Tygon® Flexible Plastic Tubing to Tubing Solvent Sealing

Published with permission from Saint-Gobain Performance Plastics Corporation

Permanent Tygon-to-Tygon bonds are easily made by solvent sealing; a useful process when joining lengths of tubing end-to-end or side-by-side, or in fabricating operations such as applying collars or flanges to tubing. The resulting bond is as strong as the Tygon material itself. In addition, a solvent seal eliminates the need for a fitting—solving any problems of leakage at the fitting-to-tubing connection or fitting material compatibility issues.

Basically, the bonding procedure consists of using a cyclohexanone solvent to solvate the areas to be joined, then placing them together in the desired position (i.e. end-to-end or side-by-side) and allowing them to dry.

The solvent can be applied by brush, dipping, wick dispenser, or in any number of appropriate ways. With larger bulkier pieces it may be necessary, before joining the two pieces, to make a second application of the solvent 4 to 6 hours after the first. Solvent sealing is as much an art as it is a science, and there is no rule about the amount of solvent to be used or whether a second application is necessary. We suggest performing several tests on tubing pieces of the same size and thickness—ensuring a strong, neat seal on the final piece.

A good method to join lengths of Tygon tubing end-to-end is to use a shorter "sleeve" of Tygon tubing with an inside diameter equivalent to the outside diameter of the tubing to be joined. After making sure that the ends of the tubing to be joined are cut square, dip them into the solvent, leaving them immersed long enough to allow the ends to soften (only a few seconds are required). Then, slip these two ends into the "sleeve" from opposite ends until they touch. After approximately 12 hours of drying time, the joint will have reached its full strength.

Cyclohexanone Solvent Handling Precautions:

  1. Work only in a well-ventilated room, as fumes are hazardous.
  2. Do not swallow, drink, or ingest the solvent. If ingestion occurs, drink plenty of water and seek immediate medical attention.
  3. Protective gloves and eye protection are recommended. Should skin contact occur, wash affected area with soap and water immediately. Irrigate eyes thoroughly with water.
  4. Keep away from heat, sparks, and flame. Store in a cool, dry place.
  5. Work on a metal, porcelain, or glass surface which is impervious to attack by the solvent.

Tygon is a registered trademark of Saint-Gobain Performance Plastics Corp.