The greatest and most unique feature of PMMA, unavailable in quartz glass, is the ability to thermoform it freely.
To obtain the planned panel shape, a negative mold, known as a plug, is made. A panel of calculated thickness is fixed to this element and placed in a cold oven.
According to calculated parameters, the oven heats up to a temperature dependent on panel thickness. A very slow process follows, in which the material settles onto the plug, and the final stage is gradual cooling. Depending on panel thickness, this process can take several or even more than ten days and is controlled with an accuracy of 0.5 degrees C. This is how our pool windows, tunnels, aquariums and other tanks of non-standard form slowly take shape. In addition to its visual appeal, thermoforming has major importance in selecting PMMA panel thickness, which brings specific savings.
For example, a cylinder measuring 100 x 200 cm can be made from material 2 cm thick; for a rectangular tank, the minimum would be 6 cm. We produce cylinders from tubes up to a diameter of 100 cm; above 100 cm, the cylinder is made from two thermoformed halves.
The bonding is essentially invisible and resembles a 2 mm optical flaw, visible only from certain angles. Properly performed thermoforming does not change the PMMA structure or its surface in any way.
Determining the time parameters of thermoforming requires extensive practice and knowledge. Frequently encountered force thermoforming produces a wavy external structure and makes it necessary to remove a deep layer of material, carry out three-stage sanding and final polishing.
PMMA renovation is technologically difficult with deep damage and relatively simple with superficial scratches. It still requires suitable tools and specialist chemical agents.
Ten uses of acrylic in pool technology.
