Good day, dear guests, subscribers and those who started repairs in the winter!
This post was born because I threw out three cylinders of not the cheapest foam. Of the 60 liters declared on the label, I squeezed out no more than 15 liters from each container. and was one of those people who do not read the instructions before using))).
Before writing the article, I studied from and to the instructions for use and delved into the topic, in fact, that's why I'm sharing this publication with you ...
1. Firstly, it is important to purchase formulations intended for use at low temperatures, which is always noted by the manufacturer on the back of the bottle and the "snowflake" icon.
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2. The second thing that is worth paying attention to: at different temperature conditions, we will receive completely different volumes of foam at the output when using the same cylinder - and this is a fact. Consider this circumstance when purchasing the number of cylinders.
At subzero temperatures, the chemical reaction of the components slows down, the material becomes more viscous and the pressure in the cells becomes much lower. Under these conditions, the crystallization process slows down and the foam volume decreases. Due to the reduced pressure, the foam is less susceptible to expansion, but the structure is denser.
If at +23 ° С the foam yield according to the manufacturer's label is approximately 45 liters, then at 0 ° С and –10 ° С it will be 35 and 25 liters. respectively (half as much).
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3. Thirdly, during the crystallization of the composition of the polyurethane foam, there is an intense absorption of moisture, and in the winter, at switched on radiators - humidity is always lower, and for its normal maturation - the air must be humidified with any available way.
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4. The fourth, no less important rule is that storing a cylinder at a low temperature is fraught with a loss of volume when the composition comes out, which I did as well. Due to the increased viscosity, as noted earlier, the foam sticks to the walls of the vessel, and if it also lies horizontally position - then the risk of sticking of the composition on the cylinder valve is likely and subsequently the volume of foam output will be much lower from declared.
Therefore, before use, the cylinder is kept at a temperature of more than +15 ° С... +20 ° С for at least 12 hours, after which it is necessary to shake it well for 1-3 minutes.
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5. Immediately before use, be sure to dust and moisten the surface. The optimum surface temperature when applying the foam is specified on the label, but usually is not lower than + 10 ° C.
Attention! It is forbidden to heat the cylinder with heat guns and other heaters to t more than +50 ° С. Firstly, non-uniform strong heating accelerates the crystallization process of the prepolymer, and this is fraught with the formation local clots inside the balloon and secondly, the risk of injury is very high, since the foam in the balloon is under pressure!
Thanks for attention! Hope it helped! Successful renovation and construction!
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