This is the first REAL part since the practice lay-ups. The foam I got from Aircraft Spruce was large enough to accommodate the entire seatback and I did not have to glue two pieces together. I cut the foam with a hot wire except the center hole for the maps.

It worked especially well for the 45^o angle cut. I placed the foam flat along the edge of my workbench. I then clamped an aluminum straight edge on top of the foam, parallel to the table edge and recessed .75”. Ran the hotwire along the entire length of the seat back – straddling along the table edge and the straight edge; a perfect 45^o cut can be made. I did make a directional error on one of the side-angled cuts but was easily repaired. Getting mad at myself was more damaging than the repair work itself. The lay-up part was straightforward. 

Lesson learned – I gave up finding the right time to knife trim. Instead I used the FEIN tool and learned how to make a tight cut along the edges. I also learned to use the plastic peel ply method as discussed in detail on John Slade’s Web site – Thanks John!

This is the first part that I had to glue multiple foam pieces together using the hinged method. Surprisingly, this method was quite easy and worked well. The biggest challenge was to get symmetrical & consistent rounding inside corners. These corners also have different radii. I tried wrapping sand paper around various diameter wood dowels without great success – because I do not have that consistent ‘touch’ from one corner to another – as a professional carpenter. I ended up with transitional bumps between the rounded corners to the straight edges. Its’ probably OK, functionally. However, if I have to look at the imperfection every time I get on the plane, I’ll hate myself for not doing something about it early on… As  a result, I had a set of angled templates with rounded corners made, resulting in a nicely rounded inside corner every time!

Making the vertical stiffeners was challenging. I followed the ‘plastic wrapped wood strip’ and BID tape recommendations by others. It was done, but the quality will definitely blow my Grand Championship Quality Award!

Lessons learned – BID tape and rounded corner templates.

One thing to look out for is the correct type of foam to use. The foam supplied by Aircraft Spruce was not marked. I had to go through the process of elimination to get the right foam. Adding to the confusion, their ‘tan’ color medium density PVC foam was .274” thick instead of .25” per plan. I had to get assurances from several experienced builders before cutting the foam.

Due to the slight thickness of the foam and somewhat aggressive squeezing of the BID layers for the hard points, they ended up too thin. With some careful measuring and estimating, I ended up with 27 layers of BID cloth instead of the 22 layers per plan. I did get a nice flush between the hard points and the foam. You can see the peel ply that was partially trimmed and pulled back as well as the plastic peel ply.  

You're probably wondering what in the world are those round inserts – instead of the 1” square inserts per plan. Based on the Wayne Hicks’ and others web site, it was suggested that a larger insert (~1.25" sides square) might be worthwhile. Therefore, instead of the 1”x1” square inserts, I had 1.75” diameter (diagonal length of a 1.25" square) aluminum discs made in their place. Besides, it was easier to cut a round hole in the firewall (using a hole saw) for a nice clean fit.

As I pushed the MS24694-S54 screws into the blind holes, they felt quite snug. Therefore I did not do anything more than per plan. I ground a flat on each screw head, countersunk the holes and installed with flox. Waited for the flox to cure and glassed the forward sides.