Spring prepapration advice

On Wed, 11 Mar 2015 08:52:51 -0700, unclhank wrote:

On Wednesday, March 11, 2015 at 11:23:27 AM UTC-4,
wrote:
The corner of my Ventus landing gear door got bent and needs to be
glued back to its former shape.
What epoxy should I use (I need a very small amount)
Need to clamp the piece while drying. What material to use so the clamp
doesn't stay glued to the door....?
Dan

For this you could use a slow curing epoxy from your local hobby shop. I
would not recommend 5 minute epoxy from your local hardware store.
Poly film placed over the repair before clamping will allow removal and
can help make the shape better.
Good luck UH

The heat-shrink film used to wrap CDs, cigarettes, etc makes a good epoxy
release film. IIRC clingfilm also works, but do test it before using it
in anger.

Epoxy: 24hour epoxy gives a tougher result than the 5 minute epoxies,
which tend to be brittle when cured. However if your gear door shows
signs of delamination, one of the laminating epoxies would be better
because its relatively thin and so can be worked in to saturate the
delaminated/fractured area. The better hobby stores will stock it in
fairly small amounts: look for Z-poxy or SP113.

When I bought my Libelle, the front of its gear goods were decidedly moth-
eaten so I repaired the damaged front edges and corners:
- made a thin (1/32") ply laminated former that matched the outside curve
(a good quality cardboard lamination would also do since you'll only
use it once)
- covered that with release film (see above).
- cleaned up the more ragged door edges with knife, Dremel and sandpaper,
removing paint etc within 1/2" of the cleaned-up edges.
- taped and clamped the former onto the door
- used laminating epoxy/glasscloth/fibreglass mat to build up an
oversized section to replace the missing door area.
- let it harden thoroughly.
- took off the former and put a layer of 35gsm/1 oz/ft twill weave glass
cloth on the outside so it overlapped the bared area of the door and a
similar layer of thicker classcloth on the inside. This vastly
strengthens the join while leaving a nice surface to paint on the
outside
- then cut off the excess so the repaired doors were a nice fit in the
fuselage.
- painted the doors and refitted them.

I realise your repair is different, but working laminating epoxy into the
bent/damaged area, clamping it to a former to keep it straight while it
cures and then putting 100gsm/3 oz/ft glass cloth on the inside of the
door to cover the repaired crease should make a good job. This requires
laminating epoxy. Ordinary tubes of 24 hour epoxy are far too thick and
gooey for anything to do with glass-cloth: try using it with classcloth
and you'll just end up with a mega-sticky, epoxy-soaked ball of glasscloth
stuck to your hands.

A good hobby store (either online or highstreet) should have laminating
epoxy and glass cloth in fairly small quantities or, if you have a nearby
sailplane repair shop, they may let you have a small amount of epoxy and
some glasscloth offcuts. If all fails, try:

Aerospace Composite Products http://www.acp-composites.com/
or
Composite Structures Technology http://www.cstsales.com/

Both are in California and are extremely knowledgeable about
composite structures, materials and how to repair them.


--
martin@ | Martin Gregorie
gregorie. | Essex, UK
org |