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Welding Tips: Geotextiles
Nonwoven Geotextiles:
- Polypropylene. One of the easiest and most forgiving materials to wedge weld, especially if the weight is 8 to 12 ounces.
Using the GT-100 Hand-Held Wedge Welder, be prepared to move quickly. An average welding rate with the hand-held wedge welder is approximately 20 feet per minute, and closer to 30 feet per minute with nonwoven polypropylene geotextile weights of 4 to 8 ounces. Welding speed for the hand-held product is often limited to your "crawling" speed. Optimal temperature setting is 4.5 for lighter weights and 5 to 5.5 for heavier weights.
With the GT-200 Semi-Automatic Wedge Welder, the welding speed is increased to approximately 40 feet per minute for an 8-ounce weight, faster for less than 8-ounce and slower for heavier than 8-ounce. Temperature setting for 8-ounce or greater ranges from 1,000°F to 1,100°F, and for lighter weights, more in the range of 850°F.
· Polyester. A much more difficult material to wedge weld. Polyester seems to stick more to the hot wedge, and therefore, creates more friction and drag. Lightweight polyesters (4 to 6 ounce) require speed and finesse. Heavier weight polyesters (8+ ounce) are more forgiving but still require finesse.
GT-100 Hand-Held Wedge Welder. Not recommended for lightweight polyester since with a hand-held welder you can not achieve the speeds for optimal results. For 8-ounce or above, use a heat setting of about 5 or 5.5, and expect the welding speed to be about 10 to 15 feet per minute.
GT-200 Semi-Automatic Wedge Welder. On a 4-ounce polyester, one of our customers got good results with the wedge angle is the lowest position and flat and at field production rates approaching 100 feet per minute. If the wedge angle is not flat, the wedge may actually slice through the material. Although the melt temperature for polyester is higher than polypropylene, the setting temperature is slightly less at approximately 800°F to 900°F for lightweight, and 950°F to 1,050°F for heavier weights.
· Nylon. Current experience suggests using the GT-100 Hand-Held Wedge Welder since no field data has been collected for welding nylon with the GT-200 Semi-Automatic Wedge Welder. Wedge welding nylon requires higher temperatures and slower speeds. You may want to try placing a nonwoven polypropylene geotextile underneath the bottom layer of nylon material to increase the heat transfer rate. Expect slower welding speeds of 5 to 10 feet per minute, and temperature setting of 5 to 5.5.
Woven Geotextiles:
- Polypropylene. Easiest woven material to wedge weld. For best results place a 40 mil HDPE or other geomembrane beneath the two sheets of woven material (as a carry-board), using a silicon rubber roller, and the GT-100 Hand-Held Wedge Welder at a temperature setting of approximately 4 to 4.5, expect a welding rate of 15 to 20 feet per minute. Keep wedge perfectly parallel ... any angling will create edge breaks. geosynthetics, civil engineering, geotextiles, geomembranes, plastics, heat sealing, wedge welder, leister
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