Most glassblowers encounter the challenge of making a variant of a commonplace item of laboratory glassware. This, to me, has a special place in the glassblower's repertoire in that it gives one the opportunity to re-examine the fundamentals of the construction process. Routine bench work induces certain intellectual "coasting" -one can almost cease to think too deeply about the "job" when it's the tenth condenser of the week!When a customer ordered a dropping funnel with a full jacket around it, I knew that someone in the workshop was in for some fun, especially as this time they specified a Bibby "Rotaflo" code GP6 tap. Whereas the notion of sealing extra tubing onto the open ends of a key/tapered-barrel stopcock to facilitate encapsulating it into a jacket does not create any technical problems, the major difficulty with any screw-plunger tap is "what to do with the precision bore (p.b.) into which the ptfe plug has to seal?" An additional detail to consider is allowing room for the "knob" of the tap. Containing the thread, to wind in and out.
展开▼
