Glassblowing has been around for thousands of years, and we see examples of it every day. From neon signs to Murano glass to Chihuly glass exhibits. Less well known but very important to science is the art and craft of scientific glassblowing which is the process of creating glass apparatus used in research and production.
Over the years I have had the good luck to be working at universities on one or another type of vacuum chamber related instrument where some glass to metal seal was damaged but was able to be repaired by the resident glass blower. More recently it seems that many of the glassblowers at universities are retiring and not being replaced. So, to an extent, scientific glass blowing is becoming a nearly lost art as this interesting article on the History of Glassblowing explains.
But all is not lost as there are still scientific glass blowers who are handing down their glassblowing expertise to those who will carry on the tradition.
Also, there are some schools which offer glassblowing courses such as Salem Community College.
Listed below are some companies that provide custom scientific glass blowing services. These companies can also repair broken glass to metal seals.
Finally, The American Glassblowers Society has a Find a Glassblower link that lists glass blowers from different parts of the USA. https://asgs-glass.org/#