Homebrew PCBs

New to the group...

Donald H Locker <dhlocker@...> writes:
>  Temperature seems to depend on the toner, but somewhere around 275F to
>  325F seems to work pretty well, near as I can tell.

I tend to use 345F or so for HP toners. Most Brother toners need
360-375F.
[DJ Delorie]

I wonder if those temps are absolute or if they depend of you're 
using an iron or a laminator.

To my question:

I'm using a modified laminator to transfer the toner to the copper.

I'm using a Brother HL-5170DN to print to thin glossy (not photo) paper.

The printing goes just fine, as does the toner on the copper.

But after etch, it looks like there were some pinholes in the toner: 
there are places in the copper where the copper is etched through in 
a point or right across a trace. If I were to tin the copper it would 
probably be OK to use.

What is the cause? The toner adheres just fine to both the paper and, 
apparently, the copper.

Suggestions?

Thanks,
Dave