I’m not a painter, but it might be worth getting a couple of these Trailer fenders for $19 to practice on. https://m.northerntool.com/shop/tools/product_200649345_200649345
To seal it and prevent cracking, look at what they do with chain saw carvings. This may help. https://forum.woodcarvingillustrated.com/forum/woodcarving-illustrated/woodcarving/chainsaw-carving/1124420-preserving-a-chainsaw-carving
Get plastic containers like these... https://www.amazon.com/dp/B07SYC9TX9/?tag=atomicindus08-20
glue, screw or pop rivet the lids to the bottom of the container. Snap as many together as need to make a log.
I think you could build block to hold pieces of bandsaw blades (maybe sharpen the edge like a knife) to the shape you need. Then use a press or a hammer to cut the pieces. I’ll try to post a picture of what I mean later.
Mc master Carr has 1” socket head screws with 3/4” hex. You could turn down the treads to fit inside the 1” tube, secret with a couple plug welds.
Bushing May by better than a bearing, less likely to rust.
One of these may work to mold a cast/splint.
https://www.amazon.com/dp/B00WW8KIRI/?tag=atomicindus08-20
https://www.amazon.com/dp/B004MFLU4Y/?tag=atomicindus08-20