Heat Shrink Tubing Solutions

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Markel PTFE Heat Shrink Tubing

Markel : Heat Shrink Tubing : PTFE Heat Shrink

Choosing the Right PTFE Heat Shrink Tubing for Your Application

It is important to select the optimal size and shrink ratio for your particular application. The inner diameter of the expanded heat shrink tube should conform as closely as possible to the OD of the part being covered while still allowing an easy insertion of the part into the heat shrink tube or sleeve. The heat shrink ratio is best determined by the shape of the part being covered and the degree of compression desired. More irregular shapes will require a higher shrink ratio to conform better to the shape. If a high degree of compression is required, a higher shrink ratio is beneficial.

 

Both Markel FEP and PTFE Heat shrink tubing are offered in a variety of diameters, wall thicknesses, and shrink ratios as shown on the accompanying tables. If you have questions about your particular application, do not hesitate to contact a Markel engineer.

PTFE Heat Shrink Tubing

Heat shrinkable PTFE tubing is activated at a temperature of 650°F (343°C). The highest percentage of the size reduction occurs rapidly on reaching this temperature, but the process continues slowly through the cooling cycle after heating. Exact conditions are best determined on an application specific basis. Both the nature of the part being covered and the design of the oven or heat source will alter the required time and temperature to recover. It is important that for optimal results, the heat is applied evenly to all sides and that the part is unconstrained so that it is free to move longitudinally. Larger or heavier parts will require longer times as they will act as heat sinks. It may be beneficial to pre-heat all or part of the item to be covered to facilitate rapid and uniform shrinkage of the tube.

Whenever working with any heat shrinkable product, ensure that there is good ventilation around the work area. Fumes from any fluoropolymer heat shrinkable tubing should be avoided as they may result in dizziness, nausea, or headaches.

 

Ovens (as opposed to heat guns) are the best way to apply heat shrink tubing uniformly as they offer the most uniform temperature profiles. Care should be exercised to ensure that in the case of convection ovens, the air velocity does not dislodge the heat shrink tubing from the part to be covered.

Application of Standard 2:1, ThinWall 2:1, and 4:1 PTFE Heat Shrink Tubing

1. The Markel PTFE Heat Shrink Tubing should be trimmed to length and tested for fit prior to exposure to heat. The tubing should slide easily into place, but have enough of an interference fit to remain in place during the heating process.

2. Ensure the part to be covered and the inside surface of the heat shrink tube are free of dirt, dust, or particles.

 

3. Markel PTFE Heat Shrink Tubing should be heated to 650°F (343°C). The duration of the heating process will vary depending on oven conditions and the geometry of the part, but excessive heating should be avoided.

 

4. The part being covered by the heat shrink will act as a heat sink and may impact how the tubing shrinks. If you notice wrinkles, uneven shrinkage, or other signs of uneven application, consider preheating the part to an elevated temperature, but remaining below the heat shrink temperature referenced above.

 

5. The final dimensions of PTFE Heat Shrink Tubing will depend on exact clearances with the part covered. If there is little room for radial recovery, the tubing will tend to contract longitudinally. Too tight a clearance may also result in splitting the wall of the PTFE Heat shrink.