Here's the pitot tube I made for my RV-3B.
The tube part is 3/16" stainless tube, and the mast is a section of aluminum jury strut extrusion. The mast is 1.125" chord and about 3/8" thick.
The tube is held in mechanically and sealed with JB Weld. Above the 1/8 NPT sensor connection hole, the tube portion of the mast is sealed with JB Weld too. I used the marine version of the epoxy, which is compatible with aluminum.
The whole assembly, which weighs 95.1 grams, is attached to the wing by a plastic clamp just below the tapped sensor hole that screws to a bracket attached to a main rib. Then another small bracket, riveted to the main rib, screws to the hole at the top of the mast, a little hard to see in the photo. The bottom bracket and the plastic clamp weigh 35.2 grams, and the small bracket at the top weighs 10.0 grams.. In U.S. units, that's 4.95 ounces for this and the rest of the bracketry and nutplates.
In this photo, there's still some clean-up and smoothing to do. This photo didn't show it, but it's what I found when I switched from TinyPic to Imgur.