Filling surface defect in fiberglass tube

Filling surface defect in fiberglass tube

Post by Brian Elfer » Fri, 18 Oct 2002 23:25:09



I dropped my all fiberglass airframe against a sharp edge the other day.  The paint was
damaged and the tube also got a chip out of it about 1/16" inch deep or so.  What can I
use to fill the damage before repainting?  The chip is only surface damage, not structural.

Brian Elfert

 
 
 

Filling surface defect in fiberglass tube

Post by Kevin Trojanowsk » Sat, 19 Oct 2002 00:22:30


Bondo body putty should work fine.

-Kevin

Quote:

> I dropped my all fiberglass airframe against a sharp edge the other day.  The paint was
> damaged and the tube also got a chip out of it about 1/16" inch deep or so.  What can I
> use to fill the damage before repainting?  The chip is only surface damage, not structural.

> Brian Elfert


 
 
 

Filling surface defect in fiberglass tube

Post by Dan Ledenica » Sat, 19 Oct 2002 01:15:12


On Thu, 17 Oct 2002 15:22:30 GMT, Kevin Trojanowski

Quote:

>Bondo body putty should work fine.

Kevin,

I have an entire body tube that was glassed with 9 oz. cloth.  Would
you use the same bondo to fill the heavy weave pattern?   I do not
want to add much more weight to the already heavy project.

Thanks, Dan

 
 
 

Filling surface defect in fiberglass tube

Post by Rob Bazine » Sat, 19 Oct 2002 01:19:05


Dan,

Try the stuff from Shadow Composites,
http://www.shadowaero.com/polyfiber.htm, called Super Fil.  I have used it,
works great and is VERY light.

-Rob


Quote:
> On Thu, 17 Oct 2002 15:22:30 GMT, Kevin Trojanowski

> >Bondo body putty should work fine.

> Kevin,

> I have an entire body tube that was glassed with 9 oz. cloth.  Would
> you use the same bondo to fill the heavy weave pattern?   I do not
> want to add much more weight to the already heavy project.

> Thanks, Dan

 
 
 

Filling surface defect in fiberglass tube

Post by Steve Wolf » Sat, 19 Oct 2002 02:09:17


Quote:
> I have an entire body tube that was glassed with 9 oz. cloth.  Would
> you use the same bondo to fill the heavy weave pattern?   I do not
> want to add much more weight to the already heavy project.

   I've had good luck by mixing up a batch of epoxy/microballoons about as
thick as I can get, and hand-rubbing it (with gloves!) into the tube, then
sanding.

steve

 
 
 

Filling surface defect in fiberglass tube

Post by Justin Helbi » Sat, 19 Oct 2002 01:51:51


I use "White filler" from the hobby stores.  It sand really well and takes
only about 20 min for it to dry.  They also make one called Green filler.
It comes in a really small tube for about $3.00.

Quote:
> I dropped my all fiberglass airframe against a sharp edge the other day.
The paint was
> damaged and the tube also got a chip out of it about 1/16" inch deep or
so.  What can I
> use to fill the damage before repainting?  The chip is only surface

damage, not structural.
Quote:

> Brian Elfert

 
 
 

Filling surface defect in fiberglass tube

Post by Brian Elfer » Sat, 19 Oct 2002 05:44:13


Quote:

>I have an entire body tube that was glassed with 9 oz. cloth.  Would
>you use the same bondo to fill the heavy weave pattern?   I do not
>want to add much more weight to the already heavy project.

What I do is sand the entire tube down as much as possible.  Then, I paint it with Kilz
primer.  I roll it on, or you buy it in spray cans.  After the Kilz, I wet sand the entire
tube.  I do this outside with a water sprayer to keep it wet.  The water keeps the sandpaper
from clogging up.

I build large rockets 7.5" diameter and up, so I can't afford enough spray paint, nor can I
afford auto paint.  I simply roll on Rustoleum oil based enamel.  A quart will do a 7.5"
diameter 12 foot tall rocket several times.

Someone suggested more epoxy on the tube, but that will certainly add weight.

Brian Elfert

 
 
 

Filling surface defect in fiberglass tube

Post by Kevin Trojanowsk » Sat, 19 Oct 2002 06:01:52


Quote:

> I have an entire body tube that was glassed with 9 oz. cloth.  Would
> you use the same bondo to fill the heavy weave pattern?   I do not
> want to add much more weight to the already heavy project.

I have a 7'x7.5" rocket I filled w/ auto body filler, and I didn't
notice any real weight gain from it -- all you're doing is filling the
little indentations.

I've found it easier to work with than the stuff from Shadow Composites.

-Kevin

 
 
 

Filling surface defect in fiberglass tube

Post by Robert DeHat » Sat, 19 Oct 2002 06:02:09


Or if you want to do it on the cheap.
Go to home depot and get a can of Rustoleum clean metal primer in the quart
cans and a couple brushes.
Brush on sevral heavy coats, maybe 3 or 4.
Take it OUTSIDE with your palm sander and 150 grit paper.
Sand till smooth.
The dust comes off like chalk so it makes a mess but it comes off easier
than anything else so dont worry about putting on too much.

Works for me.

RDH8
NAR L2


Quote:
> > I have an entire body tube that was glassed with 9 oz. cloth.  Would
> > you use the same bondo to fill the heavy weave pattern?   I do not
> > want to add much more weight to the already heavy project.

>    I've had good luck by mixing up a batch of epoxy/microballoons about as
> thick as I can get, and hand-rubbing it (with gloves!) into the tube, then
> sanding.

> steve