Hi , i bought the 4 cavity do-it senko mold and came seem to get 4 good parts without getting denting , pretty sure its not air because when i touch that area i just sinks in … i do heat the mold up to where I have to pick it up with gloves and i top off the sprue as it sinks , and I also dont open the mold for about 3 to 4 mons after injection.. was gonna try angling the mold different so it flows better … any suggestions would be great , Thanks in advance