What I did with my clear tubing(may be too much hassle for some of you guys) was to get some hot water & toss in some RIT fabric dye. Sucked it up throughout the length of the hose, then dropped the whole thing(with dye inside) in the container. When I took it out(bout an hour+), the tubing had been stained to completely black. Ran water through it to get rid of the dye & rinsed off the outside. Since the dye permeated the tubing material, it's permanent and does not scratch off. Trying it with cold/room temperature water resulted in a grayish color - pretty cool, but not what I wanted.
If you make the water hot, you may be able to get by with just staining the outside. I did for one of the shorter ones & this makes it a lot easier because it's a pain in the butt to get the moisture out of the insides
. Since I have more float tubes than I'll ever need, I stopped my experimenting, but may start again to make a few long ones. I had to cut my only long one in half because I mistakenly burnt the middle on a stove(don't ask, the story is even stupider than you'd think)
One thing I found is that if you use orange dye, it'll make the tubing look just like kelp!!! Great if you want camoflauge, but not in my situation. I was trying to make it very visible(thinking orange is bright - apparently only if it's phosphorous based as Sven pointed out in a thread many moons ago), but since the result blends so well, I lost my speargun for over and hour at Ocean Cove as I swam around in circles trying to find my float line so I could pick off the abalone I marked. The line matched so well with the Bull kelp stalks, I swam past it several times & only by dropping down 30 feet & swimming around in circles did I finally see the white butt/handle of my gun
I got my tubing at Orchard Supply & Home Depot & my dye at Walmart. For the ends, I didn't have time to order any swivles, so I plugged the ends with a good amount of marine silicone(don't think there's any real difference), looped a swivel in a small section of bloodline/nylon/spectra(experimented with different ones), then inserted the ends of the line into the tube & secured via a couple clove hitches with waxed thread. On a couple I used heat shrink tubing to make it look smooth, but found that a couple wraps of electric tape worked just as well & would be a lot more durable. For my short marking lines(mostly for abalone, rock guns), I didn't thread line through it & tested it with some tug of war with a friend just for fun. The longer ones have a nylon core.
