First, you need to decide the size of your chestbox. The full size is 6 3/4" square, but if you are scaling yours down, calculate the exact size you need before you start.

Purchase some quarter round molding from your local home improvement store. Try to find the stuff that is about 1/2" on one edge and about 1" on the other (exact measurements will vary). See edge on angle of molding in the picture to the left. You will also need a piece of wood the same thickness as your chestbox.

Now, you will need to figure out exactly how much width the molding will add all around the box edge - glued on with the narrow edge facing toward the back, the wider edge attached to the box itself. Subtract the width of the molding from the size of your box on all edges. Cut a flat square in the size remaining. So, if the molding is 1/2" wide, remove 1" total from your dimensions in both directions on the box face.

Next, mark your cut lines on the molding based on the length of the edge of the box. Cut each piece with a 45 degree angle outward on each end.

Glue each length of molding you have just cut onto each edge of the box shape, using tape to hold it in place, and being sure it is flush with the front surface.

Once it is dry you can remove the tape and use putty to fill in the gaps and sand it smooth. The pic below is the putty stage. I'm using wood filler for the big stuff, but will surface it with auto putty, as it gets a nicer finish than wood filler.

Use a sponge sanding block on the box. This will allow you to get even, flat surfaces and more precise contours of your curved edges. Sand in a lenthwise direction to your edges, not up and down the curve. Keep your sponge either flat on the surface (if it's the face or the outermost edge), or perpendicular to the angle of the curve. This will allow you to obtain the proper contours. Also, extend the swipe of your sanding strokes beyond the corners on each edge as you sand. This will level the corners to each other and make a perfect 90 degree angle corner.

After putty, and sanding, I put on a coat of paint. The paint does two things. First, it seals the putty (which is particulary important if you are using a wood filler type putty, as it is quite easy to disolve with water), and it allows one to see more easily where the problem areas are. As you can see, there are still some cracks and irregular spots that need work. This is when I got out the automotive glazing and spot putty. This really allows for a super smooth finish.

I used alkyd rust paint. It's thick, sandable and dries relatively fast. After I do more surface work I will paint it again with the rust paint. I will finish the surface with gloss black - Krylon Fusion, probably.

After putty, sanding, putty, sanding, putty.... etc. and one final coat of paint, polished up. I ended up with -

- a nice smooth box which is ready to be molded.

This is a picture of the silicon mold I made from the box sculpture. The inset is just to show the mother mold, which is made (in this case) out of plaster bandage. I haven't cleaned up the mold yet, so you may see some spots in it. Normally the inside surface would be clean and smooth, allowing for nice clean molds.

This is the resin box casting in the process of having its components glued on. The panel "lights" - as you can see - are not finished yet in this photo, which is why they are not being glued on.