A “Hydraulic” Hammer?!
When Phil Poirier, of Bonny Doon Engineering, showed his new urethane hammer to Eddie Bell, vice president of manufacturing at Rio Grande, Eddie was immediately excited by its possibilities for jewelry-making and said, “Man, that’s a hydraulic hammer!”
Given that Phil is the designing mind behind the hydraulic presses and innovative tooling at Bonny Doon, this wasn’t perhaps a great leap, but we all LOVED the appropriateness of this description. Then, at a trade show soon after, when Phil showed the urethane heavy-duty forming hammer to attendees, their responses, more than once, were along the lines of: “Oh! I already have a plastic hammer.” That told us that we had some ‘splainin’ to do around this hammer. So, okay, the Bonny Doon urethane forming hammer does rather look like a colorful plastic hammer. But it is so much more than that! First, the faces are not plastic, they’re urethane. What’s the difference? All the difference in the world; here’s how:
Hydraulics & Incompressible Urethane
When you think of hydraulics, maybe you think of the “jaws of life” you’ve seen on the news, or maybe you think of your car’s brake system. Maybe you think of some other equipment that magnifies some amount of input power—hand or electric—into a force that can be orders of magnitude greater. The science of hydraulics, after all, is rooted in the fact that certain liquids cannot be compressed. When you contain them and apply pressure, the liquid forces itself into any direction left open to it—such as into opening the massive jaws of life or pushing the brakes against the car wheels to stop your car.
Like the liquids used in hydraulic equipment, urethane is an incompressible solid and behaves very much like the liquid in a hydraulic system when pressure is applied to it. The urethane cannot compress, so it spreads outward in any direction open to it. Then, when the force is spent, the urethane instantly returns to its original size and shape.
What Does This Mean for Metal Forming?
What it means is that a single blow of the urethane hammer affects considerably more surface area than a plastic hammer does (in our unscientific, unofficial testing, about 14 times more). Not only does each strike do way more work, you’ll need fewer strikes to get your job done. Urethane is available in a variety of hardnesses, measured by durometer, that let you control how much “flow” you get. And, urethane will not mar the metal or leave any hammer marks behind—you could even form a piece of metal you’ve already textured without distorting the texture.
Says Phil, “The softer urethane is good for forming lots of volume but cannot impart fine details well; conversely, the harder urethanes can impart fine detail but do not form large volumes well. When using the Bonny Doon hammers, I’ll use the soft (orange) hammer head to form thin metal (26 ga. or thinner) over the synclastic stakes so the most metal gets moved with each strike. I’ll use the hard (red) urethane head to form thicker metal gauges (24 ga. and thicker) over both synclastic and anticlastic stakes.”
Plastic hammer? Not even close. Available in three sizes, the Bonny Doon “hydraulic” urethane forming hammers will give your metal forming every benefit a plastic hammer could and then a whole lot more.
Give one of these amazing hammers a try and let us know what you think—even better, show off some of the work you’ve done using your “hydraulic” hammer.