August 28, 2012 2:30 PM
by John Baichtal
Eirik Taylor's Nokken-3 ROV is the latest iteration of his long-running submersible project.
The ROV housing itself was constructed using a sheet of plexiglas, which was welded first using acetone to hold the pieces in place, then glued later with epoxy. The potting substance used this time is laminating epoxy, commonly used to repair fiberglass constructs in marine applications. It's very expensive, but resilient and easy to use thanks to it's low viscosity. I made the mistake of not minimizing the potting volume before I starting pouring the epoxy. I had purchased 1,8 liters of resin thinking it would be more than enough, but I quickly saw that was not the case. With the insane cost of the stuff I was not willing to buy another batch, so I quickly chopped up some blocks of wood which I threw into the ROV shell. I'm not sure if the resin is simply exothermic while hardening, or if it reacts with wood, but either way this resulted in a foamy mass forming around the wood blocks. I don't think this will be a problem, but it doesn't look good. Had I known this before hand I would have used sand as fill mass, since it is chemically inert and inherently waterproof. "Standard Buccaneer" connectors from Bulgin were used for all connections on the ROV. This includes the motors which are permanently fastened. These connectors are waterproof down to 100 meters for 12 hours if assembled correctly. The LEDs were mounted inside of the ROV to save on connectors and the added complexity of waterproofing them.
[via Hacked Gadgets]
Filed under: Robotics, Water Craft