Taping the bulkheads

So now that the fuselage sides were bonded (with flox) to the bulkheads, it was time to apply the BID tape to the bulkhead / fuselage mating edges. Basically, this acts like a fiberglass "L" extrusion that supports the bulkhead onto the fuselage sides. The plans say to do this while the flox is still wet; but since I was limited on time, I had to do this step after everything had cured.

Step 1 was to cut the BID tape strips. At first, I thought BID tape was something you bought 'off-the-shelf'. But it turns out, BID tape is simply strips of BID (about 3" wide) cut to the length you need. They have a 45 degree orientation.

The plans aren't clear on whether or not the firewall receives a few strips of tape; I figured it couldn't hurt so I cut some for the firewall as well.


After cutting the strips, I prepped my bench to prepreg the strips. I started by laying a strip of cling wrap onto my table top...

I then placed a strip of BID tape and poured resin onto it... squeegeed it out (wetted it out), applied another layer of tape and wetted it out...

 I then cut the strip to the proper length to give me a nice clean cut. Notice how I cut the cling wrap WITH the fiberglass.


I then prepped the bulkhead/fuselage mating surface by sanding it smooth and brushed on some resin to the surface.

 I then applied a bead of flox using the "bakers icing on the cake" trick.
 I then lifted the prepregged fiberglass 'tape' off my bench... and applied it onto the mating surface.

I applied it with the cling wrap on the outside, positioned it in place, and then peeled the cling wrap off like applying a band-aid. I then used a brush to tuck the fiberglass into the corner and removed any air bubbles.
 I then peel plied the edges.

This process was then repeated MANY more times... for the front seat (forward, aft, left and right sides), the rear seat (forward, aft, left and right sides), the instrument panel (forward, aft, left and right sides)... you get the picture.

Here is the rear seat...

Showing the cling wrap prepregged fiberglass tape being applied like a band-aid...

Peeling the cling wrap off. Notice how I let the tape extend past onto the through holes. This is easily trimmed using the dremel tool after its cured.

Getting rid of air bubbles...

And vuala! BID tape applied!

Here is the F22 bulkhead. The plans only has you apply tape to the area outlined in red for now. It later gets reinforced in later chapters. Here, I sanded the area dull, brushed on resin to the mating surfaces and applied a bead of flox to the corner.


I then applied the prepregged tape and peel plied the edges for a smooth transition.


Here is an example of taping the instrument panel; same procedure here... sanded the mating surface dull, brushed on resin to the mating surfaces and applied a bead of flox...


and then applied the prepregged BID tape.


Same thing with the front seat edges...



After all the tapes cured overnight, I then trimmed all the through-holes (using the dremel tool) and sanded everything smooth and flush!


I turned the fuselage over on its side to make it easier to sand all the edges smooth!


And there you have it! All the bulkheads 'taped' to the fuselage sides!


Next up... the F28 bulkhead and doublers!

8 comments:

Capt Meatballs said...

Looks great Ary. I like the look of the epoxy you use, it's nearly invisible.

Ciao, Marco.

Ary Glantz said...

Thanks Marco! I can't wait to paint it though; since it's nearly invisible, you can see ALL the lines and scribbles I made using the sharpie marker. I guess I'll just have to contain my OCD until it's time to paint! The good part however is that it lets you see any air bubbles or dry spots immediately - so it's easy to fix before it cures!

-Ary

Crockett Motor Works (CMW) said...

Awesome. Very well done. What type of epoxy did you use before switching to the Areoepoxy.

Ary Glantz said...

Thanks Bart! This was all done with Aeropoxy. I only switched to EZ-Poxy later when I glassed the fuselage exterior for Chapter 7. This is because Aeropoxy is NOT fuel resistant and part of the exterior fuselage actually becomes part of the inner fuel tank.

That said, I'm not so sure EZ-Poxy is 100% fuel resistant, but it is more fuel resistant than other epoxies. When I contacted Endurance Tech (makers of EZ-Poxy) questioning if EZ-Poxy is in fact fuel resistant, they sent me a bunch of charts and graphs showing how fuel only eats the composite at an extremely slow rate (something like less than 0.1% weight change in a period of 28 days). This still hasn't put my mind at rest; after all, just because it's extremely slow, doesn't mean it's ok. I'll have to do more homework on this later - if all else fails, I'll have to apply a special sealant to all surfaces in the fuel tanks.

Here is a link that explains the situation pretty well:

http://forum.woodenboat.com/showthread.php?5628-Epoxy-suitable-for-fuel-tanks

Louis Vales said...

Ary, I must say, you did a great job on these videos, watching them at the current speed drives me dizzy. Is there any way I can purchase a copy of your vedios so I can watch them at my speed...

Ary Glantz said...

Thanks Louis. Unfortunately, I don't have real-time videos of my build - I have a DSLR camera that takes a high-res picture once every minute. I then compile these pictures into time-lapse videos you see posted on my site. If you have any questions I can help answer, email me at thelongezbuild (at) gmail (dot) com.

Anonymous said...

Hi Ary,
this question of fuel resistancy did not leave my mind as I, too, will experience this problem.

I found this company offering bladder-type safety fueltanks: http://www.merin.it/en/index.php

These things are not cheap, but often cheap becomes very expensive, so I'm giving it some serious thougt.

Ary Glantz said...

Thanks for the link! That's not a bad idea! I will look into it once I get to building the strakes.