Anyone who has to deal with electrical connections in household, hobby, model making, or model railroad knows that electrical contacts are the “most reliable” source of error. To prevent future mistakes, a heat shrink tubing offers an ideal and also very cost-effective way to professionally secure electrical connections. You will find the necessary know-how about heat shrink tubing here.
With a shrink tube, you avoid dangerous short circuits and secure connections.
Just as important as making electrical contacts is to avoid unwanted communications in all electrical line operations. Therefore, you should use heat-shrink tubing to secure any contact or solder joints that may cause shorts under adverse conditions. The coating and connection of electrical contact points using heat shrink tubing application offer you in practice these typical advantages:
- Electrical insulation, such as open solder joints and cable insulation of all kinds
- Repair of damaged insulation on cables
- Mechanical improvement, especially for shrink tubing with internal hot melt adhesive (internal adhesive)
- Kink protection, moisture protection, weather protection
- Air seal and thus protection against corrosion
- Color coding of different conductors
- Attachment of labels and warnings
This is how the heat shrink tube fits your application.
Shrink tubing consists of plastic polyolefin (self-extinguishing). Polyolefin has excellent tensile properties, high stability, and puncture resistance. Its other characteristic feature is shallow (controllable) shrinkage strength. Therefore, it is not only used as a tube but also in foil form, for example, to assemble and insulate battery packs.
The heat shrink tube must fit precisely to the cable diameter to be insulated. Heat shrink tubing is described in the trade as having two numbers, the first of which indicates the circumference as supplied and the second the maximum shrunk circumference of the tube.
This is usually about half: So, a cable shrinks under hot air by a maximum of 50% in diameter. One then speaks of a shrinkage rate (shrinkage ratio) of 2: 1. However, the shrinkage range – the maximum size change during shrinking – strongly depends on the plastic used, so that the shrinkage ratio can be up to 6: 1.
The right shrinkage ratio is crucial.
The recommendation thus depends on the cable thickness used. In general, the thinner the cable, the smaller the shrink tube. Generally, manufacturers recommend a 4: 5 ratio between the diameter of the object to be insulated and the shrink tubing for best results.
As a result, you can find the right diameter for the heat shrink tubing to insulate a connection by using heat shrink tubing about one-fifth of the width of the outside diameter of the cable or insulation. For example, if it is a 2mm diameter cable, including insulation, you should use 2.5mm heat shrink tubing.
How To Shrink Properly: Processing Instructions for Heat Shrink Tubing
- The temperature required for the shrinkage process is approx. + 120 to + 200 ° C. A hairdryer is therefore unsuitable; he does not get hot enough.
- The ideal is the use of a hot air gun. Follow the manufacturer’s instructions for temperature and speed settings of the hot air gun.
- Even without a hot air gun, you can shrink: Skilled model makers often use the stem of a heated soldering iron or a pure gas lighter. However, the tip of the flame must not touch the shrink tubing but only carefully be passed at a suitable distance. If necessary, a light bulb with correspondingly high thermal power dissipation also works.
- Do not fry on any part of the heat shrink tubing when shrinking. Run the heat source, similar to a paintbrush, past the heat shrink tubing. Due to the heat, the tube then shrinks well playable in diameter and fits tightly around the cable. This completes the shrinking process. Under no circumstances should the heat shrink tubing start brown or black.
- Particularly suitable for mechanically loaded connections is special shrink tubing, which is coated on the inside with hot melt adhesive (heat shrink tubing with hot glue). With the glue on the inner wall, it is possible in some applications, for — B. to connect cables to the terminals of an LED without having to solder at all. The hot melt adhesive produces a powerful bond upon heating after cooling.
Special shrink tubing for hobby electrics, model making and model railroading
Shrink tubing is available in assortments in the hardware store and electronics trade. Ideal for hobby and model making is the heat shrink tubing from the Modax range, which is sold through model-making shops. The advantage of the Modax heat shrink tubing: They are easier to process than standard heat shrink tubing because they are a little more flexible, and the shrinkage temperature is slightly lower.
This is ideal for modeling purposes, but the price is slightly higher than for shrink tubing from a standard range. Caution Trap when buying: Pay attention to the express term “heat shrink tube,” as assortments of insulating hoses look confusingly similar.