GL Threads
GL threads are externally threaded glass (and plastic) fittings.
They come in a range of sizes, some simply tooled on borosilicate tubing, some molded on bottles.
The inside diameters of the glass show the maximum passthrough.
There are closed caps, open caps, septum seals, and sealing rings for all sizes.
The sealing rings accommodate tubes or electrodes at nominal diameter ± ~ 1 mm.
Dimensions in millimeters.
| Size | ID | tube (bottle) OD |
Available sealing IDs |
| GL14 | 8.5 | 12 | 6 |
| GL18 | 10.5 | 16 | 6, 8, 10 |
| GL25 (tube) | 18 | 22 | 8, 10, 12 |
| GL25 (25 ml bottle) | 14.3 | (36) | 8, 10, 12 |
| GL32 (tube) | 24 | 28 | 10, 12, 14, 16, 18 |
| GL32 (50 ml bottle) | 17 | (46) | 10, 12, 14, 16 |
| GL45 (tube) | 35 | 40 | 26, 32 |
| GL45 (100 ml bottle) | 30 | (55) | 26, 32 |
| GLS80 (500 ml bottle) | 65 | (102) |
Some of the ways of connecting with GL threads are shown here for GL14 options; the larger sizes have similar possibilities.
There are teflon inserts for GL14 that hold and seal 1.6 mm (1/16"), 3 mm, 3.2 mm (1/8"), and 6 mm tubes or electrodes.
There are a number of off-the-shelf options for sealing rings, septa, inserts, hose barbs, etc. These components will seal to a variety of materials.
GL80 cap with GL18 threaded insert
GL14 thread sealing 1/4" insertion
GL14 thread with flexible tubing through sealing ring