Geotextile Adhesive: 3M™ Holdfast 70

3M™ has developed Holdfast 70: A cylinder delivered, geotextile adhesive that can offer valuable benefits to the geotextile installer. The most common method for on-site seaming of geotextiles is with a hand-held sewing machine. These sewing machines can breakdown and require an on-site power source. Additionally, some seams can require large overlaps. Material is costly and downtime on the jobsite is very expensive.

3M™ Holdfast 70 is a high coverage geotextile adhesive with a fast drying formula (1-4 minutes). 3M™ Holdfast 70 offers two-surface bonding, moisture resistance bonds and is resistant to high temperatures. 3M™ Holdfast 70 geotextile adhesive is an alternative to sewing that offers speed, portability, reliability and convenience.

• Increased productivity and convenience
• No sewing machines and generators
• No expensive equipment maintenance
• 3M™ Holdfast 70 is fast drying and the sprayer is quick to assemble
• Saves fabric cost by reducing large overlaps
• Two-surface bonding

3M™ Holdfast 70 Bonding Methods

One Surface Bonding

Use this method in less demanding applications. Spray the most non-porous surface and bond within the 1-60 minute open time.

Two Surface Bonding

Use this method for permanent and more demanding applications. Spray both surfaces and bond within the 1-60 minute open time.

Spray Pattern

Unscrew the trigger stop/adjusting nut away from the trigger 3-4 turns and spray the 3M™ Holdfast 70 geotextile adhesive in a test pattern. For more adhesive output and a wider spray pattern, continue to unscrew the nut away from the trigger. For less output and a smaller spray pattern, screw the adjusting nut back towards the trigger. Hold the applicator 3-10 inches away from the geotextile to be sprayed and apply a uniform coat of geotextile adhesive. Note: The smaller the spray pattern, the closer the 3M™ Holdfast 70 applicator gun will need to be to the surface. The lace sprays in an elliptical pattern and should be sprayed at the patterns' widest point.

3M™ Holdfast 70 Geotextile Adhesive Performance

Overlap Shear Strength: 1 square inch bonds tested at 2 inches per minute separation rate at 75 degrees Fahrenheit.

Polypropylene to Polypropylene (Two-Surface Bond): 75 psi (typical)

Polyethylene to Polyethylene (Two Surface Bond): 35 psi (typical)

3M™ #78 Aerosol Spray Geotextile Adhesive

For smaller geotextile seaming projects, such as aeromodeling runways, US Fabrics suggests 3M™ #78 aerosol geotextile adhesive. 3M™ #78 aerosol geotextile adhesive is fast drying formula similar to Holdfast 70. Please see the Help Reference below for particulars.