Még több cikk a témában

One third of the cooling load in summer is caused by heat flowing through windows. Although the external unit of the air conditioning apparatus can be found on more and more buildings, the air conditioning apparatus installed inside is not a solution for everyone. In some cases, it is difficult to install due to the layout of the apartment, while others rather prefer natural shading. Anyhow, there is an efficient way to prevent the apartment from becoming a sauna in the summer heat waves without the need to drill walls and place wires.

Heat reflective films on windows

As its name suggests, we are talking about self-adhesive heat reflective window films that block sunlight and prevent the accumulation of heat caused by that. The heat reflective window film blocks 45-86% of the heat of sunlight before it enters the apartment.

It is all the Sun’s and the glass surfaces’ fault. Glass admits the light’s range of 280 – 2500 nanometer coming from the Sun due to its structure. This means part of the UV-radiation (UVA and UVB), the whole range of visible light and a proportion of infrared-radiation.

Any type of film for vehicles with a simple color can block the range of visible light and it even provides energy protection, but their filtering in the range of infrared light is very low, around 12%. Why is this fact a problem? Infrared radiation penetrates the skin layer deeper than visible skin, therefore it stimulates receptors more, thus it causes a significantly more intensive heating comfort. So, it can be a good solution to reduce the heating comfort coming from the Sun to a minimum by powerfully filtering infrared radiation. For this reason, we call heat reflective films those products that filter also in the range of infrared.

Heat reflective films on windows contain a group of products that can be classified according to various production processes. The first level of heat reflective window films means colored films with an aluminum metallized structure, which is followed by fully metallized products, less reflecting nickel-chromium films, ceramic heat reflective window films based on titanium-nitrate – these have an excellent heat protection and their infrared filtering is around 80-60%. Finally, there are so-called infrared absorber films as well. The technology was developed in Japan and it is based on a special particle that can absorb infrared radiation.

3M’s product range even offers a heat reflective window film that is of premium quality and is prepared with several layers and by metal-free nanotechnology.

A transparent or colored heat reflective film can be a smart decision because it cools in summer and warms in winter, so it can hold heat inside during the cold period. There is no need to be afraid heat reflective window films will make the apartment darker because they admit sun and they only withstand heat.

The range of heat reflective window films currently available in Hungary is quite wide: we can choose types that provide 40-60-80% of protection against the heat.

Areas of use of heat reflective films

Needless to say, that the primary area of use of this product includes glass surfaces of houses and apartments, so we have to think of windows first. Blinding light is not only a health risk for those being inside, but it can also damage and fade furniture and equipment. The sunlight breaking into the living space can be well controlled with an appropriate film.

In case of window insulating films, it is possible to choose an outdoor type, in which case the film is applied onto the outside of the window, but this is not an optimal solution: outdoor window films have a shorter lifespan than if it was applied indoor, so it needs to be frequently replaced. For this reason, it is generally recommended to install window films onto the inner side of the glass surface: this way, the lifespan of the heat protection film is longer, and it is easier to ensure a dust-free environment during installation.

However, glass plays an important role not only in our homes but also in our vehicles. Driving in bright sunlight can be joyful on the one hand, but on the other hand it can also be annoying: the beam of light coming from the front can limit vision and can blind the driver, especially during a longer drive. With the help of a colored, tinted film, this effect can be reduced, it allows a better utilization to the air conditioning system, and, in the long run, the temperature of the vehicle’s interior space can remain comfortable.

It is true also in this case that by filtering UV-rays, skin damage can be better prevented, and the internal color of the vehicle will not fade either. For example, FX car window films can reflect 46% of the full solar energy penetrating through the car’s windows, they have an anti-scratch protective layer and they are available in various shades. Everyone can find the film that is the most suitable for them.

Another aspect not to be underestimated is that the film does not produce a significant amount of waste, so in case of replacing the window, we do not have to expect an environmental impact caused by the disposal of windows.

It is now officially spring! This season is characterized not only by the awakening of nature but also by getting busy with garden- and house works. The increasingly warming temperature this time tempts many to finally start or finish their long-delayed home improvement tasks. One of these activities usually revolves around sanding – that is often coupled with a lot of noise. In this entry, we will briefly review what is to be known of electric sanding machines for working in the hand.

Vibrating or orbital sanding machines

According to their names, engines built in such types of sanding machines are driven in a vibrating, oscillating, circular movement. The less is the diameter of this circle is, the “finer” the sanding will be. Their sanding surface is usually of rectangular shape, which is covered by sized abrasive cloth well fitted by a spring mechanism or by Velcro. This is a sandpaper-like surface that we fit to size or we buy in specialized stores and in the appropriate sections of supermarkets in the desired size. Orbital sanding machines are suitable to fine sand surfaces larger than average, and in this case, we do not have to remove the whole layer of paint from the surface to be sanded.

A special type of orbital sanding machines is delta sander, which was named after its distinctive triangular shape. This is to be used mainly to sand spots that are difficult to reach with other types of sanding machine, because it is possible to treat more hidden surfaces by using longer and narrower abrasive paper. They can also be used to sand gaps and holes, but they can handle shutters and blinds as well.

We are still in the category of orbital sanding machines when we mention hand sanding machine. The working surface of this small-sized tool that can be easily held in the hand is special because – due to its circular shape – it even rotates around its axis in addition to vibrating. As a result of this, a particularly good result can be achieved with it, for example on curved surfaces.

