http://www.cooperhandtools.com/brand...0and%20Use.pdf

I'm doing a little reading on care and maintenance. It looks like I need a new tip. I am unable to tin my tip at this time.

'When oxidation occurs, the tip becomes covered with a black or brown scale, which will not wet with solder - greatly reducing heat transfer.
This is commonly known as "burn-out". Burned out tips are usually discarded, though they may often be cleaned carefully with a fine abrasive and retinned."

Looks more and more like the problem is me and my maintenance of equipment. I'll be ordering a new wedge chip and give that a go, prior to upgrading.

thanks for the help.