REGARDING           Solder mask material

With regard to different solder mask material I'm interested in finding out if
some solder mask materials have differnet thermal masking abilities.
The reason I ask is because of a board I am wave soldering which has heavy
copper layers internally, which forces me to pass the board through the
preheat stage (and over wave) very slowly. The board was manufactured using
all over tin/lead reflow. The tin/lead under the solder mask on large tracks
are reflowing grosely and causing the soldermask to bubble/blister and crack
off, failing the infamous 'tape test'.

Any comments.