Yep fixed the guage.
Problem can occur in the manufacture. The pipe is pushed too far into the gauge which means it is fairly tight against the internal end of the gauge entrance.* Okay when all is new but if a slight bit of scale builds up at this point it is impossible to clear as the build up on the outside of the pipe and effectively blocks the pipe end. >:(
I was able to make a suitable heat sink and unsolder the pipe. I also noticed that the hole at the gauge end of the pipe was partially closed (cutting process?). This would also contribute to early failure.
I opened the pipe hole* a bit, resoldered the pipe but made sure it was not hard against the internal pressure guage body.
It works.* :)
I would be grateful is a fellow coffee snob who has a broken Giotto plus pressure guage (the half circle type) could PM me as I would like to experiment a bit more. I also would like to salvage the pipe and fittings near the boiler end as I think a pipe with fittings at each end would be much easier to service. The threads are the same.
I am really just playing. I love my Giotto so anything that makes him happy is good for me