Application of mounting foam and sealants in construction
In this publication, we will consider what constituent foams and sealants are, their composition, properties and characteristics, which should be considered when purchasing.
Building mounting foam
In general, the mounting foam is a sealant based on polyurethane and packaged in aerosol packaging. The cylinder contains a liquid prepolymer with functional additives dissolved in liquefied gas. It is precisely compressed gas that allows the foam to actively exit the cylinder. In solid form, the substance is polyurethane foam. As a displacing agent, propylene and propellant are commonly used.
The mounting foam is polymerized, frozen under the influence of moisture, which is in the air and on the surface. That is, the air in the room, where you apply foam, the longer it will be necessary to wait for solidification.
Main features of mounting foam
As with any building material, the mounting foam has a number of characteristics, which depends on the quality of the product. All the highlights will necessarily be indicated on the label. So, what is worth paying attention to when buying:
The degree of primary expansion is an indicator of how many times the volume of foam will increase at the outlet of the cylinder when in contact with air.
The degree of secondary expansion is an indicator of an increase in material volume after the expiration of the complete crystallization period.
Foam density. Exactly it affects the exponent. In household foam, this indicator is lower than in the professional. To obtain a very tight seam it is necessary to purchase foam with a low secondary expansion rate.
Shrinkage is indicated as a percentage and implies a reduction in the final volume of the composition to the specified value.
Volume of foam output. On each balloon you can see the numbers – “50”, “60”, “70”. What do they mean? This is the number of liters of foam that comes out of the cylinder. But the specified quantity can only be obtained under condition of operation under the correct temperature regime and controlled humidity parameters. Usually the actual amount of foam will be smaller.
Adhesion to the materials – in other words, the ability of the composition to “stick” to different surfaces.
Fully fading and cropping time – given these parameters, you can have an idea of the time it takes to carry out the work, and you will realize how many hours you can plaster, grind or suture to other influences without harming it.
The weight of the balloon is a very important indicator. Note that if the cylinder shows a volume of 750 ml, then it should weigh not less than 850-920 grams. If it is easier, then the composition inside is much less than stated. This can be found with unscrupulous producers. For clarity, you can hold in the hands of balloons of different brands of the same volume. It is possible that one of them will be obviously harder. It’s worth buying.
BauGut mounting foam and sealant
Which foam is better, household or professional
It is very easy to distinguish the professional mounting foam from a professional. Just look at the balloon – if attached to it is a nozzle in the form of a thin plastic tube, then it is intended for domestic needs. Let’s look at the main differences that will help you decide and choose the right look.
The first thing that is immediately noticeable is the amount of packing. Household foam is sold in cylinders with a capacity of 300 ml and above, while a professional – from 750 ml and above.
An important indicator is the foam output from the cylinder. In the case of household spray, the entire composition can not completely blow out. Typically, some part stays inside, and you get a somewhat averaged value from the volume declared by the manufacturer. Thus, instead of the necessary one cylinder, it may take two, and this already affects the costs associated with the repair. In this plan, much more professional foam, which is blown out almost completely.
The coefficient of secondary expansion in households is very large. In the final hardening process, they can increase up to two times in volume. The same coefficient of professional foam is practically zero. Therefore, as a rule, specialists fill only 1/3 of the gap with household foam, knowing that, after hardening, it will fill the entire space without changing the geometry of the adjacent surfaces.
Indicator of household foam shrinkage is 5-7%. Professional – 0-3%.
With household foam, it’s easy to control: just tighten the tube supplied in the kit, shake well, and the foam is ready for use. Professional compositions work only with the help of a gun of considerable value. For one-time minor repairs, the purchase of professional foam is not practical: among other things, a special wash is also required to clean the gun from foam residues.
Professional foam can be used partially. But, keep it at the same time necessary with a pistol dressed on the balloon. In this case, the foam inside does not cure and is suitable for further application.