-Fred Shecter NAR 20117 http://search.ebay.com/_W0QQfgtpZ1QQfrppZ25QQfsooZ1QQfsopZ1QQsassZshreadvector
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How about alum cigar tubes?
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snip
We've coated the inside of the stuffers with yellow glue on some and ca on others or both. Both have been effective. Where the burn through is occurring (not all the way up) you could also add 2 or 3 plys outside the area with additional layers of tubing and coat that. It will add a small amount of weight, so check the cg.
We've got several birds with 20+ flights on them using this method and still no signs of burn through. One thing to watch for is crud build up. I use a standard bottle brush for that.
Randy www.vernarockets.com
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