Among the projects I have going on right now (kitbash with a Estes Stormcaster, clone of a Centuri Gabriel, and finishing a Quest Shuttle Intrepid) I am starting the prelim work on a V-32 designed by Melville Grant Boyd and found in American Aircraft Modeler. In the description it suggests coating a inner shroud at the engine exhaust with Centuri Flameproofer. Does anyone have any suggestions for this "flameproofing"? The engine is so far recessed that the shroud is there to protect the inner walls of the BT. I had thought about not using the shroud and coating the BT with something but I think the shroud would add to the appearance of the rocket in a very good way. The dry-fit mock up I did was kinda neat looking with the engine a good 3/4"-1" recessed into the BT and the shroud in place.

The other issue I face is with adding about an ounce of weight to the balsa nose cone. The article says to use nails, which I think will work and then I can just fill-n-finish the small nail head holes.

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Kurt Knox
NAR #93503
MASA section 576
SAM #0316

I think the old flame-proofer was powdered ASBESTOS mixed in clear butyrate dope.
Not exactly stuff you would find commonplace ANYWHERE anymore....

Aluminum foil attached to an area with CA would probably work as well.

An example that someone suggested on another rocket forum in the past that absolutely would NOT work for flame proofing is Automotive Rubberized Undercoating. This was a moronic suggestion and probably would act as a flame-ENHANCER not proofer as this stuff is mostly a tar-like PETROLEUM compound mixed with a rubber substance....NEITHER of those have ANY flame-retardant properties whatsoever. I think this clown may have been trying to enduce someone into creating a flying fireball as some sort of warped joke.

The best thing for adding nose weight to nose cones is fine lead shot (#7, #8, or #9 shotgun pellets) mixed with epoxy...it is very dense and stays in place. Not sure I would want pointed steel anything buried point first in a soft balsa nose cone. That sounds like an accident waiting to happen.

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I've got half of an original Centuri Gabriel kit. I may have to get in touch with you for some measurements one of these days if I can't find them online.

I've seen several remedies for "flameproofing". I've used a thin coat of glue, white for small rockets and epoxy for larger. I've seen folks paint the inside with aluminum paint, and I've seen people line the inside with aluminum foil...not sure if they glued it in or if it was purchased with a sticky back. I've also seen people use dope, colored or clear. All were successful at keeping the end from getting roasted, BTW. However, YMMV.

I've heard people talk about using silver trim monocote, but I think it's just colored plastic and probably wouldn't work any better than a coat of glue or a thick coat of silver dope.

I'd love to see that flight...as long as it isn't my rocket.

Two suggestions I would make.

One, forget the flameproofing. Go with a BMS or Totally Tubular heavy duty foil lined motor tube. A lot less trouble.

Two, contact SEMROC I think they may have the laser cutting file for the fins.

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I thought of the epoxy and maybe just yellow glue but am still looking at options. I need to keep the weight to an absolute bare minimum in the aft end so I am not sure about gluing any liners and such on the shroud.

I had thought about drilling out a core in the nose cone so I could get some weight to the tip, or very near it, but I like the idea of keeping it intact and the small brads would keep the weight at the very tip which is where it is needed most. Still thinking.

Here's a quick shot of the BNC-60AH, BT-60, & 24 of the 32 fins 1/32" x 1/4" x 2 3/4". The tube is already marked for all the "finlets".

Attached Thumbnails

   

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Kurt Knox
NAR #93503
MASA section 576
SAM #0316

Hey zep do you have the decals for the Gabriel? The decals are the one thing that I am missing but I have the rest of the parts which I ordered from Semroc.

I am guessing on the fin dimensions, I took them off the scan from jimz? or yorp? not sure which. I am going to contact Semroc and see if they have the exact ones... I know Carl gave me some of the info I needed for the parts but he had mentioned he could not find the fins online.

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Kurt Knox
NAR #93503
MASA section 576
SAM #0316

I still have my original bottle (dried hard as a rock by now) of Centuri Flameproofing Solution around here somewhere circa 1970 or so. All it is is a Sodium Silicate solution.

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I have them, but I don't have a way to scan them right now because I still haven't bought another SCSI card for the scanner. There is some white in the decals, so you'd have to use an ALPS to make some anyway.

Yeah I heard there was some white in them. Phred at Excelsior said he would take a whack at 'em if he could get a scan of them. I would gladly pay him for the set, sounds like his stuff is very good.

If you could just give me the dimensions that would be enough, I don't need an actual scan. No worries though if you can't find the time or the parts, I feel pretty good that I am in the ballpark with size.

__________________
Kurt Knox
NAR #93503
MASA section 576
SAM #0316