SpudFiles

I bought some Ace Hardware "60 minute epoxy" because it supposedly cures stronger than the regular stuff. I am using it to fill a quarter-inch hole in a pneumatic cannon, and I was wondering if it normally takes longer than two days to fully cure. It is kind-of pissing me off, because I have waited patiently, and it still feels sticky to the touch. It is in my basement, where it is always warm, so I don't see what the problem is. Any input is appreciated.

if it has taken more than 24 hours then you probably didnt mix it correctly. if you are touching it then you are not "waiting patiently"

I once tried to make a piston out of epoxy and parts of it stayed gummy and soft and never hardened, probably from it not being mixed thoroughly).

I have noticed that epoxy usually doesnt get really hard till later than the package advertises. But, if yours doesn't fully harden within a full day, It probably wont ever harden. make sure you are pretty exact with your even portions when mixing and make sure it is mixed completely.

Also, from what I have read on the packages, the locktite is rated to take higher pressures than the ace stuff, at least all the stuff that was on the shelf at my ace.

Some Epoxy also produces what is known as "amine blush". It kind of sweats out a thin layer of stickiness in some conditions. Generally you can wipe it away and see if it is solid underneath.
Edit: Actually Google "amine blush" if you want all the info.

wait for JSR

If it's truly staying sticky, I'd say that's because you didn't use enough hardener. Most of the epoxies I've used stay somewhat gummy to the touch after curing, but never sticky.

Why couldn't you have just tapped in a 1/4" plug into it and have been done in 3 seconds?