Heat Welding Heat Sensitive Flooring
May 31, 2007
As the popularity of heat welded sheet vinyl flooring continues to grow in commercial applications, installers working with these products will become aware of unique requirements.
Just as heat welding linoleum creates unique requirements based on linoleum’s unique construction (see Nov./Dec. 2006 Floor Covering Installer magazine, pg. 42, “Heat Welding Homogeneous Sheet Vinyl Flooring”), heat welding certain PVC sheet vinyl floors creates unique challenges for installers due to the construction of these floors.
The wear surface and surface coating of these flooring products tend to react quickly to heat from the heat welder. This reaction can be seen as a shiny area, or as a visual distortion with a yellow/brown discoloration along the edges of the seam (See photo #1)
Typically heterogeneous constructed flooring products have been known to experience this reaction in the clear vinyl wear surface. The wear surface absorbs and reacts to the heat before the material in the groove gets hot enough to melt and fuse with the welding rod or thread. (Heterogeneous flooring products are manufactured in distinct layers: wear surface, print layer, and a vinyl, fiberglass or felt backing.)
In addition, many commercial flooring manufacturers are applying urethane coatings to the wear surfaces of their flooring, both heterogeneous and homogeneous. This coating enhances the initial protection of the flooring during and after installation, and gives the end-user wider maintenance options. These urethane coatings can also react to the heat before the weld rod fuses with the flooring.
The resulting damage can range from a very slight visible surface distortion or scorching along the edges of the seam to a more visible surface texture distortion and/or a yellow to brown discoloration (See photo #1). Often the damage is not visible to the installer welding the seam until viewed from a standing position.
Seams with a slight scorching can sometimes be improved by applying a commercial floor polish, however polish will not disguise severe scorching or shiny seams.
This scorching of the floor surface at the seam is caused by the excess flow of hot air from the conventional speed tips onto the flooring surface adjacent to the groove. Some installers have adjusted the temperature and speed of their heat guns and the angle of the tip to the floor to prevent damaging the floor. These adjustments require practice. Inconsistent technique will result in cold spots in the weld or scorched areas along the seam.
To prevent costly callbacks or replacements, a new specialized state-of-the-art heat-welding nozzle has recently been developed (See photo #2).
The new Turbo Precision Nozzle (TPN) has brought a much-needed solution to this problem. It has 13 tiny preheating jets that deliver the hot air precisely into the groove, thus eliminating any shining or scorching damage on the floor surface adjacent to the groove (See photo #3).
Due to the design of the nozzles, they may require a slower speed of movement and an accurate angle of the tip to the floor - not too close, or especially not too far from the groove. The tip must be kept in alignment with the groove or the airflow will damage the flooring surface (See photo #4).
The manufacturer of these nozzles also offers an automatic heat welder that accepts these new nozzles. This is a distinct advantage to these types of flooring (See photo #5).
With the proper equipment and a little practice, an installer can heat weld the wide range of commercial flooring products available today with better consistency and visual results.