[roc-chat] Re: Need advice for Fin Repair, Large Rocket
- From: Gregory Lyzenga <lyzenga@xxxxxxxxx>
- To: "roc-chat@xxxxxxxxxxxxx" <roc-chat@xxxxxxxxxxxxx>
- Date: Tue, 12 Aug 2014 21:51:37 -0700
I thought of this thread today when I saw a guy wearing a T-shirt that said,
"It's not rocket surgery!" ;-)
----------------------------------------------------------
Gregory A. Lyzenga <lyzenga@xxxxxxx>
Dept. of Physics, Harvey Mudd College (909) 621-8378
Claremont, CA 91711-5990 mobile (626) 808-5314
> On Aug 12, 2014, at 9:41 PM, "Adrian P. Bailey" <adrian@xxxxxxxxxxxxxxx>
> wrote:
>
> I’m new to rocketry but I’ve done a lot of other kinds of scratch building
> and repairs over the years. I find epoxies do extremely well if they are
> reinforced with something (e.g. a small piece of flat carbon fiber rod across
> the joint or place where the stress will occur). I think Kurt is saying the
> same thing… ;)
>
> From: roc-chat-bounce@xxxxxxxxxxxxx [mailto:roc-chat-bounce@xxxxxxxxxxxxx] On
> Behalf Of Kurt Gugisberg
> Sent: Monday, August 11, 2014 7:45 PM
> To: roc-chat@xxxxxxxxxxxxx
> Subject: [roc-chat] Re: Need advice for Fin Repair, Large Rocket
>
> You could also do a, more-or-less, surface mount fin. Glue it back in place
> where it broke off, clean the paint off of the tailcone and fin, and epoxy
> fiberglass fillets about an inch up on each side. I know that people say
> that epoxy won't stick to the plastic tailcone, but if you rough it up with
> 60 grit sandpaper , it will hold on pretty well. I have actually done tip to
> tip fiberglass on my LOC 7.5" V2 and it holds together just fine. You could
> also drill and epoxy wood or metal pins to hold the fin in position but I'm
> not sure if that is really necessary.
>
> Kurt
>
> On Mon, Aug 11, 2014 at 4:58 PM, Steve Jaben <smark.jaben@xxxxxxxxx> wrote:
> This is a loc V2, 7.5" diameter stretched out. I broke a fin at the Saturday
> launch. You can see pictures on Rocketry forum:
> http://www.rocketryforum.com/showthread.php?68463-Fin-Repair-Suggestions-Needed-for-Large-Rocket
> The tailcone is made of polypropylene. The fin tabs go through the wall and
> attached to the motor tube. There are two centering rings, one above and
> below the fin tab that is glued to the fin tab and to the motor tube. Epoxy
> doesn't really stick to poly propylene, so attaching extra centering rings
> really holds the fin to the motor tube. I don't see any other way to fix
> this, other than to cut a large window out of the polypropylene tailcone,
> cutting out the old fin tab, and then gluing the whole thing back up with a
> new fin. Getting the window of poly propylene to stick back in might also be
> a challenge. The fins really don't attach to the tail cone because of the
> polypropylene. Any other ideas or thoughts? And buying a whole new tail
> section is not really what I had in mind :)
>
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