PTFE Heat Shrink: Heat Gun or Oven?
This is the first question we get about fluoropolymer shrink tubing, and the answer is grade specific. A normal heat gun recovers FEP and PFA. It does not recover PTFE, and the attempt usually ends in a scorched or wrinkled tube.
Why the tool matters
Recovery is a temperature event. FEP and PFA are melt-processable, so they recover above their transitions and hot air reaches those transitions. PTFE is expanded below its crystalline melt point near 327°C and has to be heated above that point, which standard hand tools do not reach reliably.
Equipment by grade
| Tool | FEP | PFA | PTFE | Notes |
|---|---|---|---|---|
| Standard heat gun | Yes | Yes | No | Keep it moving and watch the surface |
| Hot air rework station | Yes | Yes | Marginal | Check the setpoint against the grade |
| Conveyor oven | Yes | Yes | Yes | Even heat along the whole length |
| Bench oven | Yes | Yes | Yes | Best for small parts and long runs |
If you use a heat gun
- Check the grade first. Confirm the tube is FEP or PFA before you pick up the tool.
- Set the air temperature from the grade sheet, not from the highest setting the tool has.
- Start at one end and sweep along the tube. Holding the nozzle in one place produces a scorched band.
- Watch the surface as the tube recovers and keep the nozzle moving until the wall conforms.
- Stop as soon as the tube conforms. Further heat adds nothing and risks the wall.
- Let the part cool before you handle it or check the fit.
When an oven is the answer
PTFE, long lengths and parts with temperature sensitive internals. An oven heats the whole length and the whole circumference together, which removes the wrinkle problem and the local overheating problem at the same time. For a part with a delicate insert, a bench oven on a controlled setpoint is far easier to defend than a hand tool.
Mistakes that show up on the bench
| Observation | Cause | Prevention |
|---|---|---|
| Scorched band on one side | Nozzle held in one place | Sweep along the length |
| Wrinkled recovered wall | Uneven heat around the circumference | Rotate the part or move to an oven |
| Tube will not recover | PTFE attempted with a standard heat gun | Use equipment that reaches the grade recovery temperature |
| Wall pinched over a delicate part | Heat applied with pressure | Heat without pressing and let recovery do the work |
| Glossy or blistered surface | Air set too high | Set the temperature from the grade sheet |
The sweep pattern and the wall behaviour after recovery are the same ones described in our heat shrink tubing installation guide, and the grade table sits on the PTFE/FEP/PFA heat shrink tubing page.
What to send
Send the part diameters, the grade you are considering, the tool or oven available and the temperature at the hottest point. We return the grade and the recovery route for it.
Frequently asked questions
Can I use a heat gun on PFA?
Yes. PFA is a melt-processable thermoplastic and recovers above its transition. Set the air temperature from the grade sheet and keep the nozzle moving.
What happens if I try PTFE with a heat gun?
The tube stays partially expanded, and if you keep the nozzle in one place the surface scorches. You gain a burnt tube rather than a recovered one.
Do I need an oven for long lengths?
For a long run it is the practical route, because the whole length has to reach temperature at the same time. Sweeping a hand tool over a long tube tends to recover one end while the other cools.
How do I stop wrinkles?
Heat evenly around the circumference. Wrinkles come from one side recovering before the other, so rotate the part or use an oven.
Does the tube need to be held during recovery?
No. Heat without pressing. Pressure applied while the wall is soft pinches the tube, and the recovered wall then carries the mark.