(Page 22-03) The belly of the beast......                             

The assembly of the stainless steel Firewall Bottom and Firewall Shelf held no surprises.  It was my first exposure to the much discussed and dreaded ProSeal (fuel tank sealant).  I ordered the 1 oz container from the mothership and this proved way more than enough.  Instructions are minimal, so I mixed the two parts as if it were epoxy, smeared it on the upper firewall flange, did the prescribed riveting, and all was well.  I had no idea whether the working life of the ProSeal once mixed was five minutes or five hours, but it all worked.  If I had it to do again, however, I'd do step 8 before step 3.  The F-1201L bracket must be held exactly in place with one hand (preferably with a block of wood so fingers don't get drilled) while match drilling from the opposite side of the firewall.  It would be easier without the shelf installed.

 My first attempt at making said bracket from the 3/4 by 3/4 angle resulted in a piece I scrapped for minor deviations in dimensions.  After remaking and installing it, I realized the first one would have been fine since all holes are match drilled through the firewall and tunnel rib.  No dimension for the bracket is critical.  The picture shows my tight-fit, right-angle drill attachment, which was needed for drilling into the tunnel rib.

To attach the Forward Lower Fuse Assembly to the Lower Fuse Assembly and Bottom Skin, I turned the fuselage on its side (shown).  This allowed me to hold and cleco the forward assembly without assistance from the Spousal Unit.

Next up are the dreaded longerons, which involve among other things spreading a 3/4 x 3/4 angle to 95.4 degrees.  Point four degrees?  Really?

(page 22-02 again) My 433rd favorite thing.....                    

...drilling out rivets.  Continuing the curse of this section, I fabricated the Firewall Spacers for step 12, did the match drilling for the Cowl Attach Plates, and proceeded to rivet these to the Lower Fuselage Assembly.  This involved squeezing some longish 1/8th inch rivets, which I have come to dread because it exacerbates a rotator cuff injury I've developed, probably from squeezing 1/8th inch rivets.  Turns out that the inboard two rivets are a problem.  The LP4-3 shop heads of the rivets which attach the tunnel ribs to the lower firewall make it impossible to square up the squeezer with the rivet.  I put the manufactured heads on the aft side of the firewall since I'm still not sure what will be visible from the cockpit.  After two failed attempts at squeezing two of the AN470AD4-5 rivets (followed by drilling the buggers out) I surrendered and drilled out the aforementioned LP4-3s, allowing a proper alignment of the Main Squeeze.  The squeezer must be absolutely 90 degrees to the surface of the aluminum.

The moral of this story is this:  When riveting the Tunnel Ribs to the Bottom Skin in step 6, don't rivet them to the lower firewall until after step 12.  This will completely avoid what I went through tonight.  The picture shows which rivets (two on each side) to hold off on until after step 12.

(page 22-02) One omission and one mistake....         

The omission was Van's (confirmed by them). Step 2, sentence 3 should read as follows: Machine countersink the uppermost hole in the F-1288 Cooler Stiffener and all rivet attach holes.  The mistake was all mine and had nothing to do with the omission.  After carefully doing the cutting and deburring, I countersank the hole on the wrong side.  Only cost a few bucks to order but it set the tone for much confusion to follow.  In step 3, everything after the words Tunnel Ribs should be deleted.  I wasted quite a bit of time trying to figure out how the instructions, saying to rivet nutplates to the firewall bottom, could possible make sense.  Turns out they couldn't.
Step 9 has the instructions for those nutplates in the proper sequence.  Overall, I've been quite pleased so far with the entire kit, including the build manual.  There are a few places, however, where I wish they'd let me rewrite it.  I'd do it free! 

The firewall is stainless steel and everything that I'm attaching to it is aluminum, so I was a bit concerned about dissimilar metal corrosion.  I ended up priming the entire firewall (scuff with maroon ScotchBrite, clean with acetone, spray with NAPA 7220) as well as the faces of the aluminum pieces which attach to it.  Throughout the build, I've primed all mating surfaces with self-etching primer from Lowe's, which costs about one-third what the NAPA stuff costs.  The EAA instructional videos push the NAPA primer (which is made by Martin Senor) as do the people on the forums.  I did some informal scratch tests and couldn't tell any difference.  I used the "good" stuff here since it's the foot well and parts of it could presumably be visible around carpeting.  I'm not sure what goes in there, actually.