URE-BOND 90 is a two component, slightly expanding urethane adhesive that offers a strong, rigid bond between urethane modeling board surfaces, up to 30# density. It will also bond segments of EPS foam. It slightly expands to fill gaps, holes and micro cracks between board segments for level, predictable bonding. URE-BOND 90 is machinable in 4 hours and sands uniformly to minimize or eliminate post finishing. URE-BOND 90 is also ideal for bonding a variety of other porous and non-porous, rigid substrates. The mix ratio is 1A:1B by volume, pot life is 8 minutes, machining time is 4 hours and full cure time is 16 hours at room temperature (73 °F/23 °C).