Preferred Attachment for Floorboards

[bubb2]

I had the pleasure of removing the original plywood floorboards from a low time 1953 PA18A and noted Piper had assembled the floorboard/pedal sandwich with drilled bolts, castellated nuts with cotter keys. Not sure what the reasoning was. I also note the PA18 parts book does not list any attachment hardware for this assembly.

I then read some of the methods others mention on this sight on attachment of carbon fiber floorboards with some folks going a bit overboard (maybe?) to ensure not crushing the floorboard causing latter loosening.

With the substantial weight savings with carbon fiber and its use becoming more and more common any attachment method proving to be better than others?

 

[stewartb]

What in your opinion is “going overboard.”

My floor is foam core carbon sandwich, approx 1/4” thick. Attachments are to nut plates on welded tabs with truss head screws. Where fasteners require torque, like at AP servos, the boards are over-bored and bushed. Nothing is attached to just the boards themselves.

 

[bubb2]

What in your opinion is “going overboard.”

Earlier posts like these below MAY indicate some people go a bit overboard. Nothing wrong with overbuilt, I guess.

"I put carbon concepts floorboards in almost ten years ago. Drilled holes just like piper did in the rotted wood that I replaced. Close to 1000 hrs with no bushings. Don’t over think things."

"On floorboard attach locations I just used a a large head #10 screw snug with a Phillips screwdriver. I’d guess maybe 10”/lbs. Neither the floorboards or screws want to move. No damage to the Carbon fiber. Year 13 now."

 

[fishhook]

I bush the holes on a boards that are foam core or honeycombed. I go overboard. Lots of friends do not bush the holes and they all have had good luck. Nylocks and countersunk screws with countersunk washers makes a clean install wood, carbon, or whatever. Monadnock clips are nice because then you can pull the boards up easier after cover except messing with the pedals. The absolute bulletproof way is a bushing just under the thickness of the board so you barely squeeze the board when tightened down for foam core board. Or just a couple of drops of thin epoxy after drilling the holes firms the foam up a lot. Or nothing at all and just dont crank the hardware down and you will have no issues.

 

[Bill Rusk]

I did not bush the holes, or reinforce in any way. I did not finish out the edges either. 1800 hours, most of that on floats so constantly wet, and they look pretty much the same as when installed. The holes are not crushed or wallowed out. The length of time to finish the build is directionally proportional to the completion rate, but each builder must satisfy his (or her) conscience, and go home at night comfortable that he met his personal standard of craftsmanship.

Bill

 

[Sikorsky]

I drilled a small hole where I wanted the holes, picked the foam out with a metal dental pick or similar, taped one side, and injected epoxy glue. Re-drill hole through the epoxy. Bolt goes through to a nut plate. Pleased with this method and probably would do the same again. No crushing, and stronger than bushings unless you glue them in. Opinion.

Zach