refractory is called grey soft thermalite blocks broken up and packed round your job nick one of a site it will save u a quid or ask b and q if they have a bust one u can have for nothingThanks for that, looks like Ill need some refractory as well as the torch.
RonA
Unfortunately being retired might have to go the B&Q route, during my 44 years in a steelworks it was laying about all over.refractory is called grey soft thermalite blocks broken up and packed round your job nick one of a site it will save u a quid or ask b and q if they have a bust one u can have for nothing
and different grades of purityWhat size are you soldering? I have repaired copper boilers (for 7.25" gauge locomotives in the past) and that's required a huge propane burner providing background heat and I used an oxy-propane to do the actual silver soldering. Cleanliness and flux is the key. Don't overheat it - that is just as bad. You can also get silver solder at different melting points.
PN