@ Dieter, I weighed one if the hinges on my wifes not so acurate scale & it was 1/4 oz. or about 8 grams, somewhere around there. It's hard to read, I think I need glasses. There is also the weight of the sheet rock screws I used, but I'm looking into some nylon wood screws, if they even exist. All in all, I was able to install the ballast in the belly, making for a nice tight swimming action. I still wish I could find a thinner hinge, that had the hinge pin down the center, instead of offset. I'll let you know, if I find any new materials.
Tim