The first part of the answer is why do we use glue-ins. The Marine environment is a brutal one, especially for metals. Any time you have 2 pieces of metal touching (hanger and bolt), especially if they are 2 different metals, there is a possibility of corrosion. Salt
water speeds this up because it acts as a conductor and speeds the chemical reaction that is corrosion. This was most notable in Thailand where burly 1/2 inch expansion bolts were placed in sea cliffs (much like Flat Rock) and were rusted out inside one year. There is a theory that the chemical composition of the rock lead to the corrosion. Using a one piece glue-in avoids this contact of two metal, and the glue makes a chemical bond with the rock so water can't get
in and cause trouble. It is the way to go for sea cliffs.
So why the hell did I use an expansion bolt? There are multiple pieces and are not as strong as a glue-in. Whats up? Well what I put in was a stainless steel Triplex Bolt from Fixe. Stainless steel is the least like to corrode and the Triplex has only 3 pieces (hence the name). What the real beauty of this bolt is that is is removable! I can easily pound this thing
in and pop it out anytime I want. It is a 1/2 inch bolt which is bigger that the standard 3/8's found in most climbing areas. It uses the same size hole as the glue-ins so when the time is right, I will pop out the Triplex and replace them with glue-ins. So when you see the expansion bolts on Candy, don't freak out. They are solid and can be replaced with glue-ins at any point. I am going to leave them for a while to see how they mature.