The top of the firewall now requires riveting to the left and right firewall panels but it has to have a bead of Proseal fuel tank sealant to stop gases entering the cabin. This stuff is probably one of the most obnoxious substances known to man and has a tendency to go everywhere apart from where you want it…what’s that on your nose etc, etc. I managed to get it in a syringe to produce the 1/16″ bead that Vans require.
Next up is setting five rivets to hold the panels in place. Some builders have back-riveted these but I couldn’t work out a good way to get this to lay flat so I built the ACME Rivet Assistant to hold the construction upright while I used the gun and bucking bar. So far so good and only a moderate amount of gloup as I had let the Proseal go tacky.
Centre section is dimpled and then Prosealed before being cleco’d to the left and right panel. Not quite so neat this time as it takes a little finagling to get it into place.
When you rivet the angles onto the firewall panels you have to be careful to follow the “dimple but do not rivet” instructions. On the plans it shows the top right rivet as being exempt from these instructions but if you read forward and see where the horizontal firewall angle goes, it is obvious that this rivet should be left out as well. Time to drill out two rivets…
With the help of a well fed riveting assistant the remaining rivets were set and all the nutplates added. The Nose Gear brackets are quite tight to access but they also take the Engine Mounts so it was essential that these were set well. They are reamed to .375 and Vans say to do this on a drill press. Quite how you get this structure on a drill press I’m not sure so I made some alignment blocks and carefully reamed them with a slow speed electric drill. It removed hardly material which is always a good sign.
Firewall complete. Getting a little space critical now until this all goes together.