Recovering PTFE, FEP and PFA Heat Shrink Tubing: Temperature Window and Traps
Engineer's Guide · 2026-09-16 · 5 min read
A polyolefin sleeve forgives a wandering heat gun. A fluoropolymer sleeve does not. The recovery window for PTFE, FEP and PFA sits at temperatures where the tube has already lost most of its margin, and the failure it produces is not a visible burn. It is a wall that thins unevenly, grips the part with a wrinkle on one side, or cracks three weeks later in a chemical cabinet. This guide covers the practical part of recovering PTFE, FEP and PFA heat shrink tubing: the window per material, which heat source to use, the order to shrink in, and the six traps that account for most returns.
The recovery window is not the service temperature
These are two separate numbers and mixing them up is the first mistake. Service temperature is what the recovered sleeve survives for years. Recovery temperature is what it takes to make the wall move. On fluoropolymers the gap between the two is wide, because the polymer is semi-crystalline and only relaxes the orientation above its melt region.
| Grade | Recovery behaviour | Continuous service | What drives the choice |
|---|---|---|---|
| PTFE | Needs the highest heat of the three; a normal hand heat gun will not seat it | Up to around 260 C | Temperature ceiling and near-universal chemical resistance |
| FEP | Recovers at a lower temperature than PTFE and is easier to process | Up to around 200 C class | Optical clarity, easier recovery, lower cost than PFA |
| PFA | Recovers at a high temperature, between the two | Up to around 260 C | Highest purity, lowest ion and particulate release |
Heat gun, oven or hot plate
The heat source follows the part, not the material. A straight length of tube over a wire can be recovered with a good industrial heat gun. A sleeve that has to close onto a fitting inside a housing, or a sleeve with a wall below 0.2 mm, is an oven job.
- Industrial heat gun with a reflector nozzle: correct for open assemblies and field work. Keep the gun moving and heat the whole circumference, not the side facing you.
- Convection oven: correct where the sleeve has to shrink evenly around a fitting, where several parts are batched, or where a thin wall would tear under a directed hot spot. Set the oven above the recovery window and hold a short dwell.
- Hot plate or heat tunnel: correct for straight runs in a repeat process. It limits the heat to the contact face, so it suits round tube over round wire and nothing else.
- Hot air rework station: usable on sensor and probe assemblies where the mass is small and you need a controlled nozzle. Stop when the wall goes clear, not when it looks hot.
The order to shrink in
Fluoropolymer shrinks fast once it starts, and the air underneath has to escape ahead of the shrinking front. Working the wrong end traps it.
- Slide the sleeve into position and note where it has to end up, because it will not move once it grips.
- Start at one end and work along the run in a single direction. Direction matters less than consistency: reversing halfway creates a bubble that has nowhere to go.
- Heat the full circumference as you advance. A wall that grips on one side and stays open on the other is a pressure point, and pressure points crack first.
- On a fitting or an irregular profile, pre-warm the whole sleeve until it softens, then let it close. Chasing a cold sleeve around a shoulder with a hot spot tears it.
- Stop at full recovery. The wall goes glossy and sits flat against the substrate. Extra heat at that point only thins the wall.
Six traps that ruin a fluoropolymer wall
| Trap | What happens | What to do instead |
|---|---|---|
| Sizing by supplied diameter | The tube recovers to the wrong final ID and cannot be reworked | Order by recovered ID and wall thickness, never by expanded size |
| Overshooting the temperature | Wall thins, goes translucent and loses mechanical strength | Hold the top of the recovery window, not the middle, and stop at full recovery |
| Heating one spot | Local burn, then a split at the burn when the part flexes | Keep the source moving; heat the circumference |
| Skipping the surface clean | Oils and mould release stay under the sleeve and outgas in service | Wipe with a compatible solvent and let it flash off before recovery |
| Sharp edge under the wall | A burr punctures a 0.05 mm to 0.2 mm wall during recovery | Deburr and radius every edge the sleeve crosses |
| Pulling the sleeve while hot | Wall stretches thin at the grip point and never recovers to spec | Position first, heat second, do not tug |
Thin wall changes every tolerance
The medical and semiconductor grades run walls down to 0.05 mm and recovered IDs below a millimetre. At that section the sleeve behaves like a film, not a tube. Bending it around a radius it was not sized for creases the wall, and a crease is a dielectric weak point. State the minimum bend radius with the drawing so the tube is not stressed while it is still hot.
