Heat Shrink Tubing Recovery Process
PTFE Tubing is the most difficult of the fluoropolymers to work with and shrink due to the extreme temperatures needed to start the shrinking process. The most reliable way to shrink PTFE is in a controlled oven environment. Shrinking can be accomplished with a heat gun or open flame but it is not recommended because of the tendency to overheat the area in a single area while the remainder of the material remains to cool to shrink.
Extreme caution must be exercised in heating the PTFE during the shrinking process. The PTFE Tubing must be heated evenly to the gel state to insure complete recovery. PTFE shrink tube will become completely clear when it reaches it gel state at about 624°F. After the material has reached its gel state do not continue to heat, the material is now ready to begin the cooling and shrinking phase. PTFE will start to recover once the cooling process has begun and the material comes out of its gel state. Once the material has completely cooled the PTFE’s appearance will be its normal milky white color.
PTFE Heat Shrink Tubing will tend to split longitudinally if tubing is not allowed to recover to about 75 % of its expanded diameter or if it is over heated during shrinking.
How To Shrink PTFE Heat Shrink Tubing
ALWAYS assure good ventilation in your work area before starting the heat shrink process. Shrinking with direct flames or burning of Fluoropolymers may cause dizziness and flu like symptoms.
| Resins | FEP Tubing | FEP Roll Cover | PTFE Tubing | Dual Wall PTFE / FEP |
|---|---|---|---|---|
| Working Temp. | 400° F | 400° F | 500° F | 450° F |
| Shrink Temp. | 230° F | 350° F | 624° F | 624° F |
| Heat Guns | Preferred | Preferred | Not Preferred | Not Preferred |
| Ovens | Preferred | Not Preferred | Preferred | Preferred |