To seal joints and joints, performing moisture and heat insulation work, polyurethane foam is widely used in the construction industry. The material easily adheres to different surfaces, has a long service life and high strength. Polyurethane sealant is easy to apply using a construction gun. To complete the finishing treatment of foamed areas, you need to know how long it takes the polyurethane foam to dry. This parameter depends on several factors - the quality of the sealant, conditions of use, type of material.
Basic properties and characteristics of polyurethane foam
The vast majority of such compositions are distinguished by the following parameters:
- B3 – ability to resist fire. This figure is considered not very high.
- When applied, the foam may fill empty areas. This ability is called “primary expansion.”
- Under direct exposure to sunlight, the polyurethane foam begins to deteriorate. Therefore, other substances are applied to the layer of material for additional protection.
- With glass, plastic and metal, wood, the composition provides good adhesion. The same cannot be said about silicone and polyethylene and other similar surfaces.
- General processing of such materials takes up to 45-60 minutes.
- Operating temperature – from -40 to +90°С.
- 0.3% hygroscopicity.
- 90/40 kPa – shear strength of a flat surface.
- 13/17% – probability of rupture.
- 0.036 W – heat conductivity. This can also affect how long it takes for polyurethane foams to harden.
The foam is evenly distributed on the surface and fills voids, but only if it is used correctly. It is known for its low shrinkage rate. Able to resist the external environment. But many people ask how long it takes for polyurethane foam to dry when installing a door.
The main factors influencing the hardening of polyurethane foam
Let's figure out what environmental factors influence the drying speed of polyurethane foam.
Recommended Application Temperature
One of the most important points for the drying time of polyurethane foam is the temperature of the air flow around it. The process is accelerated if it takes place indoors with heating. On the contrary, it takes less time outside in the cold.
Ambient humidity
Humidity may cause drying to accelerate. If there is a lot of steam, everything goes faster. A humid climate near the sea has a similar effect. This does not happen in dry areas. How long the polyurethane foam dries when installing a window also depends on several factors.
Thickness of applied layer
One of them is the thickness of the layer. At ideal humidity and temperature, it takes about 3 hours for the 50 mm mounting layer to dry. After 12 hours, polymerization occurs in full. After at least a day, you can process the thickest seams.
Surface type
Surface type can also play a role. An increase in the hardening time of polyurethane foam occurs in the presence of altitude differences, flaws and irregularities.
Material application process
You should also work with plaster according to the instructions:
- Prepare the construction mixture: dilute the dry material with water in accordance with the proportions provided by the manufacturer.
- The plaster should be laid on the foam sequentially, forming 2-3 layers. There should be a break of 2-3 hours between them. When working with gypsum plaster, 2 hours is enough. Cement mixtures take longer to set - you should wait up to 3 hours. The recommended layer thickness is 5 mm.
- Sometimes it is necessary to strengthen the coating. To do this, use a mesh for internal use. It is secured with plaster when applying the first layer.
To ensure that the foam is protected as reliably as possible, the seam is covered with a building mixture, extending 2 mm onto the wall on each side. The coating is leveled with a trowel when the construction mixture dries. Then it is recommended to go over the top with fine-grit sandpaper (after 2-4 days).
Average time for initial and complete hardening of construction foam
Under normal conditions, the first excess material can be removed after just three hours. After this you can start plastering. The average polymerization time for polyurethane foam is 12 hours.
In cold or too dry rooms, the process is delayed indefinitely. In this case, all you have to do is wait until the end; it is not recommended to rush. Manufacturers will indicate how long Macroflex foam takes to dry on the packaging.
Inside a heated room
Ideal conditions are created with the following indicators:
- 60-75% relative humidity.
- Temperature from +20°C.
The average hardening time for construction foam inside a heated room will be a maximum of 4-5 hours
Outdoors depending on time and region
Depending on the temperature conditions of use, several types of polyurethane foam are produced.
