Thanks for the help so far .
Reason for asking is, it seems to be a dieing craft here in the UK with only a few specialist companies doing it and many gunsmiths preferring to do hot bluing with the consequential dire disasters to soldered barrels and ribs. A friend now has one of his guns back at the gunsmith who blacked his barrels a few months ago and the gun now has loose ribs . Gunsmith will not accept liability.
As many of you know , cold blacking is a relatively simple process only requiring , chemicals, time, and more than a little patience.
