Plastic Clamps & Clips

A burette clamp grips a cylindrical tube vertically; a funnel holder is a horizontal ring that supports the cone of a funnel; a Kech clip is a spring-loaded band that encircles a glassware joint. Using the wrong clamp type creates a weak or unstable hold. Identify what the clamp needs to support before selecting.

Burette clamp jaws need to open wide enough to accept the burette or tube diameter. Standard single-jaw clamps suit tubes up to 20 mm diameter. Double-ended clamps hold two burettes simultaneously and must accommodate both. Kech clip size is determined by the joint cone size, not the tube diameter.

Kech clips are sold by joint size: B14, B19, B24, and B29. These numbers refer to the outer diameter of the ground-glass cone in millimetres. Check the joint size marked on your glassware before ordering. Using a clip that is too large will not lock the joint; too small will crack the glass.

Polypropylene clamps and clips can be autoclaved and resist most laboratory acids, bases, and organic solvents, making them suitable for biological as well as chemical setups. Nylon clips are stronger but have limited solvent resistance. Avoid metal-reinforced plastic clamps with strongly oxidising chemicals.

A Kech clip is a spring-loaded plastic clip that locks two ground-glass joints together in assembled laboratory glassware. It prevents joints from separating during reflux, distillation, and vacuum operations where internal pressure or vibration from a magnetic stirrer can cause a loose joint to pop open, spilling hot or toxic liquids. They are essential safety items for any round-flask assembly.

You need a B24 Kech clip for a B24 ground-glass joint. The B number refers to the outer diameter of the glass cone in millimetres. Most standard laboratory round-bottom flasks and condensers use B19 or B24 joints. Check the marking on your glassware before ordering. If you have mixed sizes in the same assembly, you will need clips for each size.

Yes, polypropylene burette clamps are suitable for holding both glass and plastic burettes. The soft inner lining of the jaw prevents scratching of the burette surface. However, avoid overtightening the clamp on glass burettes as excessive pressure can crack the glass. Tighten just enough to hold the burette firmly vertical without lateral play.

Yes, polypropylene clamps and clips can be autoclaved at 121 degrees Celsius. This makes them suitable for microbiology and cell culture setups where the assembled apparatus needs to be sterile before use. Allow clamps to cool fully before handling after autoclaving.

A single burette clamp has one jaw and holds one burette. A double burette clamp has two jaws on a single body and holds two burettes side by side, which is useful for back-to-back titration setups or when running two different titrants simultaneously. Both mount onto a standard retort stand rod.