I have a project that requires 3 polycarbonate posts to be heat staked. Two of the posts are stacked over sintered brass and the third is staked over ABS. We are experiencing problems with getting the PC to metal posts hot enough to melt the plastic and not have it too hot for the single plastic to plastic stake. Size of the plastic posts are approximately 1/16" diameter. All stakes are into a countersink so the tops can be flush. Any suggestions would be appreciated.