JOHN OSULLIVAN wrote:
>
>   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.

I didn't know anybody still tried to put soldermask over reflowed
traces. Soldermask over bare copper has been the norm (due to the
reasons you detailed in your message) since before I was designing
boards (8 years).
--
Cap'n Jay the Red
"In wildness is the preservation of the World" - Thoreau