I recently purchased the PIKO Refinery Burn Off Plant. When I tried to glue the two large baseplates together, the glue doesn't hold because the sides of the plates are not vertical (they slant inward on all sides) and thus they don't fit flush. My first thought is to sand them down flat and try again. Is this the best solution? Is there another, better on that I've overlooked? Anyone who's solved this problem - please help!