Rubber & silicone stoppers

Choose by the chemicals and temperature the stopper will meet, and check both on the product page. Natural rubber is elastic and seals well for general use. NBR is often chosen where oils and fats are involved, as with the NBR stopper, black, 94 mm bottom diameter. Silicone is often used at higher temperatures; only autoclave it if the product page says so. CR is a general-purpose option with moderate resistance. For ground-joint vessels, a glass stopper from ground joint glass stoppers seals better. Questions? Ask sales@luminixhealth.com.

Stoppers are conical, so the title gives two diameters: the bottom, which goes into the opening, and the top. Measure the inner diameter of your opening; it must lie between those two values, ideally closer to the bottom diameter so the stopper sits deep enough to seal. For example, the rubber stopper, solid, 49.5 mm top, 40 mm bottom fits openings between 40 and 49.5 mm. For test tubes, choose by tube diameter; tubes are in test tubes. Unsure? Send us your vessel to sales@luminixhealth.com.

A solid stopper simply closes a flask, bottle or tube, as with the standard silicone bung, 29 × 35 mm. A stopper with one or more bores lets you pass a glass tube, thermometer or hose through it, for example for gas inlets, filtration flasks or simple distillation set-ups. The bore diameter must match the outer diameter of what goes through it, so it seals without breaking the glass; wet the glass and insert it with a twisting motion and protective gloves. Hoses and connectors are in tubing, hoses and fittings. Questions? Ask sales@luminixhealth.com.

A standard stopper sits in the opening and is fine for simply closing a vessel. A turn-over flange stopper has a skirt that folds over the outside of the neck, so it seals more securely and is less likely to pop out, as with the turn-over flange stopper, silicone, 30.7 mm. Many are used where you pierce the stopper with a needle to add or withdraw liquid or gas under closed conditions; check on the product page whether the stopper is meant for piercing. Suitable needles are in needles and cannulas. Questions? Ask sales@luminixhealth.com.

A rubber or silicone stopper is pushed into a mouth. The size number corresponds to a top and bottom diameter. Silicone survives higher temperatures and more autoclave cycles. Natural rubber is attacked by oils and by some solvents.

A closure is the part that decides whether a bottle stays shut and whether the contents attack the seal. A ground-glass stopper matches a ground neck. A screw cap needs the right thread and a liner that survives the liquid. Rubber and silicone stoppers push into a mouth. The liner, not the colour of the cap, is the chemical choice. The vessels they close are indexed under ISO laboratory glassware.

This shelf belongs to Stoppers, caps & closures, inside Labware. Luminix Health distributes this range for laboratory use.

The neighbouring shelves are Screw caps & closures, Ground-joint glass stoppers, Lids & seals and Closures (other). The category above this shelf is Stoppers, caps & closures.

Luminix Health distributes this range from the heart of Europe. We deliver across the EU in two to five days if in stock. Standard delivery is free from €250 excl. VAT. Cold-chain goods and dangerous goods under ADR are never included in that free delivery. The terms are in the Shipping Policy. Send a quote request, contact the team, or read who we are. The full brand index is on shop by brand.

The seven catalogues are Labware, Lab chemicals, Lab instruments, Lab consumables, Chromatography equipment, Lab safety equipment and Life Science & Microbiology. If the article is not on the shelf, request a quote.