Repair Method D: hot air welding
When welding plastic, a common misconception is that the welding rod should flow into the base material and produce a fillet type weld. With metal welding, this may be true, but for plastic welding the strongest welds are those where the filler rod will retain its basic shape after being pressed into the joint.
This can easily be seen when using the R-13 ribbon. Aside from some distortion of the edges, the basic profile of the material remains intact after the welding process. (Figure 5)
When welding very thick materials it may be necessary to make multiple passes with the welding rod. If possible, stagger the starting points of subsequent passes to achieve the strongest possible weld.
Once you complete the weld, you should not immediately pull the welding rod away from the surface being welded. This may cause the rod to break away from the base material. A better way of ending the weld is to remove the heat source and continue to apply pressure with the welding rod directed at the base material for several seconds. To remove the rod, release the downward pressure and twist the rod to break it off. (Figure 6)
Using Speed Tips:
When using the speed tip that comes with the 6055 welder or the optional speed tip for the 6050HA welder (PN: 6050-NHS1), the principle is the same as with the tube tips or reduction nozzle; heat the rod and the base material sufficiently to get the two to stick together. The difference is the speed tip allows the heat to be more easily confined to the joint being welded and allows the rod to be more rapidly heated. This allows the user to make faster welds with less heat escaping into the surrounding areas. Using a speed tip also allows some shaping of the finished weld because the filler rod is melted on all sides and the tip can be dragged over the surface of the weld to press the material into shape.
Because you cannot see the area being welded where the rod and base material are joined, it is our recommendation the weld be tested after it has cooled to ensure adequate penetration.
Heat levels and air speeds are roughly the same as with the tube tips and reduction nozzle. You will be able to make additional adjustments based on your need for speed and the thickness and type of base material.
padded dash repair
Clean and V-Groove Damaged Area
Clean the damaged area with 1000 Super Clean Plastic Cleaner. Bevel the edges of the area to be welded with 6275 Electric Die Grinder and open up a cavity at least 1/4” deep in the foam backing and vinyl cover. Sand and bevel the vinyl cover around the cavity to allow for featheredging of filler.
Fill Cavity with Urethane Welding Rod
Using the 5003R1 Urethane Welding Rod, start your weld at the bottom of the cavity using your Airless Plastic Welder. Fill the cavity up with melted plastic and spread it out so that it overlaps the edges of the vinyl cover about 1/4”.
Sand and Apply Padded Dash Filler
After allowing the weld area to cool, grind the weld area smooth with the 6407 Drum Sander attachment for the 6275 Electric Die Grinder. Rough up the surrounding area to improve adhesion of the filler. Mix 2050-9 Padded Dash Filler and apply with plastic squeegee. Cover an area larger than the weld in order to feather out the repair to a smooth contour.
Finish Sand and Apply Texture Material
Allow the filler to cure at least 15 minutes, then sand to a smooth contour. Finish sand with 220 grit paper. Retexture the panel with 3800 Flex Tex flexible texture material according to directions on Page 9. Do not try to spot retexture. Retexture and blend the leading edge or most visible area of the pad all the way across. If there is a noticeable difference in texture, retexture the entire pad.