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NOVAWELD-branded wedge welders were first introduced in 1990. By 2002, nearly 5,000 GT-100 hand-held wedge welders have been manufactured and purchased world-wide by geomembrane and geotextile contractors as well as for industrial applications. To assist engineers in specifying wedge welding geotextiles over other methods such as sewing, our president, Glenn Lippman, chaired an ASTM subcommittee resulting in a revised standard known as D-4884 or D4884-96 (as amended) Standard Test Method for Strength of Sewn or Thermally Bonded Seams of Geotextiles. ASTM approved wedge welding geomembranes with D4545 several years prior. To learn more about ASTM standards for geomembranes and geotextiles, visit ASTM.
If you are an engineer or contractor desiring to specify wedge welding for seaming geotextiles, please either contact us, or use any of the following references, many of which have been used to convince project managers to allow wedge welding.
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Comparison |
Wedge Welding
Sew with Heat |
Conventional Field Sewing |
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Overlap |
2-inch Minimum; 4-inch Maximum |
8-12 inch Minimum |
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Layout |
Flat Overlapped Seam |
Obstructive Prayer Seam |
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Patching |
Simple using GT-100 Hand-Held Wedge Welder |
Virtually impossible with sewing machine |
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Equipment |
Simple, Using GT-200 Wheel Mounted Wedge Welder for Continuous seams |
Complex, requires frequent maintenance and membrane puncture risks with lost/broken needles |
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Third Party Materials |
None |
Thread, Needles |
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Field Seaming Rates |
Up to 4 acres per day |
Up to 1 acre per day |
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Seam Strength (% MARV) |
80% to 100% (4-60 ounce per square yard) |
20% to 80% (6-20 ounce per square yard) | |
Lower Costs ... Less CQA Problems
- Quicker Installs (up to 4 acres per day)
- Less Material -- Less Overlaps
- No Equipment Maintenance -- No Jamming
- Less Overhead -- Fewer People
- Redirect Personnel to Other Jobs
geosynthetics, civil engineering, geotextiles, geomembranes, plastics, heat sealing, wedge welder, leister
Other Facts:
- Geotextiles -- Broader range of materials, from 4 oz/sq yd to over 60 oz/sq yd
- NWNPPP, NWNPPET, NWHS, SFW
- Geocomposites -- GCLs, GNGC, GMGT
- Wedge Welding as compared to Sewing:
- No Complex Sewing Equipment
- Material Savings
- No Broken Needles
- Faster Installation
- No Lost Needles
- Flat Layout
- No Thread
- Simple Patching
- No Sewing Personnel
- Highest Seam Strength Efficiency
Geotextile Seaming Comparisons
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Seam Specification |
Material Overlap |
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No Seam Specification |
12-inch Minimum Overlap |
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Sewn Seam Specification |
8-inch Minimum Overlap |
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Wedge Welded Seam Specification |
4-inch Maximum Overlap | geosynthetics, civil engineering, geotextiles, geomembranes, plastics, heat sealing, wedge welder, leister
BPR versus OPR Wedge Welding Methods
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BPR=Base Pressure Roller |
OPR=Opposing Pressure Roller |
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Ideal for Field Sealing Nonwoven Geotextile Applications |
Ideal for Factory Sealing Geomembrane Applications |
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Seals 4 to 60 oz/sq yd - Nonwoven |
Seals 4 to 10 oz/sq yd - Nonwoven |
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Few moving parts |
Lots of moving parts |
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No Jamming -- No Down Time |
Jams Frequently -- Lots of Down Time |
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2-inch Material Overlap |
6-8 inch Material Overlap -- Wasted Material |
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No preparation needed |
Geotextile preparation required -- trimming |
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Fast -- Up to 50 feet per minute |
Slow -- 5 to 10 feet per minute |
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Versatile - Able to do T-Joints, GCLs |
Not able to do T-Joints or GCLs |
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NOVAWELDTM-branded GT-200
Manufactured by Nova Products Mfg., Inc. |
DemTech: ProWedge
Sinclair: TRIAD & Spec (Now Miller Weldmaster)
Leister/Concord: Astro
PWT MicroMouse | |
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