[RocketsNW] Fins on a Minimum Diameter

[Greg Clark]

I used chopped Kevlar in my fillets, but just about any 'chopped'
material will add some needed strength.  For my 3-4" rockets, I lay
out the epoxy, cover it with a plastic sheet, and "form it" with a
piece of  3/4"  PVC pipe.  Result?  Perfect fillets!

Important, since sanding kevlar is no fun...

-- Greg

On Sat, Jan 30, 2010 at 7:12 PM, jman13 at gmail.com <jman13 at gmail.com> wrote:
> Hey Scott, thanks for the advice. I'll try it with the casing in.
>  You said you used epoxy mixed with milled fiberglass: two questions, how large did you make your fillets? Any larger than normal? Also, I've heard of people using fiberglass boat-body sealent as fillet material, have you or anyone else heard is that's a successful method?
>
> Thanks,
> Julian
>
>
>
> -- Sent from my Palm Pre
> Scott Berfield wrote:
>
> I just got the fins on my 75mm min diameter. I cut slots and stuck in a
>
> plastic wrapped motor case. Tacked the fins into the slots with epoxy,
>
> butted up against the case. Pulled the case. Added fillets to the fins with
>
> epoxy mixed with milled fiberglass. Then applied two layers of glass, one
>
> halfway and one tip to tip. Seem rock solid.
>
>
>
> -----Original Message-----
>
> From: rockets-bounces at rocketsnw.com [mailto:rockets-bounces at rocketsnw.com]
>
> On Behalf Of Julian Picard
>
> Sent: Friday, January 29, 2010 5:53 PM
>
> To: rockets
>
> Subject: [RocketsNW] Fins on a Minimum Diameter
>
>
>
> 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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