- All-season. From -10 to +35°С. Optimal conditions of use are from +10°C to zero.
- Winter. Relevant in frosts down to -18°C.
- Summer. For polyurethane foam hardening temperatures not lower than +5°C.
When using a suitable composition, the general conditions discussed above remain the same. That is, the process takes no more than a few hours, and there are no problems or delays. This is the answer to the question of how long it takes for polyurethane foam to dry in apartments.
Expansion coefficient is the main parameter
The value of this building material largely depends on its ability to expand many times over. Household foam can expand up to 60% of its original volume, professional compositions have a much higher coefficient - up to 300%. Moreover, the same foam can expand in completely different ways under different conditions. The prepolymer is influenced by temperature, air humidity, type of application, and the rate of foam release from the container. And different masters in the same room may have different results. On the packaging, manufacturers indicate the maximum volume of polymer yield, but you should not strictly rely on it.
Expansion of the prepolymer during the process of exiting the balloon and solidification is divided into two types: primary and secondary. The primary expansion is called immediately after leaving the container, the secondary lasts until the polymer conversion process is completed. Secondary expansion for high-quality materials reaches 30%, which cannot be ignored when using them. Usually it is enough to fill the gap one-third so that it is eventually completely filled with polyurethane foam.
In addition to expansion, polyurethane foam can also shrink, although for high-quality products this shrinkage is rarely 5%. If you observe large shrinkage, alas, you have come across a very low-quality polyurethane. In this case, even a mass rupture may occur, which in turn will entail a lot of other problems. Each master chooses foam according to his needs. For some, large expansion is important, in such cases Makroflex, Penosil GoldGun, Moment, Makrosil are suitable; when installing windows, it is best to use Tytan - it gives optimal expansion and hardens quickly.
Are there ways to reduce the drying time of polyurethane foam?
It is recommended to create optimal conditions before work begins. But often it is almost impossible to achieve this. It is permissible to influence the humidity level. With enough liquid, adhesion increases. This is one of the options for speeding up the drying of polyurethane foam.
The foam must be laid so that about 1/3 of the joint cavity is occupied. The rest of the space will fill in on its own as the train expands.
Pistols with long barrels help you reach hard-to-reach places. They do not affect how much polyurethane foam expands.
There are other rules at work:
- It is important to provide adequate space for the release of polyurethane foam. The review should not be closed. Therefore, the tube spout is installed at an angle of 45 degrees.
- If there is a short break in work, the cylinder can be left in the gun. Then the mass will not solidify in the valves and tubes.
- The seam should be made evenly, without excess. The nose of the tube is almost completely immersed in the foamed composition.
If you need to foam the surface of the walls, make a wooden sheathing that looks like square cells. This helps keep the layers on the surface until drying is complete. How long it takes construction foams to dry has already been described earlier.
Requirements
Polyurethane foam is a material that, like any other, has a number of requirements.
These requirements include:
We draw the attention of users to the fact that the foam is very resistant to direct sunlight. For this reason, after complete hardening, the excess is cut off, and all compacted areas are treated with paint or plaster. And in order not to disturb the density of the material and to do the application sequence correctly, you need to know how much time is needed for complete hardening.
To eliminate gaps between door frames and openings, you will need only a third of the sealing compound. The material will begin to harden on the surface within half an hour after application. You may notice that a film will appear on the surface.
Final drying can be expected 8 hours after the material is applied. The fixing process occurs due to the expansion of the substance, which leaves the container and hardens.
Conventionally, this is divided into several stages:
If the material is of high quality, then at the second stage the expansion rate can reach 30%; this must be taken into account during the work process. Most often, a third of the material is spent filling the space; this is enough to fill all the cracks during expansion.
But you should also pay attention to the fact that the foam should shrink; you should not be afraid of this action, it will not cause problems. In high-quality materials, shrinkage can reach 5%, and this is not noticeable from the outside. If shrinkage does occur, and this is clearly visible from the outside, it means that the polyurethane was purchased of poor quality.
