They are surprisingly different. Quicksteel sets in 5 minutes, cures completely in an hour. JB Weld takes hours to set, let alone cure, and even after that it doesn’t seem to stand up to heat as well. (JB Weld has a putty that cures quickly, but is not rated for very high heat or strength.) I have both in the house, but for anything involving heat or pressure I use the Quicksteel.