Belt sanders

As opposed to orbital sanding machines, sanding in this case is conducted by a belt stretched around two rotating cylinders. Sanding in belt sanders are done by a plastic pulley driven with a high speed, and we usually use it for metalworking. Their unique feature is the ability to quickly remove materials, especially when the aim is to fully remove the layer of paint or varnish from large, long surfaces. Belt sanders have a sanding frame that allows to conduct accurate surface sanding.

There are so-called eccentric sanding machines that make it possible to sand really large surfaces extremely fine, and multifunctional machines are also available, although these are mostly devices that need be mounted on tables. Eccentric sanding machines are also special from the aspect that they are excellent also for curved surfaces and they can be used to polish straight or convex surfaces made from various materials – wood, metal or plastic.

Accessories of sanding machines

No sanding machine can be used in itself! As we have seen, we need abrasives, sanding sheets, but brushes, abrasive tools, discs, wheels or polishing and buffing pads can also be found in the range of related products.

Since the invention of the first, still natural materials, adhesive technology has evolved much. However, the aim has not changed: two materials need to be stuck together. In this article, we will have a brief summary of the types of adhesive.

Basic classification of adhesives

Usually adhesives are liquid materials that need to be made suitable for the purpose of application before using them, that is to make them liquid as surfaces can be moistened only this way. Solidification takes places when solvents evaporate or during solidification processes. These are mainly the characteristics of one-component adhesives.

Based on their binding methods, adhesives can be divided into two categories. One group is comprised of adhesives binding without chemical reactions that do not actually bind, only moisten. These are cold-binding, permanently adhesive materials, and some of these create binding by drying, when solvents evaporate. Hot melt adhesives do not stick at room temperature, they do not moisten, so the adhesive needs to be melted first to create binding, the melt needs to be applied to the surface, and usually we need to apply clamping force. Bonding is created by the adhesive solidified in the binding.

The other group includes adhesives binding with a chemical reaction that can be further divided into two more categories based on the nature of reaction: polymerization and polycondensation adhesives. In the first case, the new binder is created by the continuous combination of the components, while in the second case, due to the pressure of the condensation by-product, the application of clamping pressure is always required in adhesive technology.

We started from here: adhesives of natural origin

This includes materials of flora and fauna. With the minor or major chemical transformation or physical modification of plant materials and of the sap of certain trees or materials extracted from fruits, vegetables and crops, adhesive materials can be produced. One of such most important materials is cellulose, the building material of plant cell wall. Starch, produced by biosynthesis in plants, is also very important. The paste, extracted from starch by wet cooking, can be used as glue.

From adhesives of animal origin, it is worth mentioning glues, like casein glue, which is one of the milk’s proteins. It is distributed in a powder form, which you can use by mixing with water, and it solidifies by evaporating water. One of the oldest adhesives known and used is animal glue, which is distributed in the forms of powder, granule, bead and slab. Its advantage is that during cooling, it instantly provides adequate initial adhesive strength.

Adhesives of mineral origin

Adhesives in this category can be organic, such as bitumen and inorganic, such as cement. It is good to know that despite their limited scope of use, they are of great importance, they are irreplaceable.

Adhesives made from glass melt were used for heat- and fire-resistant metal bonds. Ceramic adhesives can be used to create heat-resistant bonds more generally than glass. Phosphate cements are also of mineral origin and they are the basic materials of dental fillings, or lead oxides used to repair ceramic pipes, valves, stoneware goods, or hydraulic cements, such as gypsums. This latter – together with bitumen – is considered as the most important binder of architecture.

What about synthetic adhesives?

Synthetic adhesives produced by modern chemical industry started to replace traditional ones from the middle of the 20th century. Epoxy started its “career” in the 1950s, which was successful primarily due to its ease of use, excellent strength quality, and 100% content of dry matter.

There are a lot of types of synthetic adhesive. For example, the most important areas of use of polyamides are adhesives for upper making or mounting on shoe trees in the shoe industry, adhesives of metal-to-metal bonds in the automotive industry, structural wood adhesives in the timber-processing industry, but tools made from it also have an important role in the production of components for major appliances.

Polyurethanes are one-component solutions that are suitable to glue textiles, leather, wood and paper. Epoxy resins are usually comprised of two components that need to be mixed before use in the proportion specified by the manufacturer, which results in polymerization, that is the solidification of the adhesive. They can be used to glue various materials, such as metals, ceramics, porcelain or wood. (Two-component adhesives often have the fancy name of ‘power’, referring to the strong bond that can be created with these products.)

The solution of polymerization adhesives is primarily used to glue objects made from the same materials. Solvent polyacrylate adhesives can be used to glue some types of plastic – like polystyrene, PVC, polyethylene – wood, paper, leather and textile. Finally, we should not forget about polyacrylates: the best known of these are cyanoacrylates, which we know as superglue in everyday life, and their thicker gel type can be used also to fix glued surfaces. Among them, we can also find types created to firmly fix specific types of materials.

Of course, the world of adhesives has become enormous since the first materials. Today, in relation to this, we do not talk about adhesives only but also about a wide range of products that aid gluing: such as accelerators, adhesive applicators or sealants and filling materials. A separate category is also comprised of various adhesive tapes that make operations much more comfortable than it was for our ancestors using animal glue. In addition, it is possible to buy adhesives with good bond strength for almost all types of materials, and also there are several types of universal adhesives available in specialized stores.