Once you have sourced the wood, the next step is to rough turn a round platter. How thick the blank should be before turning depends on the wood, how wet it is, how large the platter will be and whether you want to end up with a fairly thin flat piece or a more concave shape. As you can see from my last blog, I started with some round big leaf maple blanks that were 4 or more inches thick. The wood was either dry or fairly dry. Since I am doing carving and inlay, I want the surface to be flat or just slightly concave. If too concave, the image of the characters would be distorted. So, the initial blank need not be more than 2 inches, and even 1.5 is often enough. This 10-inch platter ended up 3/8 inches thick.
On other platters made from exotic wood, I will generally have a border and a more concave shape. Those types of platters require 2+ inches to start with. Here the central area is turned shallower than the outer border. There is also the raised bead within the black lines. It ended up 16 inches by just over 1 inch.
So, if you are going for a thinner platter, and the wood is dry, you might want to try splitting your thicker blanks into thinner blanks. If they are square, this can be done fairly easily on bandsaw, although most bandsaws can only handle 8-10 inch pieces. My bandsaw has a large cutting capacity – up to 15 inches. Once you have it cut to the thickness you want, you need to cut it roughly round. I use a bandsaw with a 3/8th inch blade as it is thin enough to cut curves easily.
If your blank is round, then using the bandsaw to cut it into thinner blanks is not a good idea. Cutting round blanks on the bandsaw requires jigs or clamps and even then is inherently dangerous. I would highly recommend against it. I tried in the past and have had nothing but trouble, although fortunately no injuries. The last time, I ruined another new blade and also burned out the capacitors in my bandsaw (long story but I got the bandsaw in China and it was 3-phase, 360 volt; to use it here in the US, it had to be converted to 220 v and 2-phase, which required capacitors and reduced the HP from 3 to 2, which was one of the reasons it got stuck while making the cut and burnt out).
I have successfully put some thick round blanks between centers, turned the piece in from both sides as far as I could go, and then used a bedan or similar tool to part it down as far as I could safely reach. I then used a reciprocating saw to cut the rest of the way through. Prepare a few blanks like that in a row and you walk around vibrating the rest of the day!
Once you have the roundish blanks, you can put them between centers, true up the edge and then turn a tendon to fit your chuck.
If the wood is green or wet, you will need to leave the rough blank thicker and then dry it in a kiln, using denatured alcohol or just leaving it air out for several months. You can then remount it, true up the tendon, chuck it and true up the rest of the piece before sanding.
I generally sand both sides up to 120 or 180 grit to prepare them for the carving and inlay- which will be the subject of the next blog. However, if you are going to do woodburning without any border inlay, as below, then you need to sand all the way through the last grit (I do 1200, and then finish with a higher grit as I apply the lacquer). If you will be adding inlaid border, then you need to first do the inlay and all the sanding, and then do the woodburning.