What are the loc precision type nose cones made of?

What are the loc precision type nose cones made of?

Post by lizardquee » Tue, 10 Oct 2006 09:40:02



Hi,
I was wondering what type of plastic the loc precision nose cones are
made of.  Also, what adhesives can bond these nose cones?
Also, after fiberglassing the air frame, the outside diameter of the
air frame is larger than the O.D. of the nose cone.  How do people deal
with this size difference?  Do they add material to the outside of the
nose cone to compensate for the difference?  (like fiberglass or bondo
the the bottom of the cone?)  I am talking about a 1 or 2 mm
difference.  My concern is that this will generate drag and any
materials will no adhere to the material that the cone is made from.
Thanks.
 
 
 

What are the loc precision type nose cones made of?

Post by Doug Sam » Tue, 10 Oct 2006 10:48:49


Quote:

> Hi,
> I was wondering what type of plastic the loc precision nose cones are
> made of.  

Teflon? :)  (Sorry, Barry.)

Quote:
> How do people deal with this size difference?  

I scuff up the bottom couple inches of plastic real well - 100 or even
80 grit paper - put a couple wraps of tape around the base so the cone
fits real tight in the 'glassed airframe, then screed some FNF onto the
cone.  Once it's applied, remove the cone from the airframe while
turning it, then clean the excess off the tube.

While LOC tubes have a reputation for not holding paint, IIRC I used FNF
on my LOC cone to fill the seam and have had no problems.  So the above
technique should work.  I've also used the same technique with Bondo
(not on LOC cones) so you might try that if you're hesitant about using FNF.

 > My concern is that this will generate drag ...

For me, it's strictly the aesthetics - it doesn't need to be fast, but
it's gotta look fast :)

Doug

 
 
 

What are the loc precision type nose cones made of?

Post by Steve Humphre » Tue, 10 Oct 2006 11:24:34


Quote:

> I was wondering what type of plastic the loc precision nose cones are
> made of.  Also, what adhesives can bond these nose cones?

Polypropylene. "Nothing" sticks to them. :-)

This topic has been discussed before in this forum, so searching through
the r.m.r. archives will give you some good advice. Here's the first hit
from the search of the terms "nose cone flame":
   http://tinyurl.com/npnae
Scroll down through the messages for some good tips on finishing LOC and
similar nose cones.

Why "flame"? It turns out a good way to prep the nose cone is to run a
torch over the surface. I kid you not. The goal is to oxidize the
surface, not melt the nose cone. Rough sanding also helps, by giving
some tooth for paint and adhesives to grab onto.

I suggest priming the nose cone first, following these tips. Then apply
a filler (fill'n'finish, epoxy filler, etc.) to build up the nose cone
to match the fiberglassed airframe.

--
Steve Humphrey
(replace "spambait" with "merlinus" to respond directly to me)

 
 
 

What are the loc precision type nose cones made of?

Post by Darrell D. Moble » Tue, 10 Oct 2006 13:32:56


Quote:

> I was wondering what type of plastic the loc precision nose cones are
> made of.  Also, what adhesives can bond these nose cones?
> Also, after fiberglassing the air frame, the outside diameter of the
> air frame is larger than the O.D. of the nose cone.  How do people deal
> with this size difference?  Do they add material to the outside of the
> nose cone to compensate for the difference?  (like fiberglass or bondo
> the the bottom of the cone?)  I am talking about a 1 or 2 mm
> difference.  My concern is that this will generate drag and any
> materials will no adhere to the material that the cone is made from.
> Thanks.

I always used a couple of heavy coats of primer on the nosecones to take
care of that.  I would sand the nosecone with 60-80 grit sandpaper to
make it really rough, and load it up with Kilz primer.  The rough edges
left by the sandpaper really grabbed the primer.  It looked funny the
first couple of coats -- like a sweater!  But the paint NEVER peeled off.

--
Rocketry Planet hobby rocketry news, feature articles, news archive,
discussion forums, live chat, free auctions, launch calendar and the
largest collection of web links anywhere!

http://www.rocketryplanet.com

 
 
 

What are the loc precision type nose cones made of?

Post by Darrell D. Moble » Tue, 10 Oct 2006 13:40:57


Quote:

> Polypropylene. "Nothing" sticks to them. :-)

Automotive paint companies make special primers for this type of
plastic.  This is similar to the type of plastics used to make
automobile interior trim.  Replacement parts are usually only sold in
one color, so autos damaged in wrecks have to have these
one-color-fits-all parts painted to match the existing interiors.  In
order for the paint to stick, they use the special primers.

These special primers are available anywhere autobody paint and supplies
are sold in spray cans or some vendors have pints and quarts.  All it
takes is a few light coats after wiping the part with the right prep
solvent.  I believe one company that makes the primer is MarHyde.  But I
am pretty sure 3M, PPG, DuPont and Ditzler have their own brands.

--
Rocketry Planet hobby rocketry news, feature articles, news archive,
discussion forums, live chat, free auctions, launch calendar and the
largest collection of web links anywhere!

http://www.rocketryplanet.com

 
 
 

What are the loc precision type nose cones made of?

Post by lizardquee » Tue, 10 Oct 2006 17:59:47


Thanks,
These are great ideas-I think I'll try them all.  Not on the same
rocket of course.
I appreciate the help.
 
 
 

What are the loc precision type nose cones made of?

Post by Chuck » Wed, 11 Oct 2006 10:05:38


I got so tired of the endless prep work required on ACE/LOC/PML/etc
plastic nose cones that I finally just started using fiberglass for
all of my HPR rocs.

Everything I build is scratch anyway so the switch wasn't that big of
a deal for me.

I suspect that the rocket companies could make a few extra bucks by
offering fiberglass cones as an upgrade to their kits.

Now, for my upcoming L3 I am planning a rocket with no nose cone at
all!  The motor mount will be supported by the TTW fins and the air
will flow right through the airframe.  The recovery system will be
contained in a separate pod.  I'm still working on the design but
think F-100 styling.

Chuck W
www.atomicturtle.net

Sharc, NAR Section 613
www.flysharc.org

Sharc, we fly rockets so you don't have to!

 
 
 

What are the loc precision type nose cones made of?

Post by mark.simp.. » Sat, 14 Oct 2006 08:16:06


Auto fascia pieces are treated similarly. They call it corona discharge.
It sounds more impressive. ;-)

Mark Simpson

Quote:

> Why "flame"? It turns out a good way to prep the nose cone is to run a
> torch over the surface. I kid you not. The goal is to oxidize the
> surface, not melt the nose cone. Rough sanding also helps, by giving
> some tooth for paint and adhesives to grab onto.

 
 
 

What are the loc precision type nose cones made of?

Post by mark.simp.. » Sat, 14 Oct 2006 08:17:42


I still have one more mint condition traffic barrel. ;-)

Mark Simpson

........

Quote:

> Now, for my upcoming L3 I am planning a rocket with no nose cone at
> all!  The motor mount will be supported by the TTW fins and the air
> will flow right through the airframe.  The recovery system will be
> contained in a separate pod.  I'm still working on the design but
> think F-100 styling.

> Chuck W
> www.atomicturtle.net

> Sharc, NAR Section 613
> www.flysharc.org

> Sharc, we fly rockets so you don't have to!