I go into more detail in our YouTube video (see above) but I chose a piece of 1×12 with a pretty bac twist and cup to it and needed to flatten it first. You can easily enough plane out a cup, but it’s not so easy to remove a twist. The video provides some more details on this process. If your positive your board is flat in relation to the spindle, then move on to step 2.
The entire process is shown and described in the video above.
Now that our board is flat, we can trace the union, this helps the staining process to easily lay masking tape and stain the union Blue and the Stripe section Red.
After about 15 minutes of the stains drying we can begin to carve, first the stars, and after a bit swap, the stripes can be carved with a 1/8" bit followed by the perimeter with the same bit.
The process is quite simple once you do it once while following along with the video.