To address this I have recently purchased some of the Rapid Repair Resin and Hardener as this claims to be much quicker as it was designed for us trackside by F1 teams.  I have mixed the resin carefully following the rations (I use digital scales) but have found that, despite the room I am working in being kept at approximately 25 degrees the resin is taking almost as long as the EL2 to tack up and even 14 hours after the repair has been completed, when the shrink tape is removed it is still surface tacky/greasy to the touch and the resin hasn't fully cured.