Oops, just noticed my reply seems to have disappeared into the ether.
Looks like C106 is the one to use then, this will be my first loco boiler, (my first loco anything actually) I am apprehensive enough without risking messing it up with wrong material.
Julian, I was not questioning Macc prices, just highlighting the difference between C101 & 106. I have been using Joe for some years now, his prices are keen, good range, good website and the last few orders have been received by return.
If C106 is the correct grade for boiler work I was a bit surprised to see several ME suppliers only advertising C101. Not all copper will be for boilers I suppose but the majority would surely.
Still Joe supplies the correct grade so that is where I will be going.
Thanks to all for advice.
Bill D