Poly fuse, bonding formers in place with epoxy?  
View related threads: (in this forum | in all forums)

Tower Hobbies
Enter up to 4 keywords or Tower stock numbers
Logged in as Guest



Users viewing this topic: none
  Printable Version
       

All Forums >> RC Airplanes >> Composites Fabrication And Repair >> Poly fuse, bonding formers in place with epoxy?
Page: [1]

Login
Message << Older Topic   Newer Topic >>
Poly fuse, bonding formers in place with epoxy? - 3/4/2003 2:59:03 AM   
Kelly W



Posts: 869
Joined: 1/21/2002
From: Delta, BC, CANADA
Status: offline 		Hi guys, I'm, new to poly fuselage work.

I'm building a Yellow Aircraft F-18 (the small one) and I'm ready to glue the internal formers into the poly fuse. Some say 30min epoxy will work, some say to use Yellow's 'stablit', and some say to use poly resin. Any opinions / tips would be appreciated.

Thx,
KW

_____________________________

Kelly Williams, GTBA #1969
       Post #: 1

Poly fuse, bonding formers in place with epoxy? - 3/6/2003 12:59:16 PM   
Jimbonk


 

Posts: 76
Joined: 2/24/2003
From: Farmington, CT, USA
Status: offline 		Kelly, Polyester Resin isn't great as a strucural adhesive, I'd go for the 30 min Epoxy or the Stabilit. Just remember to rough up the area where you are going to bond in the former with sandpaper ( like 80 grit ) . If you go with the 30 min Epoxy you might have to add a filler after you mix the epoxy together to thicken it up so it does not run. ( Cabosil, Aerosil, Microballons)

My preferred method for bonding in formers follows ( assuming an unpainted fuse ) after fitting the former in place, wrap a pc. of tape around the Outside of the fuse to mark where the former sits, now you can remove the former and smear some epoxy around the inside of the fuse , using the tape as your guide. Now you put the former back in and make a nice fillet on the side you can get to.

Jim B

(in reply to Kelly W)
       Post #: 2

Poly fuse, bonding formers in place with epoxy? - 3/6/2003 6:00:36 PM   
Jetman007



Posts: 295
Joined: 1/7/2002
From: Spring Lake, MI, USA
Status: offline 		I built one of these and used small strips of 6 oz glass coated with 30 minute epoxy to hold the formers in place. Follow Jim's suggestions above for preparation. Add the strips of glass after epoxy is in place and then brush on a little more epoxy to ensure the cloth strips are saturated.



_____________________________

Art Gajewski

(in reply to Kelly W)
       Post #: 3

Poly fuse, bonding formers in place with epoxy? - 3/6/2003 9:11:03 PM   
Kelly W



Posts: 869
Joined: 1/21/2002
From: Delta, BC, CANADA
Status: offline 		Thanks for the tips guys.

Historically, I tend to prefer using slow curing epoxy for this kind of work. I was mainly concerned that the resin wouldn't cure or bond well enough to the poly surface due to chemical incompatibility. It sound's like this is only an issue when using polyester resin over an epoxy impregnated surface.

The tip about using tape on the outside on a non-painted fuse is good, as apposed to a felt marker that could bleed through paint if not sanded off completely... :

Thanks again,
Kelly

_____________________________

Kelly Williams, GTBA #1969

(in reply to Kelly W)
       Post #: 4

Poly fuse, bonding formers in place with epoxy? - 3/6/2003 10:24:03 PM   
FLYBOY



Posts: 8692
Joined: 1/7/2002
From: Missoula, MT, USA
Status: offline 		Good tips but don't use micro balloons for this. they are a filler and weaken the glue. Cabosil and Cotton flox are good for adding streangth and filling. If you just want something filled but no streangth added, then use micro.

As stated, make sure you rough up the inside good. Not just a little.

_____________________________

Fly it till the wings come off.

(in reply to Kelly W)
       Post #: 5

bonding cements - 3/7/2003 1:33:24 AM   
Kelly W



Posts: 869
Joined: 1/21/2002
From: Delta, BC, CANADA
Status: offline 		I tend to use milled fiber in gap filling situations wherever possible. It tends to stay put and not run from gravity like the microballoon mix will. I used MF with 30 min epoxy on all the internal formers in my Hotspot. If used right It'll leave a nice gentle fillet, easily covered with lightweight cloth later.

As far as roughin' up, I usually sand until I start to feel the glass weave coming out. That seems to give an adequate surface for bonding. It allows the epoxy to penetrate and grab better. Of coarse since the Poly had wax in it, I'll need to wash it with Acetone after sanding.

All n' all, I agree with Jim's note about Poly not being a very structural adhesive. On top of that, there was the question of compatibility. That's what made me post this in the first place. That and it stinks... :

Following that, I've been in touch with my local Loctite/Hysol rep and I have some industrial adhesive samples on the way.

Thanks guys...

< Message edited by Kelly W -- Mar 6 2003 8:39PM >

_____________________________

Kelly Williams, GTBA #1969

(in reply to Kelly W)
       Post #: 6

Poly fuse, bonding formers in place with epoxy? - 3/26/2003 10:28:32 AM   
Giant Scale



Posts: 856
Joined: 6/8/2002
From: Baltimore, MD, USA
Status: offline 		Be sure to thoroughly clean the fiberglass with acetone before applying the epoxy. Scuff sand the fiberglass and clean it again. This will remove any release agent,dirt..etc. I use west system epoxy with a slow hardner. Mix up a small amount of epoxy. Put epoxy on the edge of the former, this is the hot coat sort of like a primer. Position the former in the fuselage. To the remaining epoxy add some colloidal silica to form a thick mayonnaise consistency. With a gloved finger apply a fillet on both sides of the former all the way around. This will cure to form a very strong bond. Milled fiberglass will also work as a binding agent. I've also heard of guys using a bead of silicone to attach formers but I prefer the epoxy.

(in reply to Kelly W)
       Post #: 7

Page:   [1]
All Forums >> RC Airplanes >> Composites Fabrication And Repair >> Poly fuse, bonding formers in place with epoxy?
Page: [1]





Jump to:


Google 



Search | Marketplace | Event Calendar | Local Clubs | Magazine | Product Ratings | New Products | Discussion Forums

Photo Gallery | Member Video Posts | RCU Video Gallery | Instructor Search | Field|Track|Marina Search

Advertisers | Hobby Vendor Resources | Rate Manufacturers | Sign In/Sign Up

SITE MAP!   : :   FORUM RULES

© 2001 - 2007 24-7 RC, LLC, all rights reserved.

Charities we support that also need your help
Yorkie Rescue | Humane Society | ASPCA | Crohn's-Colitis America

Kaango.com Classifieds

0.547RCU5