7 November 2012

Casing test #4 - another radial ------- UPDATE at bottom pf page

This time the splitting is fixed! :>D ......But now there is a lot more wrinkles :>/
Oh well. Maybe better next time.

Someone asked about the materials used, so they are shown here as well.

The thread is a 8-oz spool of size-33 nylon, diameter = .008" (.2mm) the whole spool is about 6900 yards. The spool shown is a new spool; I have almost used up one entire spool so far with all the testing done.... The casing shown inflates to ~1.25 inches wide on a typical rim, and consumes about 600 yards of thread.

The steel cable is 304 stainless .009" diameter, the roll is 1150 feet. Each tire bead (for a 559mm tire) uses about 17.25 feet per side, for three wraps. So ~35 feet of steel bead wire per tire.

The rubber is in the 1-gallon bucket, it looks like thick white paint. How much rubber is used is difficult to say, maybe 1/2 cup? (120ml) The plain rubber starts out white but turns colors as it ages--first slightly yellow, then a cream/light brown.

[image #1 below]

This time about 1/3 of the casing turned out good, with no wrinkles and consistent width (+/- .5mm I'd say). The rest of it makes it unusable though. I did not pressure-test it because it must dry 3 days first. And I likely won't, because it may fail just because of the wrinkles.

UPDATE - I tried pumping it up, because why not? It can't be fixed, and will only get thrown out eventually anyway. I got it up to about 50 PSI and the wrinkles began to make ugly stretching noises and all pull out, in a very-not-confidence-inspiring sort of way.

Pic #2 below--a somewhat-frightening overview

Pic #3 below, showing the pump gauge. A bit of air leaked out while I was fumbling with the camera, so it does not quite say 50 PSI here. And I didn't check it with another pressure gauge, so I can't be certain it was at 50 PSI.... but the needle was halfway between the 40 and 60 when I stopped pumping.

Pic #4 below - after the tire was deflated again, the formerly-smoothly-wrinkled areas were wrinkled in an entirely new way. They appeared blistered.

Pic #5 below - another view closer of a wrinkled spot, after deflation. I did find two small splits in the casing, after the tire was deflated--BUT--they were not big enough for the tube to get out, and both of them occurred in one of the twisted/wrinkled spots. They did not occur in the "good" sections.

I am quite pleased. I consider this a significant success.
I left it inflated for about ten minutes. Both beads held on completely all around the rim on both sides, that I could see.
Also note that MOST of the tire held just fine--it is only the wrinkled spots that bulged out ugly.

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