A backing board was made from some extra MDF that I had laying around
the shop. It was made about 1/4" smaller than the firewall formblock.
The stainless steel was properly positioned between the formblock and
backing board and the whole sandwich was clamped using several "C" clamps
as shown here:
The dead blow mallet was then used to form the flange much like was done when forming the wing ribs.
Here is the completed firewall after it was back-drilled and bolted to the
The little splotches are actually my fingerprints all over the place.
And finally, here is the firewall with the engine and mount bolted in
As a double check, I clamped the nose bowl in place and ran the strings as before. Everything fit perfectly and the strings make a nice smooth transition from nose bowl to instrument panel and door flanges.
Total time: 16 hours