[Squibbler]

I'm sure that will hold for a while, but like I said,... that barb comes free with a new radiator. lol. the material is glass reinforced thermo plastic, epoxy does not really adhere to it.

Those barbs are notorious for breaking. So much so that Dorman created a solution.

https://a.co/d/hYU3bsq

The solution you have will hold until it doesn't, but longer term (assuming you don't want to fork out the $$ for a new radiator for now) if/when that fails, use the Dorman.