approx 24 hours but more specifically;
Once the ProFlex is applied, the Liquid EPDM must be applied normally within 24-48 hours to ensure proper adhesion. Once the ProFlex is applied, depending on your temperature you may be able to apply the Liquid EPDM the same day or need to wait until the next day. We suggest you check the setup of the primer about eight hours to determine how quickly it is setting up; based on the area of the country you are in and the time of year. The ProFlex needs to be tacky when applying the Liquid EPDM. If the ProFlex is tacky but does not pull up when you walk on it that is the ideal condition to apply the Liquid EPDM. If the ProFlex is allowed to dry the Liquid EPDM will not adhere properly. This will necessitate you waiting until the ProFlex has fully dried and then sand the primer and reapply. Should the EPDM peel off from the primer this situation resulted from letting the ProFlex dry. Also after mixing the primer (Part A and Part B) we suggest you pour it out on the area to be coated. This will extend the pot life of the material it will last longer if out of the can.