Shrinkflex PTFE Heatshrink Tubing

PTFE heat shrink tubing is available in 2:1 and 4:1 shrink ratios, and is widely used in military applications (AMS-DTL-23053/12), industrial, biomedical, chemical and analytical sciences because of its high continuous use temperature (250°C), and outstanding chemical resistance.

PTFE heat shrink tubing is the most difficult of the three fluoropolymer materials to shrink due to its extremely high shrinking temperature (325-340°C). You can use a heat gun or welding torch to shrink TFE, but these methods have a tendency to cause the material to overheat in small areas, while under-heating other areas, causing uneven shrinking and potential burning of the material. The most reliable method for shrinking PTFE is the use of a controlled temperature oven; however this is impractical with large harnesses or temperature sensitive components.

A few notes on shrinking PTFE:

1. Always assure good ventilation in the immediate work area prior to beginning the heat shrink process. Fumes may cause nausea and dizziness.
2. It is imperative that the tubing be heated uniformly until it becomes clear (gel state). This transition from crystalline to amorphous must take place, since shrinkage will only occur during recovery from the gel state (re-crystallizing).
3. When using a mandrel to shrink the tubing, it is important to pre-heat the mandrel to assure even and uniform shrinkage.
4. If the tubing begins to crack, chances are you overheated the material.
5. Also, higher shrink ratios will require higher shrink temperatures.

RoHS Compliance PDF 234KB

UL Card PDF 44KB

2:1 Ratio

* CUSTOM SPECIFICATIONS AND TOLERANCES UPON REQUEST
* AMS-DTL-23053/12
TW=AMS 3585
SW=AMS 3586

4:1 Ratio

Four foot sticks of heat shrink tubing are standard packaging lengths. Shorter pieces, longer pieces, or cut pieces to size are available upon request. Extremely long continuous lengths are sometimes available depending on specifications. Inquire for feasibility and pricing.

UL File #E64007 / CSA File #082582.

View Measurement Conversion Chart

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Limiting Oxygen Index (LOI)

The ratio of how much oxygen - as compared to other gases - needs to be present in the air surrounding a particular material in order for that material to burn. The fact that Earth's normal atmospheric air contains around 21% oxygen is used a reference point when materials are classified into burn categories that are based on Limiting Oxygen Index. Substances that are combustible in air containing less than 21% oxygen are considered flammable, while those that burn in the range of anything greater than 21% but less than 28% are typically labeled "slow burning". Any material with an LOI that exceeds 28% is classified as self-extinguishing.

In the table below, you'll find a list of polymers commonly found in our heat shrink tubing and braided sleeving products, along with their LOIs and the burn categories each falls into.