Glassing and bonding the floor

After the floor contours were all smooth and perfect (or close to any how), it was time to build a jig that would hold it in place while glassing.

I started off by placing the floor onto the fuselage (aligned with the side markings), laid a few 2x1's and then used two 2x4s along the length.

 I then placed a heavy box over the 2x4's and began to shim everything in place. Notice how I screwed on a 4x1 on both the front and back end (onto the 2x4's) - this was to give the entire jig structure greater stiffness and not have it come apart when moving it off and on the workbench.

To hold the 2x1's, 2x4's and shims with the foam, the plans calls to use Bondo. It's pretty simple to use. Just follow the instructions on the can. Make sure to only mix a little (golf ball size) at a time. Bondo dries quick - you only get about a 5-10 minute window before it starts to get clumpy.

Here I am using small dabs of bondo to hold everything in place. I made sure to dab on a little onto every mating surface - the foam to the 2x1 - the 2x1 to the shim - the shim to the 2x4 - etc.

After 30 minutes or so, the dabs were completely dry. I then took it out of the fuselage and onto my temporary work table.

 I then cut the fiberglass cloth and test fitted it. The plans calls for 2 plies of BID at 45 degree. A third ply is added in the aft section where the passenger sits - this is to add more support where the passenger stands on when getting in and out of the aircraft.

I labeled each cloth panel with an axis system and numbered it. This was later used to help orient the cloth just prior to glassing.


At first, I was going to leave the wheel well hole cutout as is (to prevent the cloth from sagging while glassing). But then I thought about how difficult it would be to cut it post-cure, especially since the edge of it butts up against the instrument panel. So I decided to stick with what the plans say and proceeded to cut.

Ready for glass!

 I started out by mixing up some dry micro and filling in any voids.

 After all voids were filled, I slurried the entire floor and started laying cloth. Notice how I laid the 'third ply' first (the ply that goes on the aft section) so that it would hide the transition better.

After a lot of epoxy mixing and wetting out cloth...

 I decided to wait until the next day to bond the floor onto the fuselage (after 5 hours of glassing, I did not want to screw that up) - so I peel plied all the edges..

After a full cure, it was time to trim the edges. I opted to use my 'let cure, trim with the vibrating hand saw, then router it flush' method rather than knife trimming. This might be a bit more work, but I do this for a few reasons: 1) After I am done glassing, I normally head inside and call it a night - I don't have time to sit around for 2 hours to then go back and knife trim 2) the router gives a very clean, perfectly flush cut up against the foam 3) knife trimming disrupts the layup - you then have to go back and make sure everything it pressed down.

Any who, back to trimming the edges...

 Here I am trimming the edges with the vibrating multi-tool. I trim as close as I can without damaging the foam (about 1/8" or so).

 This leaves a messy, wavy trim line.

I then use the router to finish the job.

 Notice how perfect of a trim this leaves...

 Here is the front end. It was very important to have this line straight so that it would fit perfectly flush with the F22 bulkhead.

Since I waited to bond the fuselage after the glass had cured, I had no choice but to trim the aft end flush and make an extension to bond with the outside of the rear seat.

 I took out some scrap plies of 45 degree BID and began to prepreg...

I then installed it onto the rear seat section. Notice how I used a few pieces of foam to temporarily hold the trailing edge. Also, notice the use of peel ply to give a smooth transition onto the seat.

 It was now time to mix up some flox and apply it onto the fuselage...

Moment of truth! With Elle's help, we positioned the floor onto the fuselage. Using all the heavy boxes I could find, I placed them on top to weigh everything down into place.

And there you have it! The fuselage now has a floor!

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