Introduction

Shrink wrap is different from other coverings like tarpaulin or stretch wrap because it creates a 'drum tight', moulded fit over the object it covers. Because it is tight, this means it cannot flap or chafe and therefore it tends to be very durable.  The shrinking process is initiated by blowing hot air over the surface of the shrink wrap until it has shrunk to the required tightness.

Lightweight shrink wrap plastic is commonly used for the packaging of foods or consumer goods which after being wrapped pass through a computer controlled hot air tunnel on a conveyor belt. However, where much thicker industrial grade shrink wraps are used to packaging pallets or large industrial objects, then a shrink wrap tunnel is clearly impracticable so a hand held portable shrink wrap heat gun is used. These hand held guns are powerful tools, normally powered by propane gas or 3-phase electric supply and are not to be confused with the widely available domestic hot air guns, commonly used for stripping paint etc.

Because the correct choice of shrink wrap heat gun, and it's correct use, is fundamental to the success of the finished job, this guide will compare of some of the most popular models available. The guide concentrates on the heat guns most commonly used in Europe. It will look at costs, typical operation procedures, the benefits of electric and gas heat guns and also examine accessories such as heat gun extensions.

Note:
Although shrink wrap heat guns are easy to use devices, in daily use by many thousands of companies, you should always ensure that staff have been fully trained, that the manufacturers instructions for each model of heat gun are followed and that all risks have been assessed. In addition to the guidance issued by the individual manufacturers of shrink wrap guns there is further general advice on the correct and safe use of heat guns and the correct use and storage of propane gas. Reference to any brand of heat gun in this article should not be considered an endorsement of that particularly brand by the author and you should always make your own checks to ensure that any shrink wrap heat tool purchased and used is 'fit for purpose'.

Shrink wrap gun operation

Most shrink wrap heat guns are powered by propane gas and work in a similar way. They are hand held devices with a handle / trigger, and are connected via a 8-10m flexible rubber hose to a propane gas bottle. The propane gas bottle is normally moved around the work area on a gas cylinder trolley for safety. Where the operator may have to move around the object it will make the shrink wrap job quicker and less tiring. When the trigger is partly depressed, gas is drawn along the barrel of the gun where it is mixed with air. As the trigger is fully depressed an electrode generates a spark which ignites the gas and air mixture in the burner to create a flame. The burner is normally protected by some kind of cowl to prevent accidental burns. The trigger acts as a safety device – when it is released, or if the gun was accidentally dropped, the flow of gas is cut off and the flame extinguished.

The heat gun can first appear quite a daunting piece of equipment to use. When the trigger is depressed, and the gas ignited, the flame is quite visible and burns with some ferocity and can be quite noisy, (almost like the noise of a burner in a hot air balloon). However, it is not the flame of the heat gun that is used to shrink the plastic covering but the hot air that the flame generates. Different guns will produce a slightly different pattern of hot air, but normally shrink a roughly oval area of around 30-40cm in diameter. The temperature required to shrink plastic films will differ between types of film and manufacturers but shrink wrap normally begins to shrink at around 100-140 Deg C.

Gas or electric powered heat guns?

In some environments a gas powered shrink wrap heat gun may not be appropriate. Electric heat guns are commonly used for paint stripping or for shrinking the plastic insulation around cabling, however for shrink wrapping large objects the use of these 'domestic grade' tools is clearly impracticable because of the low heat output and the tiny area of heat produced.

Larger 'industrial grade' electric shrink wrap are available but they are heavier, more expensive and cannot match the heat output of a gas gun. What this means is that the hot air must be directed at any point of the film for much longer which can lead to more heat being transferred through the shrink wrap to the object below.  Gas powered guns are by far the most popular choice and it is gas shrink wrap heat guns that we will concentrate on for the rest of this article.

Using a propane gas powered heat gun to shrink plastic film or wrap is very much like spray painting with hot air. Rather, than the heat being held in a single place on the shrink wrap it is kept constantly moving, normally from the bottom to the top of an object, so that the ripples and creases are 'chased out' and the shrink wrap is taught and tight. Because the gun is kept moving and not held in a single place for more than a couple of seconds, little heat is transferred through the wrap. The motto is 'hit it hard and move on!'

Heat gun extensions

When using shrink wrap to protect particularly large objects, a shrink wrap heat gun extension is often used. Using a heat gun extension allows the operator to shrink tall objects without the use of  access equipment such as a step ladder or platform. Generally speaking when large objects are being wrapped, by the time the

Most common European shrink wrapping guns

The Ripack shrink wrap heat guns are made in France. Distinguished by their bright orange casing, these guns are stocked by many packaging companies. Marketed as the most powerful shrink wrap heat gun on the market, heat output is listed as 187,000 BTU's / 55Kw. Uniquely it has an aluminium body and weighs around 1.2Kg. Another feature of the Ripack heat gun is the 'unique patented' cold nozzle. Available for the Ripack range of shrink wrap heat guns is a wide range of extensions from just 0.57m (1'10”) to 2.03m (6'8”). Expect to pay around £450-£500 for this shrink wrap gun.

The Shrinkfast range of shrink wrap guns are manufactured in the USA but are also available in Europe. The '998' model weighs around 1Kg has a adjustable power output from 134,000 to 212,000 BTU. Like the Ripack gun, extensions are available up to around 6'. Again, this gun is supplied in a case, with a regulator and approximately 8m of hose. Expect to pay around £450-£500.

The Shrink Ltd. Range of guns are perhaps least well known but well worth considering. Weighing only 1 Kg, this gun is of very simple construction having only 10 parts! Feedback from companies using this heat gun is that reliability is excellent. This gun has been made in the UK for many years and to a tried and tested design. Heat output is a more than adequate 100,000 BTU's, and like most other shrink wrap heat guns it is supplied with a regulator and 8m of hose. However, one of the main attractions of this gun is that it is significantly cheaper than the others – expect to pay around £350 for the shrink wrap heat gun, regulator and 8m hose.


Gas consumption for a typical shrink wrap heat gun operating at 100,000 BTU will be around 2Kg/hour if used continously. (Typical gas cylinder used are 13 or 19kg)

Note - If you are going to buy a shrink wrap heat gun that has not been manufactured in your country, then you may have to purchase a different regulator from that supplied with the gun. Always check before purchasing.

Some common shrink wrap heat gun faults and probable causes

1.Gun not firing: Gas supply not on. Damaged electrode. Gas valve adjustment screw not operating plunger. Defective spark generator.
2.Gas has yellow flame: Gas pressure too low. Blocked jet. Gas leak in body. Blocked valve. Iced supply.
3.Large flame: Too high pressure. Too large jet. Blocked or damaged mixer.

For further information or advice on buying a gas heat gun, please click here Tufcoat Shrink Wrapping Supplies

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