Bulkhead weight loss

For whatever reason, I decided to log the weight loss of the starboard float forward bulkhead from unpacking to final trim. No real idea why - maybe just because I "could".

:)

Results below...

The final bulkhead to be built for this float is the center one which incorporates additional fabric layers for the chainplate and also a water tight access panel. Since I'd like to avoid fitting that access panel later on within the confines of the float I am going to attempt to get it done ahead of time before installing the bulkhead. To that end, I just got off the phone with Armstrong Nautical to place an order for a couple 10"x20" (254mm x 508mm) rectangle deck plates. I probably should have ordered some 8" (203mm) round ones as well for the tops of the floats, but those can wait for a while.

Once they arrive, I will work on figuring out the best way to get them installed.

At the moment, I'm thinking about a 1/2" (12mm) ring of Hi-Density foam installed around the perimeter of the opening where the gasket will seat and some Hi-Density epoxy at the four pinch points. I'm also thinking about recessing the foam so the deck plate sits flush with the surface of the bulkhead. That isn't really necessary, but I think it will be a good idea to work out the flush mount details before moving on to the more visible elements of the build (deck hardware, hatches & etc.)

I can't believe how useful the laser level is for this project.
The first thing I did was clean up the bulkhead location and mark the AFT edge with some tape straight edges.

Removing the Starboard Float forward bulkhead from the vacuum film.
This was a vacuum bagged piece, but the results are really quite nice.

Initial weigh in
This is straight out of the bag.
Peel ply removed but excess flange material still in place.

Excess flanges cut off (Rough cut)

Final trim completed

Marked and cut into halves with a small center strip removed as excess material

Beam position cut-out

Final weigh-in before gluing into float

A total loss of 701grams!
(That's 1.54lbs for some of us)

And glued in place with a narrow bead of thickened epoxy putty
(Total time invested was almost five hours)

SB Float forward Bulkhead - Bagged

I'm not quite sure what the problem is, but after three failed attempts at infusing the second bulkhead I gave up and settled for vacuum bagging. I say I don't know what the problem is, but I really suspect that the shop & resin temp is just too low for a good flow.

The first two times I attempted this resulted in a vacuum leak that I simply could not find. (I suspec t the greenflow media punctured the bag) The third time I had a good seal (used an additional layer of bagging film over the greenflow media to ensure it did not puncture the bag) but the resin flow stalled after 1/3 of the bulkhead was completed.  That was pretty frustrating, so I shut off the pump and removed the bag and wetted out fabric pieces before scraping the foam clean and setting things up for vacuum bagging. I'm also nearly out of infusion resin, so the vacuum bagging solution allowed me to use my supply of laminating resin instead. The end result is really VERY good and I was even able to reuse the vacuum bag film and even the sealant tape for the second side.

The second bulkhead is now completed on both sides and has been curing under vacuum for the last 36 hours. I'll pull it off the table tonight so I can work on setting up the last bulkhead for bagging.

In the meantime, I was able to spend some time working on trimming out the aft bulkhead for a good fit. It took four hours to get it where I wanted and then cut in half for gluing into one side. At the moment there is no fillet as I only wanted to glue the bulkhead in place with no excess glue squeezing out of the joint. Once all three bulkhead halves are glued in place and checked again I will glue in the HD pads and then work on the fillets.


After that's done I'll finally be able to start removing the screws holding the SB OUTER float half in place so we can roll it over and slide it into position. Once that's lined up over the SB INNER half, I'll be able to verify bulkhead location matching and get those glued in place before gluing the halves together.

Lots of work ahead, but things seem to be falling into place.

Marking float location and also a second set of (outer) marks for peel ply removal

First attempt (failed due to vacuum leak) at bulkhead infusion

In the end I settled for vacuum bagging

Accurate placement of AFT bulkhead for marking and trimming

Good fit - slightly undercut to allow for epoxy gap filling

Marking for initial beam location cutout

Cut out and ready for final cleanup

Aft bulkhead comes in at 1035grams (2.2lbs)

Finally located and glued into place with a thickened epoxy bead

Carbon Bulkhead - One of Three

The first bulkhead (Starboard Float Aft) is completed and cleaned up a bit.
Weight at this step is just over 1200grams, but I still need to cut out a large section in the middle to accommodate the beam ends.

The second bulkhead (Starboard Float Forward) is wrapped and ready for infusion.
Hoping to get to that this weekend and then it'll be on to the middle (Chainplate) bulkhead.