Last week I talked to the folks from Trex about their new system for heat-bending composite decking and rails. Dubbed the Trex CustomCurve Heating and Bending Solution, it consists of a metal heating box, bending table, and various accessories.
The box has a door on one end, a control panel on the other, and a propane burner underneath. A thermostat keeps the interior at 295 degrees; a fan circulates the air (like a convection oven) to insure even heating.
According to the manufacturer, you can put wood plastic composite decking or railing in the box and within 30 to 45 minutes it will be soft enough to bend. You can tell when it's ready by measuring the surface temperature with an infrared thermometer; the correct temperature for Trex Transcend is 245 degrees. Trex hasn't tested the system with competing brands of decking but I suspect it would work with them too – though the temperature for bending might be different.
When the material is ready you take it out of the box, clamp it against the stops on the bending table, and leave it in place until it is cool enough (130 degrees) to retain its shape. You can speed the cooling process by spraying the piece with water.
The stops on the table are adjustable so you can set it to a variety of curves. If you don't have the table, you can fasten heated decking directly to the framing or bend it onto a home-made form. For that matter, you could soften stock in a home-made hot box but it would be difficult to control the temperature and provide even heating.
The box is sized to hold two 8-foot pieces of material. If it takes 45 minutes of heating time, then a crew could bend 20 plus pieces per 8-hour day.
I asked the people at Trex about the HEATCON bending system (which relies on silicon rubber heat blankets) because I had seen it demonstrated at JLClive. They said it works fine with PVC decking but has a hard time bringing wood composite to a high enough temperature to bend.
Before anyone reading this gets too carried away, I should warn you that the system is very expensive. The CustomCurve heat box sells for $5,250 and it's another $699 for the bending table. Trex doesn't expect to sell many of these to individual contractors – they think most of their sales will be to material dealers who will rent or lend the device to the contractors who buy decking and rails from them.
The heat box weighs 340 pounds and is just under 11 feet long. It requires 110-volt 15-amp service and in 70-degree weather will run 6 hours on a 20-pound cylinder of propane. The CustomCurve system is produced and distributed for Trex by CurveIt LLC. You can see the product in action in this video from the manufacturer.