Stan's Rim Tape by NoTubes can be used to seal many rims air tight. Also it can be used as a light weight rim tape. 

Features - Stan's NoTubes Rim Tape 36 mm

• Creates a permanent, airtight seal over spoke holes
• Completely non-porous vapor barrier seals rim interior from moisture
• Adhesive made of natural rubber sticks where and when you want, but leaves no residue behind
• Low friction surface makes it easy to apply tire beads

Product features

• Width: 36 mm
• Length: 9 meters (enough for (4) 26" or (3) 29" rims)
• Weight: approx. 6 g per rim