Hi John,
Just getting back to this...
They refer to it as "Bondo for airplanes" - any reason not to use regular Bondo
(I have a can in the garage)?
Thanks!
Adrian
-----Original Message-----
From: roc-chat-bounce@xxxxxxxxxxxxx [mailto:roc-chat-bounce@xxxxxxxxxxxxx] On ;
Behalf Of John Coker
Sent: Tuesday, June 7, 2016 10:54 PM
To: roc-chat@xxxxxxxxxxxxx
Subject: [roc-chat] Re: Epoxy putty
For purely cosmetic filling, I like to use SuperFil. It's two-part and it
cures like epoxy but is very light and doesn't sag so works perfectly for
filling.
http://www.aircraftspruce.com/catalog/cmpages/superfil.php
John
On Tue, Jun 7, 2016 at 9:11 PM, Adrian P. Bailey <adrian@xxxxxxxxxxxxxxx> wrote:
Thanks everyone! The fins are TTW and I used RocketPoxy for the main
construction. It's already flown once successfully without fin fillets
so this would be more aesthetics and aerodynamics than structural,
although we plan to use bigger motors.
I love the rotisserie idea, too! :)
Amazon orders can be weird sometimes. The Rectorseal showed free same
day with Prime but when I added it to the cart the earliest was
Thursday (other items in the same cart are coming today). So, I guess
I’ll have to drive to a hardware store… the horror… ;)
From: roc-chat-bounce@xxxxxxxxxxxxx
[mailto:roc-chat-bounce@xxxxxxxxxxxxx]
On Behalf Of Alexander Jones
Sent: Tuesday, June 7, 2016 11:56 AM
To: roc-chat@xxxxxxxxxxxxx
Subject: [roc-chat] Re: Epoxy putty
Yeah, there is a bit of a whet out problem with it, but if you dip
your finger in a bit of isopropyl alcohol and run your finger along
it, it helps lubricate and slightly softens the putty without
affecting the cure, so you can get okay-looking fillets just doing
that. You can then sand it down fairly easily. I've also used EWF to
add easily sandable material on top of this stuff, allowing you to
shape it down to a nice aesthetic fillet without expending a ton of
effort to sand the epoxy clay. I like to try new techniques with each
rocket's fillets, though, and I think my next one will be using the
John Coker method, using a pretty heavily thickened/filled long cure,
like West System, then use a plastic spoon to remove the excess and
shape it. I would like to try your method, though, too, just letting
gravity do its thing. My only concern is getting it evenly
distributed between fin and airframe, especially on 3-fin models -- I like
the rotisserie idea.
On Tue, Jun 7, 2016 at 11:46 AM, Kenneth Brown <ken@xxxxxxxxxxxxx> wrote:
The problem with putty is that it doesn't whet out to the body and fin
since it's so viscous. I prefer to use a 60min epoxy (longer set times
generally mean a stronger bonding epoxy) filled with microspheres to
thicken it slightly and then put the body on a rotisserie horizontally
to keep the epoxy from sagging. I get very nice fin root fillets this
way. I should add that I will pin the fins in place with a couple of
spots of super glue to hold the fins in place while the epoxy cures.
Ken
On Jun 7, 2016, at 11:38 AM, Alexander Jones wrote:
Adrian, it looks like you can get this stuff at some home depot
stores, apparently in the plumbing section. On another note, I've
had okay results with the loc-tite brand stuff that's also available
off the shelf at HD (I tend to go for the stuff that's wet
applicable, which might explain my success with it re: the brittle
issue), but it really depends how much stress you're planning to put
on the joint. If it's minimum diameter or you're otherwise expecting
super-high accelerations and mach+ speeds, I'd reevaluate it....if
you're staying below mach and you're using a robust fin attachment
like TTW, you should be fine. Also, all the putties are actually
A+B, just some of them combine it into one "log" of putty, with the
A+hardener
in the outside layer, usually the colored layer, then the epoxy is
the core and is usually white or at least lighter-colored....you use
a plastic knife or something to chop off a little section of the log
and just knead it together until it's homogeneous.
On Tue, Jun 7, 2016 at 11:02 AM, Adrian P. Bailey
<adrian@xxxxxxxxxxxxxxx>
wrote:
Thanks Alexander and Mike!
I can’t get the Amazon order to work (and have been using Prime for
years) so they may not have it in stock for same day. They do have A+B epoxy
putty.
It’s for fin fillets and what I’ve read is that some putty is too
brittle and the fillets break off.
From: roc-chat-bounce@xxxxxxxxxxxxx
[mailto:roc-chat-bounce@xxxxxxxxxxxxx]
On Behalf Of Alexander Jones
Sent: Tuesday, June 7, 2016 9:44 AM
To: roc-chat@xxxxxxxxxxxxx
Subject: [roc-chat] Re: Epoxy putty
Adrian, looks like you're in luck, there's a rocketry forum post
where a guy gives a brief review of this exact product:
http://www.rocketryforum.com/showthread.php?74822-Rectorseal-EP-400-Epoxy-Putty-Works-Great!
On Tue, Jun 7, 2016 at 9:41 AM, Adrian P. Bailey
<adrian@xxxxxxxxxxxxxxx>
wrote:
Has anyone used Rectorseal Ep-400 Epoxy Putty, or have other
recommendations? I’m looking for something that Amazon can deliver
today… ;)
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