I like to use glass-filled polyurethane
u-bolts to secure the conduit to the mast
McMaster Polyurethane U-Bolts
They take a bigger hole in the mast section, so some may not like that. With the mast laying on trestles, place the conduit on top/outside where you want it. Mark for the u-bolts and drill. Put the u-bolts over the conduit and into the holes. Glue the u-bolts to the conduit (your choice of glue). Roll the mast so the holes are now down. Pick up the whole mess and slide it inside the mast with the u-bolt legs toward the center. Once it is in the correct position roll the conduit so the u-bolts face toward the holes. It may take a little work
with a coat hanger to get the bolts to come out the holes, but I've never found it that difficult. Snug up the nuts, then cut off the excess bolt. If you like you can put a little glue on the nuts to make sure they don't some undone.
stick is 46', these have been in place for the last 12 years, and nothing has come adrift. The system is 100% plastic, the bolts are UV resistant, don't have to worry about corrosion
except where moisture may get trapped against the mast by the conduit, which will be the same regardless of attachment method. The conduit is clear inside, no rivets, easy to fish
. IIRC we put the bolts 5 or 6 feet on center.
Sorry don't have any pictures.