Lots. I used mirrorcoat for quite a while. Mirror is a very hard brittle finish. Sometimes it cracks when bounced off of rocks. I have moved onto clear coat. A little more flexible, for lack of a better word. It is the best for plugs IMO, and many others, and also the most aggravating. Temperature, above 70 to dry. Mix exact. Use a sponge brush. Thin coats, it is a very thin product to begin with. I usually do 2 coats, letting the plug dry for 24 hours before next coat. You can do a lot of plugs with one bottle of each. You have to spin them for 6 hours min. though. I also use it for sealing my plugs too. Heat plug in oven at 225 for 15 min. then put on rubber gloves and spread all over. Use pipe cleaner for thru holes let soak in for 10 min and wipe away all, I mean all, excess. Not as messy as it sounds. Takes primer nice and you will have a very hard product after you finish clear the outside. Like anything there is a learning curve involved. Takes some practice but for me the best epoxy product for the job. Good luck. Paul