sidewall pinhole repair?

Just go to a junkyard and get another wheel with a tire. A used junkyard tire on a steel rim is like $30 here. It's $60 for aluminum because they charge you a core charge here.

A junkyard tire is a lot easier than messing with a sidewall

It's also cheaper than real sidewall repair kits for offroad tires
https://www.gluetread.com