Other recommendations
With the correct consumption, it will be easier to buy the right amount of materials. 50 liters of foamed insulator mass is obtained from a standard 750 ml cylinder. 5 cm is the minimum thickness needed to seal the gaps near the door frame.
Standard cylinders should be enough for at least one and a half doorways during installation. If there are three doors, take at least two containers. They decide separately how long it takes to cut off the mounting foams.
It is necessary to handle cylinders with the utmost care. They do not allow any type of mechanical damage or excessive load. Leaving such compositions near sources of open fire or in the open sun is also prohibited.
From other tips:
- The use of respirators, goggles, and gloves is mandatory. Especially when it comes to closed spaces.
- The room must be ventilated.
- The foam stream comes from bottom to top.
- Do not wet the surface before starting work if the temperature is negative.
- If the composition ends up on adjacent surfaces, it is removed immediately, even before the hardening process begins.
Sellers and suppliers are required to provide certificates for their products so that buyers can be confident that there are no problems.
Consumption
Professional fireproof mounting foam KRAFTOOL Kraftflex Premium B1 750 ml. Stroylandia Photos
Polyurethane foam is available in cylinders of various sizes. Productivity varies depending on the volume. Cylinder with a capacity of 300 ml. gives approximately 30 liters, which is enough to install one door, 500 ml. — 40-45 ml., for installation of two windows, 750 ml. — 50-55 l. for two door frames. But it is necessary to understand that this amount of foam may not be possible, since ideal working conditions practically do not exist. Indicators also depend on the method of presenting the composition, the skill level of the performer, etc. Therefore, there are formulas for calculating consumption. For rectangular seams this is -
For triangular ones - P = 0.5 x W x D.
Obtaining more accurate calculations is facilitated by the use of online calculators, which allow you to find out the number of cylinders or material consumption in meters.
How long and under what conditions can polyurethane foam be stored in an already opened container?
The foam is stored in cylinders at temperatures from +5 to +35°C. Excessive overheating is prohibited, as is frost. If the cylinder is not removed from the device, it is recommended to use the composition a maximum of six months after purchase. Only in this case the working pressure is accurately maintained inside.
After removing the device, the mixture in the tube begins to harden. You need to immediately rinse the insides. This is also important for those who intend to understand how long polyurethane foam sets.
Sealant selection and market analysis
The use of high-quality and reliable building materials is the key to successful repairs. In order to seal cracks, holes, and seams at a professional level, a product must be selected with high performance and technical data.
In construction markets you can find a large number of different polyurethane foam. Experts recommend paying attention to the following product brands:
- "Moment Montage" . A well-known brand with well-deserved popularity, sold in all construction stores. It is characterized by a dense, uniform consistency and high adhesion to almost any material. It can be used both indoors and outdoors. The downside is secondary growth, as a result of which, with a large amount of foam used, the sealed seams can become deformed.
- "Makroflex" . One of the best brands. Can be used for work both in winter and summer. The foam has a uniform structure, adheres perfectly to any surface, and secondary growth is minimal. The disadvantages include market defects in cylinders that do not last long. Then either only gas comes out of them, or just sealant.
- "Soudal" . Not a very well-known company that produces quality products. The market offers polymer options for winter and summer work. Winter species are suitable even at 20-degree frosts. All products have good adhesion, little secondary growth, little shrinkage. Foam also reacts poorly to the sun.
- Penosil . High-quality sealant with a dense consistency. Secondary expansion is almost absent and is characterized by large exit sizes. Effective for indoor use, not suitable for outdoor use. Temperatures below minus 4 and above plus 35 will completely discredit him.
- "Titan 02" . The most famous brand of professional polyurethane foam. It has a relatively low cost, has excellent performance properties, a high degree of adhesion, and a dense consistency. Suitable for use in various conditions.
