“The speed is the big deal,” says Dean Lovett, business development supervisor for 3M's Industrial Adhesives & Tapes Division.
A typical concrete repair product can force contractors to wait 24 hours before they can get onto the newly repaired surface, he says, while an epoxy repair product may make them wait for days. Not so with a DP-600 crack filler. In as little as five minutes, it's hard. In roughly 15 minutes, it can stand up to a forklift. After as little as an hour, it can be painted.
The DP-600 crack fillers are the centerpieces of 3M's Concrete Repair collection, and they come in horizontal and vertical versions. DP-600 Self-Leveling is designed for floor crack fills, and as its name suggests, does not typically require smoothing. DP-600 Nonsag (or NS) is made for cracks on walls. Both are fast-curing urethanes, leaving a crack fill that will be at least as strong as the concrete. At the same time, the urethane is not as rigid as an epoxy. It has just enough flexibility to give the repaired crack some give when the surrounding concrete expands and contracts. “It reduces the tendency to crack again in that same area,” Lovett says.
The material will harden to any depth without cracking or shrinking, and it is solvent-free. It is so strong that it can also be used to anchor bolts and screws. And as a urethane, it will take most paints. “I have yet to find something that is not compatible,” Lovett says.
The DP-600 fillers are packaged in a duo-pack tube similar to those used with epoxies. DP-600 Self-Leveling is also sold in a two-compartment caulk cartridge with a mixing nozzle. This cartridge fits in a regular caulking gun, but it holds only 8.4 fluid ounces of material, compared to 12 fluid ounces in the duo-pack tube package.
The DP-600 came out in the duo-pak in 2003, and the caulk cartridge debuted in late 2004. “It is definitely new to the decorative concrete scene as this is a new market for us,” Lovett says.
For more information, visit www.3m.com/adhesives or call (800) 362-3550.