I built a sand box for my old Delta saw, which I no longer have. Please remember I did this many years ago, so I am going from memory. I will try to explain, basically you build a rectangle box with 4 sides and a bottom 3/4" plywood glued and screwed. The box has to be big enough to be able to set your saw inside of it. Once the box is built, set your saw inside of it. and trace your bolt patterns for your saw on the box bottom, drill holes in the bottom for some carriage bolts that you will need, the bolt length will be determined by the height of your box plus the thickness of your scroll saw. Next cut a platform that will fit just inside the box, set the platform in the box. now drill from the bottom of the box, so the bolt holes all line up (bottom and top). Take the platform out of the box and place your carriage bolts through the holes from the bottom up and fill the box with sand so the top platform just sits a little above flush. Now place the platform inside the box on top of the sand and line up your bolt holes, now place your saw on the platform and attach a washer and a nut and tighten down, this should help with some of your vibration, the sand will absorb it. I set my box on a bench where I wanted to scroll. remember you may want to find where you want it before you fill it with sand because it will be heavy. Sorry this was long, I hope I explained it. It seemed to help me.
Mark