In practice, the inflated bags filled up virtually all the cabin space,
making entering the cabin impossible.
Flotation bag providing 550 lb. of positive flotation.
Bag dimensions before inflation = 30" wide x 70" long.
Bag dimensions after inflation = 19" diameter x 53" long.
Tools and materials, including acetone, gloves, HH-66 vinyl cement, scissors,
pen, bulkhead fitting, framing square, straight edge, painters tape, wall paper roller,
wax paper and rag
Use framing square to square off both ends of fabric. Most vinyl coated
polyester fabric comes in about 60" width. If using full fabric width, finished bag
will be about 17" shorter than cut length.
After marking fabric, cut to line.
From one corner, mark for bulkhead fitting. Shown is 8" in from each edge,
but locate to suit.
Use nut from bulkhead fitting to mark hole
Cut into middle of hole mark. Note the fabric pattern in this photo.
We put this on the inside of the bag.
Then cut around perimeter of hole mark
Using straight edge, draw mark 1" in from both ends
Put painters tape down each mark
Do same on both long edges as shown here
Mark mid-point of each end. Our fabric was 61" wide, so mark is at 30-1/2".
Also mark 1/2" either side of mid-point mark (these marks not shown)
Also mark mid-point of one long side. In this case, our bag was 70" long,
so mid-point was at 35". Fold over opposite long side and mark even with
Fold one long side over so it is centered over mid-point marks on each end.
Then, tape securely to table or floor so as to stretch this edge slightly.
It's important that this edge be flat, without any wrinkles or puckers.
Wearing gloves, clean edge with acetone.
Apply HH-66 cement to long edge
Then apply cement to other long edge
After cement is no longer tacky (2-5 minutes), place wax paper over cemented
edge as shown
Fold other long edge over so cemented edges are directly over other and
marks are lined up.
Carefully pull wax paper lengthwise out from between cemented edges.
Cemented edges will adhere instantly upon contact, so do this slowly and
carefully, checking frequently to be sure no puckering occurs and edges
are aligned with each other.
Use wallpaper roller with firm downward pressure to thoroughly seal
Pull tape from seam. Other piece of tape along inside seam can also be
removed, but we just leave it inside bag permanently.
Pull wax paper out from under seam
On each end seam, place tape over short section without tape
Clean end seam with acetone, then apply cement to entire seam.
Two sets of hand are mandatory here. Make sure no part of edge touches
another part until glue is ready for contact. Then, carefully align edge and
insure that long seam is centered over mid-point mark on end.
When entire seam is cemented, press seam thoroughly with roller, pressing
down especially hard at seam edges and where the long seam overlaps
the end seam.
Lay another piece of tape 2" in from each end of the bag. I'm using
a 2" side ruler in the photo above.
Clean with acetone and apply glue to the 2" wide section between tape and
the end of the bag that's opposite the hole for the bulkhead fitting.
Carefully fold glued area over and press down, then roll thoroughly
as on previous seams.
As noted previously, it is important to roll on both sides of where the long
seam overlaps this end seam. This juncture is where finished bag is
most likely to leak.
See below for an easy solution to leaks.
Before gluing end of bag near hole, install bulkhead fitting into hole.
Rubber washer on bulkhead fitting goes on inside of bag. Plastic nut goes on
outside as shown. Tighten nut securely by hand.
Flotation bag complete except for valve
Valve parts include (left to right) 1/2" threaded PVC ball valve,
1/2" PVC close nipple, 1" x 1/2" PVC reducing bushing. Teflon tape in background.
Bushing goes into bulkhead fitting, pipe nipple goes into bushing and ball valve
goes on other end of nipple. Teflon tape works well for all the threads
except between bulkhead fitting which has NPS (straight) threads and bushing
which has NPT (tapered) threads.
For connecting those parts, use a PVC compatible pipe thread compound.
To inflate, screw 1/2" PVC adapter (1/2" male pipe thread x 1/2" barb) into ball valve, then
slide piece of 1/2" non-metallic plastic conduit over barbed end. Connect to
hand pump, or inflate a large plastic garbage bag, then wrap neck of bag around
conduit and squeeze air into flotation bag.
For quick emergency inflation, connect
conduit to a scuba tank.
To inflate with garbage bag, hold bag open and swing arms
to fill bag.
Then gather bag at neck, insert conduit into bag and squeeze bag.
If higher pressure is desired, connect conduit to hand pump.
Our idea was to use a scuba tank for rapid filling.
Use soap bubbles to check for leaks. The 2 most likely places are where
long seam joins end seam and around the valve. We've had good success with
squirting about 12 fl. oz. of Slime into bag through valve. Inflate bag, then
position it so Slime flows over leak area. Once leak stops, remove
valve and pour Slime back out of bag.
Valve area leaks are fixed by tightening the fittings or applying more
teflon tape or pipe compound.
8 flotation bags deflated for storage. When inflated, they provide approximately
5000 lbs. of flotation.