What to check on a recovered sleeve
- Full recovery against the substrate profile, with no loose pocket and no bridging over a shoulder.
- Even wall around the circumference. Pinch the tube and roll it: a wall that varies by eye is a wall that varies in dielectric strength.
- Square ends with no lifted film, and the sleeve clear of any sharp transition it was not sized for.
- No gloss band or discoloration, which mark the spots where the heat source dwelt.
- Documented recovery profile, so the next batch in the oven repeats the same result.
The material decision itself sits on a different question, and we keep it on a separate page: which of the three grades suits the chemical and temperature duty. Once that is fixed, the process above is what decides whether the part survives.
Seen in context: the fluoropolymer heat shrink tubing route brings together every part that goes into this job.
Products for this job
These are the fluoropolymer grades we run. Every quote states the recovered ID and the wall, not just a supplied size. Send the part and the equipment you recover with, and we will confirm the size and the profile against them.
Related reading
- Fluoropolymer Heat Shrink Temperature: PTFE vs FEP vs PFA
- PFA vs PTFE Heat Shrink: High-Purity Application Guide
- PTFE vs Silicone Heat Shrink at 260 C
- Heat Shrink Tubing Size Chart
Common questions
What temperature recovers PTFE heat shrink tubing?
PTFE needs the highest recovery heat of the three fluoropolymers and will not seat with a normal hand heat gun. Confirm the exact profile with the tube supplier and check that adjacent parts tolerate it. FEP recovers at a lower temperature and PFA sits between the two.
Can I use a standard heat gun on fluoropolymer heat shrink?
On an open assembly, yes, provided the gun reaches the recovery window and you keep the nozzle moving around the circumference. For a thin wall, a fitting inside a housing, or a batch of parts, a convection oven gives a more even result and fewer rejects.
Should I size by expanded or recovered diameter?
Recovered. Order by recovered ID and wall thickness. A tube specified only by its supplied expanded size recovers to a final ID that has nothing to do with the part you are covering, and there is no second attempt.
Why did my sleeve go glossy on one side?
The heat source dwelt there. A gloss band marks wall thinning, and the thin section is where the part will crack or fail dielectrically. Recover in one direction at a steady speed, heating the whole circumference as you advance.
How thin a wall can be recovered reliably?
Ultra-thin walls around 0.05 mm are available for medical and semiconductor work, and recovered IDs in the sub-millimetre range are routine on those grades. Thin sections need oven recovery and a stated minimum bend radius so the wall is not stressed while hot.
Does a burr on the part matter under a fluoropolymer sleeve?
Yes, and more than with polyolefin. A 0.05 mm to 0.2 mm wall punctures on a burr during recovery. Deburr and radius every edge the sleeve crosses, and radius the ends of the part too.
Can I rework a badly recovered sleeve?
Rarely. Fluoropolymers do not return to the expanded size, and heating again thins the wall further. Cut it off, clean the substrate properly, and fit a new sleeve sized by recovered ID.
Where do I send the recovery profile question?
Send the grade, the recovered ID and wall, the substrate and the environment. WELLELE supplies PTFE, FEP and PFA fluoropolymer heat shrink tubing with wall down to about 0.05 mm and clean-cut ends for medical and semiconductor use, and we confirm the recovery profile with the drawing.
Specifying this part?
Send the drawing for a manufacturability review.