[roc-chat] Re: Need advice for Fin Repair, Large Rocket
- From: "Adrian P. Bailey" <adrian@xxxxxxxxxxxxxxx>
- To: <roc-chat@xxxxxxxxxxxxx>
- Date: Tue, 12 Aug 2014 21:41:10 -0700
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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