as JB said, the rim tape had not properly bonded to the rim, prior to putting on the tire with sealent. The Notubes website has got a good video of how to do it all properly. In a nutshell: take the rim and run a piece of scotch brite pot scourer inside the rim over the spoke holes. this cleans the surface and roughens it very slightly. wipe out dust that forms from the scourer. Apply the sticky yellow rim tape, making sure you pull fairly hard to stretch it in place, finishing with a 12-15cm overlap. using a sharp scribe, punch a hole in the tape over the valve hole, and then remove the yellow tape from this hole using a small circular file, in a pushing down motion, not pulling up. pulling up lifts the tape and can split it. Fit your tire onto the rim, and install a tube. pump up the tube to 3.5bar and set it aside for 60mins or more. (this compresses the tape onto the rim properly so that it seals better.) remove the tube, install the tubeless valve, tighten it down properly. install the tire, clipping in the bead to one side, and 90% of the bead on the other, and add 80ml+ of sealant. fit the rest of the tire bead into the rim (tire levers may be required if the fit is tight) inflate the tire to 3.5 / 4bar. this may take some massaging of the tire to get the bead to 'clip in' if you are using a small compressor for a 29". you may need a large compressor eg at the local BP or engen if the 29" tire fit is loose. for a 26", a bomb usually works well followed by a hand pump to get to 4bar. Soapy water is sometimes applied to the bead outside edge to get the tire lubricated so that it can seat better, up to you. the soapy bubbles indicating leaks around the bead edge are more useful though in helping you seal the tire. The next stage varies, but merely spinning the tire is not good enough. I find the Joes No flats method works well, although its time consuming. hold the wheel just off horizontal with the valve at your chest and the furthest point of the wheel down in front of you. shake the tire forward and back in small movements for the count of 20 seconds. the sealent should be lying over the internal rim/bead junction and the shaking should agitate it into the joint between the two. rotate the wheel 10-20 degrees to the left and repeat the 20 second shake. continue for the whole wheel, then flip it over and repeat for the other side. once done, yours arms and shoulders should be feeling the workout, put the bottom edge of the wheel and tire into waterin the bath so that it is submerged, and any leaks in the sidewall or bead rim junction are revealed. (very little if using a UST tire) repeat the shake over the area that had bubbles escaping to seal it up. after 3-4 weeks add sealent to the tire, as the latex in the sealent will have bonded to the inside of the tire through use, or collected into those neat alien rubber balls inside the tire. ride and enjoy.
