[RocketsNW] Fins on a Minimum Diameter

[Christopher Guenther]

That is why I remove the coupler with the waxy freezer paper before curing
in the oven.   LOL

On Tue, Feb 2, 2010 at 11:10 AM, Greg Deputy <greg at blastzone.com> wrote:

> One other tip.  Use parchment paper, rather than wax paper.  Parchment
> paper
> (for baking) is impregnated with silicone and epoxy will not stick to it,
> and the paper is good for use in the oven.  Wax paper is not so good in the
> oven, wax can melt out, epoxy can stick to it, etc.
>
> -----Original Message-----
> From: rockets-bounces at rocketsnw.com [mailto:rockets-bounces at rocketsnw.com]
> On Behalf Of Scott Berfield
> Sent: Tuesday, February 02, 2010 10:33 AM
> To: 'Christopher Guenther'; 'Julian Picard'
> Cc: 'rockets'
> Subject: Re: [RocketsNW] Fins on a Minimum Diameter
>
> I recommend that if you plan on using the kitchen oven, you wait until the
> wife is out.
>
> -----Original Message-----
> From: rockets-bounces at rocketsnw.com [mailto:rockets-bounces at rocketsnw.com]
> On Behalf Of Christopher Guenther
> Sent: Tuesday, February 02, 2010 10:03 AM
> To: Julian Picard
> Cc: rockets
> Subject: Re: [RocketsNW] Fins on a Minimum Diameter
>
> I wrapped a coupler with a waxy freezer paper and went completely through
> the wall to the paper and 30 minute epoxied the fins into place.  When the
> epoxy had set enough to hold and still be a tad pliable I removed the
> coupler with the waxy paper then popped the fincan into the preheated oven
> at 250 for about 30 minutes.  (be sure to constantly check to make sure you
> are not starting to darken the tubing or smoking)  If the fincan is to long
> for your oven door to shut that is fine just make sure you have lots of
> ventilation in your kitchen.  Then after it has been oven hardened I
> started
> layering epoxy mixed with milled fiber (you can get milled fiber from Tap
> Plastics) along the fin root to even it out and to build the curve from the
> fin to the body.  (Fiber Glass and Carbon Fiber do not like to form to
> sharp
> corners very well.)  With each layer I oven hardened again, and remember to
> give a light sanding in beteween each layer it will help smooth out any
> dimples/bubbles etc... and make it easier for the next epoxy layer to bond.
> After I reached a point that I was satisfied with my layered curve I spread
> a layer of epoxy from fintip  to fintip and set my Fiber Glass in place.
> (remember to measure twice and cut once leaving at least 1/2 an inch all
> around as in my experience some fiber materials out there do shrink as the
> epoxy sets)  Then when that has set start the next Fintip to fin tip and so
> on until you have done them all the way around at least once, more is ok
> but
> remember the more you add extra the heavier your rockets aft end will be.
> When the last fintip to fintip has set I oven harden again for about 30
> minutes.  After that I gave it a light sanding to smooth it out and add
> another thin layer of epoxy, oven harden and repeat until I  had reached a
> smoothness I liked.  Unless you have a bad flight there will not be much
> that will phase those fins.  (unless you throw in a motor made by Mike F.
> that is  LOL)
>
> Chris Guenther
> NAR L2
>
> On Fri, Jan 29, 2010 at 5:53 PM, Julian Picard <jman13 at gmail.com> wrote:
>
> > Hello everyone,
> >
> > My name's Julian Picard, and I'm new to the list. I'm here at the
> > University of Washington, and I'm working on a building a 54mm minimum
> > diameter, and I'm looking for suggestions on how to better attach the
> > fins.
> > What I did before is to make shallow fin slots and do some initial
> > gluing, and then solidly glassing (or with carbon fiber) the fin can.
> > I'm using a pre-glassed phenolic tube, with G10 fins.
> >
> > Thanks so much for you help!
> > Julian
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> >
> >
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