[harryn]

Thank you for the links and comments.

I actually have made a number of power LED projects, but in those cases I had some special tricks to move heat separate from the board. For this project, those methods are not available - and for once I am trying to follow industry practice - except in one area. The path I am attempting to follow is the Lumileds thermal recommendations board design data sheet. The challenge I have, is that small runs often don't included plated through holes - at least when cnc drilling is used.

I have used silver filled epoxy before - similar to what the other guy had done. Mcmaster sells it as do others. The problem that the guy in the link has is that he didn't cure it sufficiently - at least so it appears. It also has mediocre thermal conducticity, in spite of what we wish. If this project were for me, I could use it, but for this project, the economics do not work.

Back to the original question I guess:

- Is it possible to use solder paste alone to make a conductive bridge between top and bottom copper boards or is this just crazy? By this, I mean to squeegy on the solder paste - perhaps with vacuum if needed, then melt it to form a conductive bridge.

Alternative 2 - drill the hole down from the top - stop on the bottom copper - and then fill the hole with paste - then melt it to make the connection.

Thanks

Harry