I figured I'd start a thread in the packrafting section to document the creation of my inflatable PFD since I'm super stoked about it.
The project started off as a hybrid air/foam PFD, but I've now shifted directions and I'm making purely an air PFD. I decided filling the air chambers about 1/3 to 1/2 full of foam would significantly increase the bulk and weight, while still sucking at being a PFD since it would be below the minimum amount of float I really need. Accordingly, this PFD is now an ultralight inflatable PFD for moderate wilderness use, and I'll use a more robust foam PFD if I ever start creek boating locally.
All materials to date have been ordered from QuestOutfitters.com
Stage 1 - Making the Vest
Using 2.2oz 70D nylon, I set about making a basic vest. I traced the outline (minus the sleeves) of a shirt that fits well onto my fabric. Then I cut that out and make a duplicate so I had two halves. I then sewed them together using flat felled seams.
Then I made the 'front' more of a front by adding a 'V' to the neck line and I cut it open down the front. I then enlarged the sleeve holes, mostly towards the front and bottom (as you can see in the first pic), so that there is lots of room to paddle without interference. Once I was happy with everything, I sewed on the edging from Quest. Unfortunately I didn't order quite enough (3 yards) so I'll have to finish the edging later.
Stage 2 - The Back Chamber
With the vest made, the next order of business was to create the 3 air chambers (one upper back, two on chest) needed to float. I decided about 22 lbs of float (10 back, 12 chest) would be a decent amount, since I don't plan to run crazy white water with this.
I sat in my pack raft and figured out where I could position the air chamber that wouldn't interfere with my use of the back rest. I did think about eliminating the raft backrest and incorporating an air chamber into the vest instead, but I didn't want the floatation getting too low down my body because I want to make sure I float head up.
I deciding on a back chamber of 12" (wide), 9" (tall) and 2.5" thick. This gives me a total of 270 cubic inches and 9.7 lbs of float. I suspect in reality because the chamber will bulge a bit away from a perfect rectangle, I'll get a bit more float than this.
To make the chamber, I used 70D heat sealable nylon (from Quest). I didn't want to bond to equal halves together like is normally done to create sleeping pads and pillows, because I wanted a non-symetrical shape that would sit nicely against my back. This is hard to explain, so I'll let the photos do the talking:
Flat side, which will get sewn to the vest around the 3/4" bonded perimeter:
I'm super stoked about this air chamber. I still need to add the valve. It's going where my fingers are in the first picture. By putting it in the corner seam, I leave the perimeter seam intact so I can sew it to the vest all the way around.
As a side bonus, this is going to make an amazing pillow.
I haven't totally determined how I'm going to sew it to the vest yet, but it shouldn't be too hard. I might cut a hole and reinforce the edge before sewing it to the chamber, or I might just sew it on.
The work continues...