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Sylvain · 03-11-2022, 06:39 PM

Quote:

Originally Posted by billchurch

Sylvain,

I see in your post where you are doing this.

https://www.airforums.com/forums/f20...ml#post2570814

And it has me intrigued. Any tips for getting the panels to run down that track? Id love to not do shell off if I don’t have to.

I do have a few tips actually.
- make sure the channel is clean and clear of everything but the bolts, which you will remove only when needed. Pay particular attention that there is no screws left. I had forgot a few, that made my life more difficult...
- Cut the board 1/8" to 1/4" shorter than the full width inside the channel to make it slide easier if the channel is not super straight. However, once you remove the shell-to-frame bolts you can have a bit of play as the shell is flexible.
- Route the edge of the board to a bit less than 1/2" inch thick if they are thicker than that, on a width that is if I recall 1.75"
- you could add wax in the channel to help. I only thought of that after...
- Make sure to plan were the board edges will end up, preferably on the frame crossmembers, before sliding them in. I had to cut one of the board in half to make two 2x7 foot boards personally to match my frame

- check everything twice. If you forgot one screw in the channel (as I did) the boards will be annoying to get in and you really don't want to take them out.

- The front and rear corners might need to be re-cut/adjusted with a dremel or oscilating saw once the board is in place

Sylvain · 03-11-2022, 06:41 PM

Quote:

Originally Posted by Minno

When we did we did our shell on floor replacement, we did it in 2 separate operations. We were able to remove bolts, remove old floor, cut new, and slide into place from the center of the trailer to the back, then same way to the front. We used full sheets of plywood, and clamped the frame to the shell where we weren't working with C-clamps. See our thread, "Little Girl Refurb" for more info and pictures. It's in the '70's section.

Kay

I pretty much did it the same way

Sylvain · 03-11-2022, 06:52 PM

Quote:

Originally Posted by billchurch

Okay, this is really shaping up to be my preferred method now.

The next challenge I was thinking about was how to fasten to the coosa.

I've seen people who covered the entire floor with epoxy and glass. I feel this is a little overkill. I do like the idea of doing a half-lap joint with some thickened epoxy (with csm or something else) where the coosa boards meet up (researching the ratios now for how wide the joints should be), to seal and bond the floor as a unit, but the whole floor seems like a bit much.

I've done some work with cored fiberglass before and the technique I've always used for fastening has been to drill an oversized hole, and if possible don't drill through the skin of the other side, basically we're talking about making a pocket. Then, mix up a slurry of thickened epoxy and fill this oversized hole. Then you can use just about any fastener you want. You could:

- tap and use machine screws
- stainless toggle bolts (did this a few times, worked great)
- self-tapping
- epoxy embed threaded inserts
- through bolt (as long as you can get to the other side).

The trick is the oversized hole should be large enough so that any force applied will be mostly to the thickened epoxy and not to the core, to save it from crushing. I don't know how much this

Another option would be to glass in the panels or hardware you want, providing a fillet at the corners and use fiberglass strips. I like the idea of things being removable though so I don't know if I'd go with this method.

I could also glass wood strips as battens to fasten to. So, I think I have a few options here and feeling pretty good about it.

Most of this is just me talking out loud but I'm definitely interested to hear any other suggestions or experiences for fastening to the coosa.

Excited to get started, but have to wait a couple of weeks for my timing to work out.

I used very flat flanged elevator bolts from McMaster of 2 different length depending on where they were used. I drilled through the board and through the frame with just the right diameter. Then with one of these large wood drill bit - can't recall the exact name- made a very shallow 0.1" flat recess in the board so that the head would not stick out. inserted the bolt in the bolt, step on it so the theeth flanges were biting into the coosa. Finally screwed the nut in on the other side with non removable high vibration loctite, in some locations two nuts because I had spares. The floor is not moving anywhere.
One thing that will make your life easier is to make sure to mark on the top of the coosa were the beams and crossmembers are as soon as you have a board in place. That makes it easier to know where to drill

Sylvain · 03-11-2022, 06:56 PM

I forgot to mention, I did not use half lap joint. The boards are just butt-to-butt. The biggest gap I ended up having was probably 0.1". I'll fill this up with body filler of sealant

Sylvain · 03-11-2022, 06:59 PM

The most complicated part in the entire process for me was to figure out how i was going to bolt the shell to the frame alone by myself once the floor in place as I can't be on both side at the same time.

I found a solution last week but have not done it yet

Aerowood · 03-11-2022, 07:36 PM

Sylvain, I just noticed that you are from Mojave. I spent several months there in 2010 as the project manager getting an Avionics upgrade on our C-130 at ASB Avionics.

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Sylvain · 03-11-2022, 07:43 PM

Quote:

Originally Posted by Aerowood

Sylvain, I just noticed that you are from Mojave. I spent several months there in 2010 as the project manager getting an Avionics upgrade on our C-130 at ASB Avionics.

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Nice! It is just down the road from me. Did you like the desert?

Aerowood · 03-11-2022, 08:40 PM

I was stationed at George AFB from 76 to 81. The desert has changed alot since then. No disrespect but I like Colorado better.

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Sylvain · 03-11-2022, 09:39 PM

Quote:

Originally Posted by Aerowood

I was stationed at George AFB from 76 to 81. The desert has changed alot since then. No disrespect but I like Colorado better.

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No worries. The desert is not meant for everybody. Actually in the people that I have met here more dislike it than like it. I was in the jungle of south-America for several years before moving here, so that is a big change but I love it.
Colorado seems really nice too. I have not been there yet.

dbj216 · 03-12-2022, 06:48 PM

When your Excella 500 is finished, you can hitch up and maybe travel to Colorado. A lot of people do. There are many "boondock" opportunities as well as campgrounds for the "base camp" and thin climb mountains all day, relax in your Airstream at night.

David

crazycuda · 06-30-2022, 12:26 PM

Quote:

Originally Posted by Sylvain

Although I have a 79 excella 500, I had to do exactly that. The original floor was 0.5 plywood so I routed the edges of the 0.75 coosa to make it fit in the channel. It is very easy to do, but dusty.

can you go into detail on what router bits and techniques did you use to router down the edge of the coosa. I am about to do similar myself in about 3 weeks