FAQs

If your flask has a neck with a standard taper ground joint, measure the inner diameter at the top of the neck in millimeters, then measure the overall length of the neck in millimeters. SciMac Stocks all PTFE Stopper sizes to fit every Flask.

To measure the flask opening use a ruler with millimeters and measure the inside diameter of the opening and the length of the ground joint section of the neck.

If you have the manufacturers’ part number of your flask, we can help you find the precise stopper size. Email or Call Customer Service for help finding the correct size.

If your flask has a neck with a standard taper ground joint, measure the inner diameter at the top of the neck in millimeters, then measure the overall length ground joint section of the neck.

PTFE Stopper sizes conform to ASTM International standard ASTM E675-02 specification for International Taper-ground Stopcocks and Stoppers.

Stopcock plugs are measured in millimeters, straight bore stopcocks are measured at the cater of the bore and the lateral length of the tapered section of the plug. Sizes 11/25, 15.2/30 and 16/35 are standard sizes although may be referred to by the diameter of the center bore 11/25 has a 2mm center bore, 15.2/30 has a 4mm center bore and a 16/35 has a 6mm center bore.

Stopcock plugs are measured in millimeters, the first part of the size refers to the diameter of the stopcock measured at the center of the bore. The second number represents the lateral length of the tapered section of the plug.

Glass Flasks with a straight neck generally use a rubber or silicone stopper. If you want to purchase a PTFE stopper to fit the straight glass neck measure the opening of the neck and look for a stopper that will have a similar diameter 1/3 to 2/3 down the taper. PTFE is a hard material therefore it will not compress like a rubber or silicone stopper does. Email or Call Customer Service for help finding a suitable size.

You can search our website with another business’s part number for many of our products. If your search doesn’t turn up a comparable part email of call customer service for expert advice on locating the part or component you need. SciMac has been producing PTFE components for major glass manufacturers for over Sixty years. It’s possible the part you need was made in our factory originally.