Heat Gun
Settings for
Heat Shrink

Set the gun to 300–400°C (572–752°F) of air temperature. Around 300°C suits small tubes (3/32" to 3/16"), 350°C medium tubes (1/4" to 1/2"), and 400°C large tubes (5/8" and up). The air is far hotter than the tubing needs to be, so keep the gun moving — the tube itself only has to reach 100°C to shrink and 120°C for a dual wall liner to flow.

HELIXAL tubing starts shrinking at 100°C (212°F). On 3:1 dual wall tubing the adhesive liner melts and flows at 120°C (248°F) — a little hotter than the shrink point, which is why you keep heating after the tube looks shrunk until adhesive shows at both ends. Once installed it is rated for continuous service up to 125°C.

Start about 4–6 in (10–15 cm) away with a normal corded gun, and 3–4 in (8–10 cm) for small tubes. Move closer only if the tube is slow to start shrinking. Cordless guns move less air, so hold them a little closer. If the surface turns glossy or brown you are too close or too slow.

For dual wall (adhesive-lined) tubing, yes. The outer wall shrinks at 100°C, but the seal only forms when the whole liner reaches 120°C and flows out to both ends — and only a heat gun brings the full length of the tube there evenly. For a small single-wall repair you can get by without one, but treat the result as temporary.

In order of preference: a butane mini heat gun or micro torch on its hot-air tip (good for small tubes, too small for large ones); a propane torch with the flame kept well clear and moving fast (large cable outdoors only); a lighter (emergency only, small single-wall tubing, temporary). A hair dryer will not work. None of these heats evenly enough to seal dual wall tubing reliably — redo those joints with a heat gun.

With a heat gun at 300–400°C, held a few inches away and kept moving. Start in the middle of the tube and work out to each end so air is pushed out rather than trapped, and turn the work (or move the gun around it) so every side shrinks evenly. On dual wall tubing keep going after it looks shrunk, until a small bead of adhesive shows at both ends. The full step-by-step install is in our How to Use Heat Shrink Tubing guide.

Any gun with variable temperature, around 1500W, and a reflector nozzle. Variable temperature matters most — it lets you run small tubes cooler and large dual wall tubes hotter. A basic two-setting gun also works well; cordless guns are fine for small and medium tubes but slow on large dual wall. We do not rank brands we have not tested.

Only as an emergency, temporary fix on small single-wall tubing. A flame puts too much heat in one spot: it soots and scorches the outer wall, and a scorched jacket cracks at the next heat cycle. Do not use a lighter on dual wall tubing — it cannot bring the whole tube evenly to the 120°C the adhesive needs, so the joint will look sealed and not be.

No. A hair dryer cannot hold the tubing at the 100°C it needs to shrink, let alone the 120°C a dual wall liner needs to seal. At best it softens the outer wall.

It is possible but risky, and only worth it on large cable outdoors with no other option. Keep the flame tip well clear of the tube, sweep fast, and stop at the first sign of browning. A heat gun gives even heat and is the better tool every time.

Yes for small and medium tubes. Cordless guns move less air than corded ones, so they take a little longer and work best held closer. On large dual wall tubing they are slow to get the adhesive flowing — a corded gun is the better choice there.

Look for a small bead of adhesive at both ends of the tube. The outer wall shrinks first, at 100°C, but the seal only forms when the liner reaches 120°C and flows out to the ends. No bead means the adhesive has not flowed — heat it a little longer, working from the middle outwards.