View Single Post
Unread 08-16-2020, 08:32 AM   #9
Member
B. Dudley
PGCA Lifetime
Member
 
Brian Dudley's Avatar

Member Info
 
Join Date: Aug 2011
Posts: 11,072
Thanks: 531
Thanked 19,764 Times in 4,983 Posts

Default

They may have used an acid etch to show the pattern when pairing and assembling tubes.
Just a quick application of acid will show the pattern clearly.
__________________
B. Dudley
Brian Dudley is offline   Reply With Quote
The Following 4 Users Say Thank You to Brian Dudley For Your Post:
Visit Brian Dudley's homepage!