First, Build a Shed

[Cherrybark]

It will be great to finish this stage but there is a long list making up the last 10% including little projects, like the lenses for the wing tip lights, that are going to take a lot of time. Sometime in Spring if I keep chugging along.

Along with the boot cowl, I wanted there firewall end plates to be removable for access to the brake cylinders and tubing. Should a sealant be used here or does that create too much of a permanent bond?

[PapuaPilot]

I would say that is up to you to decide. Sealant would be nice and it would be very rare that you would need to open the end plates. The sealant could be cut using a utility knife or by pulling some safety wire through it.

What sealant are you using? I used the 3M Fire Barrier 2000+ on my firewall seams. I put a bead on all of them before riveting them together.

[David47]

Why not a form in place seal, with a release agent on one side ....

[Cherrybark]

Sealing a firewall is new to me and I'm not familiar with any products or methods. Point taken that there won't be that many occasions that access is needed to the back of the rudder pedals.

The boot cowl has only been temporarily mounted to mark the trim line. Seems like there should be a seal where the cowl mates against the firewall but I don't remember seeing anything in the manual. Not sure how to have it sealed yet removable. I'll do a little searching on the forum.

The 3M Fire Barrier 2000+ stays flexible and is single component. Has the advantage of being readily available.

David, can you give me a product suggestion or explain more on how to form a gasket with a release agent?

[efwd]

Hey Carl, John M told me once that I could apply wax to the under side of the cowls where they touch the firewall. Use a sealer compound of your liking. When you pull it off in the future the waxed surface will release the sealant from the fiberglass easily. Of course then you have to spend a bit of time getting the sealer off the firewall. That is certainly nothing new. I have spent many of hours doing just that on helicopter engine decks.

[Cherrybark]

Ah, now I understand David's "release agent". Thanks for the tip Eddie.

[David47]

Yes, sorry Carl, I should have explained. Eddie has essentially described the principle, which is that you inhibit one surface from allowing adhesion. So if you used, for instance, a polysulphide sealant (PR sealant) or RTV as the seal material, you could apply wax, grease, teflon etc (maybe even LPS-1) - the release agent - on one surface, apply the PR, apply a bit of pressure so that you retain sealant thickness, and then let it cure. You should then be able to seperate the two and have a decent seal/gasket attached to one surface. But I'd check out the effectiveness of any release agent on a trial fit before trying the real thing. That's the way I'm doing it when I get to that stage. Hope this helps.

[Cherrybark]

Ta-da!

My 912iS was purchased from the factory and it arrived with the mounting ring and exhaust system installed. The muffler can was in the way of the lower two engine mount bolts and had to be removed. Made several attempts to remove the exhaust springs with various pliers but really didn't want to scratch them up or bend them. Hit on the idea of tying a small loop of parachute chord on the hook of the spring and tying another larger loop near the floor. Putting my foot in the lower loop and stepping down gave plenty of pull to stretch the spring and my hands were free to gently slip the spring out of the mounting tab. You will be tying eight small loops and it's a great time to learn the always useful bowline knot. The engine was hanging from a hoist.

The factory installed exhaust system was assembled "dry". The following forum thread discusses using anti-seize compound where the down pipes join the muffler. Also suggests running a bead of high temp silicon along the springs to dampen vibration. Ordered small tubes of nickel based anti-seize and a high temp silicon. The springs were already neatly safety wired.

http://www.teamkitfox.com/Forums/sho...exhaust+spring

Took a large pair of channel locks to compress the motor mounts sufficiently to start the crown nut. Was very happy when the last one was threaded on and everything torqued and pinned.

[efwd]

"Ta-da!"
Bravo! Bravo!. Looks great Carl.

[rv9ralph]

Carl,
A suggestion for the exhaust slip joint springs. Go the the local auto parts store and look at the brake spring tools. They are designed to grip the inside of the curve on the ends so you can stretch the spring and guide the end into the holes (or in reverse remove them).

Ralph