I have been making press fit type connectors for GC for more than twenty years and the reasons these otherwise convenient products sometimes leak really hasn’t changed. The largest difference in press fits, both historically and currently between manufacturers, is the angle of contact between the column and the press fit wall. The lower the contact angle is the longer length of column that will form the seal. The longer the length of the seal the more tolerant of irregularities in the column cut that the connector will be. InnovaQuartz makes the lowest angle universal quartz press fit connectors available: twice as much to three times as much column length is compressed in IQ’s Pres2fit™ seals so that even “bad” column cuts seal extremely well.
The earliest press fits were made with a fan flame torch to form an hourglass like bore in a quartz tube, but the restriction that resulted was shaped like a trumpet’s bell such that the contact angles for large bore columns was far higher than that for small bore columns; a 0.53mm column contacted a roughly 5° wall where a 0.25mm column contacted closer to the center where the wall was around 2°.
To correct this problem, my company (InnovaQuartz) developed a laser-based method for computer-controlled collapse of the quartz tube bore resulting in Linear Taper™ connectors where all column diameters contacted at about 2°. We patented the process and enjoyed a monopoly for a couple of decades, where we made all of the quartz press fit connectors sold by GC column companies, big and small, foreign and domestic. Some leaks were still reported from time to time – and we examined returns when available – but these were uniformly labeled “bad column cuts”, not bad connectors.
It wasn’t until we got our own GC and personally experienced leaking press fits that we started looking at the problem from the proper point of view: it wasn’t bad column cuts – it was connectors that were intolerant of even minor defects in column cuts. With a new perspective, we set out to solve the problem…
Our current solution is not the end of the story; we are still working on other ideas. The Pres2fit™ solution IS far better other press fit options, not just the “no leaks guarantee” but for inertness, durability and ease of use. And they will save you money beyond eliminating time wasted in chasing down leaks because they are available with no middleman markup on Amazon, eBay and our own e-commerce website, innovaquartz.com (with free shipping in many cases).