Heat Welding Heat-Sensitive Flooring
December 9, 2008
As the popularity of heat-welded sheet vinyl flooring continues to grow in commercial applications, installers heat welding these products should be aware of differences when welding certain sheet flooring products based on their construction and factory applied finishes.
The wear surface and surface coatings of these flooring products react quickly to heat from the heat welder.
Typically heterogeneous constructed flooring products have been known to experience this reaction in the clear vinyl (unfilled) wear surface. The wear surface reacts to the heat before the material in the groove gets hot enough to melt and fuse with the welding rod or thread.
In addition many commercial flooring manufacturers are applying urethane coatings to the wear surfaces of their sheet 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 reaction can be seen as a shiny area, or as a visual distortion with a yellow/brown discoloration and cracking of the wear surface usually at a 90-degree angle to the seam.
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. (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.
To prevent costly callbacks or replacements, specialized nozzles have been developed which precisely focus the hot air from the nozzle to the groove and minimize the excess hot air flow from damaging the flooring surface adjacent to the groove. (Photo 2) The tips are available for both round and half round welding rod.
Due to the design of the tips, they will require an accurate angle to seam; keeping the nozzle the correct distance from the groove, the tip must also be kept in alignment with the groove or the airflow will damage the flooring surface.
The use of a roller guide attached to the heat welder helps to control this and results in a more consistent heat weld quality. (Photo 3)
For longer seams an automatic heat welder fitted with these specialized nozzles offers a distinct advantage. The welder can be fitted with either a round or half round nozzle. (Photo 4)
Additionally there are new nozzles specifically designed for detail work such as flash coving and repairs, the tips have a unique design which gives the installer excellent control and focuses heat just to the weld rod and groove. (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.