Whatever the positive characteristics of the PVC film on MDF facades, over time it revealed one unpleasant drawback：It loses plastic properties, “turns to wood”, begins to break and crumble in places of inflection. This is especially noticeable when it is used in a place with a low air temperature. There are cases when it is impossible to unwind the roll so that a crack does not appear on the film.
The reasons for the appearance of such a defect on the PVC film can be:
1) Violation of manufacturing technology at the manufacturing plant. There is an insufficient level of components in the PVC film base that are responsible for its plasticity. Or poor-quality connection (gluing) of multilayer film components.
2) Aging of the PVC film. Nothing lasts forever. During long-term storage, some molecules disintegrate, others evaporate, and others change their properties. Together, these factors degrade the plastic properties of the film over time.
3) Inappropriate storage and transportation. When storing or transporting small rolls in the cold (especially in the cold), any mechanical impact on the film may cause it to break at the point of inflection. It happens that a careless cargo carrier, pinning the roll with a heavy load, actually delivers some lumps of PVC film.
What should I do with a defective PVC film if the membrane vacuum press can’t work with small scraps? Send it back to the supplier in exchange for a new one, present an invoice to the transport company, or “pull the brakes” and write off the risks of losses? Resolve the current situation should be reasonable. Sometimes the extra hassle of 10-20 meters of PVC foil does not pay for the time, money and nerves. Especially if the customer has been waiting for their furniture facades in PVC film for a long time, and the time is already running out.
In this position, you should try to make the most of the remaining PVC film. To do this, you can use the dividing strip, separating the remaining part of the film from the defective sections.
However, most often, defects can appear along the entire length of the strip, along the edge of the roll. Then the film should be laid across the vacuum table of the press, using the same dividing bar. If you need to cover large parts, you will have to build a structure on the table that will prevent air from entering the film during the pressing process. To do this, a stack of chipboard scraps is laid out on the vacuum table in the places where the defective part of the film will fall, so as to exclude the possibility of deflection of the film in this place. The top piece of chipboard must have a LDCP coating that can seal the gap on the film.
After laying the film, the places of rupture should be sealed with a simple adhesive tape with a small margin for greater strength. Next, the area with the defect must be closed with any other material that excludes the possibility of heating it (you can cut off the chipboard or MDF). In the process of pressing facades, the film will fit tightly to the laminated chipboard layer on the one hand, and on the other – its tightness will be provided by ordinary adhesive tape. Since this section will be closed from the heating elements, the film will not stretch and deform here, while maintaining the strength of the connection with adhesive tape.
Thus, the PVC film on the MDF facades will be at least partially used, and not thrown into a landfill. It may even pay for all your efforts.
Some parts with a low edge profile can be lined directly under the silicone membrane. Sliced pieces of PVC film should cover the MDF parts with an overhang of 2-3 cm. However, with this method of pressing, there is a high probability of pinching (creases) at the corners of the facades.
The video at the bottom of the article shows a membrane-vacuum minipress that can use small pieces of PVC film and modify its remnants without any problems.
In conclusion, I would like to draw the attention of beginners that the usual gluing of breaks and cuts in the film with tape or other sticky tape will not give any effect. Under the influence of temperature, both the film itself and the adhesive from the tape will soften, and the pressure of 1 ATM. will only increase the gap more.