I have a 15m speed2 silver arrow with skytex fabric (nylon) that is at the end of it’s life and a good candidate for testing coatings. The wingtips won’t fully inflate even with many speed-system/ring-line adjustments. Tested it on the ground with a fan to verify it won’t fully inflate due to the fabric being pores. Fabric could be stretched out, but when I fly and swing the kite to inflate the tips the shape seems fine. Shame because the kite is otherwise in good shape. The previous owner coated it once with nickwax, which may have helped waterproof but probably not the porosity. With nothing to lose a few years ago I washed it (made the worst bridle tangles ever) and coated it with 5 cans of silicon spray both sides. Easy to do, quick dry, fan tested and fly tested, no change. Then I coated it with water based polyurethane (Tent Sure). Harder to do, slower to dry, fan tested and fly tested, no change. Then I ran out of patience and put it in a box in the garage. So along comes this thread with styrene butadiene rubber (SBR) coating. Why not?
I found that SBR is a mixture of approximately 75 percent butadiene (CH2=CH-CH=CH2) and 25 percent styrene (CH2=CHC6H5). Like natural rubber, SBR is swollen and weakened by hydrocarbon oils and is degraded over time by atmospheric oxygen and ozone. Unlike natural rubber, it tends to harden with age instead of softening. The most important limitations of SBR are poor strength without reinforcement by fillers such as carbon black (for tires), low resilience, low tear strength (particularly at high temperatures), and poor tack (i.e., it is not tacky or sticky to the touch).
I found Amazing Goop is Solids 45% by weight (42% by volume). Styrene Butadiene Copolymer 30-60%, Toluene 30-60%, Solvent Naphtha (Methanol?) 10-30%, but the concentration is given as a range is to protect confidentiality or is due to batch variation. Styrene and can be produced from toluene and methanol. Butadiene usually is polymerized to produce synthetic rubber.
I found for thinning paints and varnishes, xylene can be substituted for toluene where slower drying is desired. Xylene is a generic term used to refer to three closely-related chemicals: meta-xylene, ortho-xylene, and para-xylene Xylene is a sweet-smelling liquid, colorless, quick to evaporate and very flammable. It is used in industrial processes for rubber and plastics manufacturing. Xylene will evaporates easily in the air and is broken down by sunlight into other less harmful chemicals. Best of all it’s cheap at the hardware store.
Last, I found that nylon is unchanged by Toluene, Xylene, and Naphtha Solvents.
So I’m planning to giving the old S2SA another chemical sponge bath to see what happens, and try not to inhale