How much Proseal

[cdeerinck]

I need to install 2 locking gas cap sleeves in the wings.

http://www.aircraftspruce.com/catalo...ickkey=3019014

Can anyone tell me if 1oz of Proseal will be enough, or should I get 3.5 ounces?

[tgmillso]

For most flanges in the tanks, the rule of thumb equation is one gram of proseal for every linear inch of flange interface. Measure the circumference of your tank flanges and round up from there. The tank flanges are probably a little wider than the normal 5/8" rib flange, so you may need to add a margin accordingly.
Good luck.
Tom.

[rdamazio]

I did mine recently as well - while I can't tell you the exact quantity I used, it was very likely less than 1oz. I used a 3.5oz tube to do all of: both tank senders, fuel return brackets on the tanks, 6 tank plugs (2 fuel pickups, 2 fuel return, 2 drain), tailcone NACA vents, tailcone static ports, 2 fuel caps. By the time I was done I still had about 30-40% of that tube left.

[rdamazio]

(a detail to keep in mind is that you only care to apply sealant to the top part of the new cap flange, which will attach (through the sealant) to the already-installed flange, and that old flange is not very deep)

[Carl Froehlich]

Rodrigo,

Recommend you put a ground wire (ring terminal) under one of your fuel sender screws and then proseal on top of that.

Considering all the proseal, the fuel sender may or may not have a good ground. Simple to do now and avoids problems later.

Carl

[rdamazio]

Originally Posted by Carl Froehlich

Rodrigo,

Recommend you put a ground wire (ring terminal) under one of your fuel sender screws and then proseal on top of that.

Considering all the proseal, the fuel sender may or may not have a good ground. Simple to do now and avoids problems later.

Carl

Thanks for the suggestion. I did test the conductivity between the surface of the sender plate and the skin, and it's conducting well on both tanks (I also measured the resistance from the skin to the sender terminal and it's giving me 235 ohms at one of the extreme positions, which is expected) - do you see any reason to add the ring terminal anyway?

When I installed the senders, I applied sealant on the inside of the sender plates (including some on the inside of the holes, but not the outside surface where the screws would sit), then fastened the screws, and only then applied sealant on top/around them to ensure they wouldn't leak, so there's good contact between the screws and the sender. I'm thinking that any resistance offset from the ground path through the screws and structure will be corrected by the calibration process.

[Carl Froehlich]

Originally Posted by rdamazio

Thanks for the suggestion. I did test the conductivity between the surface of the sender plate and the skin, and it's conducting well on both tanks (I also measured the resistance from the skin to the sender terminal and it's giving me 235 ohms at one of the extreme positions, which is expected) - do you see any reason to add the ring terminal anyway?

When I installed the senders, I applied sealant on the inside of the sender plates (including some on the inside of the holes, but not the outside surface where the screws would sit), then fastened the screws, and only then applied sealant on top/around them to ensure they wouldn't leak, so there's good contact between the screws and the sender. I'm thinking that any resistance offset from the ground path through the screws and structure will be corrected by the calibration process.

Looks like what you did worked. Remember to recheck once the wings are on to make sure the ground is good all the way to whatever you are using for your common panel ground.

I find it easy to just avoid the issue and add a ground wire.

Carl

[rdamazio]

Originally Posted by Carl Froehlich

Looks like what you did worked. Remember to recheck once the wings are on to make sure the ground is good all the way to whatever you are using for your common panel ground.

I find it easy to just avoid the issue and add a ground wire.

Carl

Thanks, will do.