AT-6 Texan firewall re-build- plywood plies have separated but still in 1 piece

[Frank v B]

The firewall on this plane was flexing after a pancake landing on a very windy day a week ago.  There were no cracks but the plywood layers started to flex and separate.  The perimeter was still attached properly to the fuse.

steps
1- remove the motor and cowl to expose the firewall.  Put masking tape around the fuselage side.
2- apply vaseline inside the motor mount nuts so the epoxy will not stick. I used a toothpick. Photo 68
3- cut fibreglass a little larger than the size of the fuselage/firewall
4- apply 5 minute epoxy to the raw plywood firewall.  I used a brush.
5- drop the fibreglass cloth onto the epoxy and press down. Photo 69
6- add epoxy to the surface of the cloth to properly soak it. Photo 70.  In hindsight I should have thinned it with about 15% denatured alcohol.  Will do so next crash repair.
7- when the epoxy had started to set up but was still flexible (approx 10 minutes) I used a pair of scissors to cut the cloth to the shape of the fuse.  Also used an X-Acto knife to cut out the lightning/vent holes. Photo 72.
Note: I did not cut out two of the lightning holes because they are under the nose weights screwed onto the firewall.  They block the vents and preferred to keep it strong.  One of the weights is shown in the picture.

Letting it cure overnight before re-assembling the motor/cowl/esc.

Frank



Total time of the repair was 20 minutes.