In 2014, I helped with some volunteer renovations at a place. I took some pieces of weathered 4/4 Oak that were removed and replaced to burn as firewood. Well the place was destroyed by fire a year later. An acquaintance did a lot of volunteer work there. I have one piece of the oak left, about 12 inches square. I would like to turn a round picture frame and put a picture of the place in it and present it to him. My goal is a round/circular picture frame about 8 inches in diameter with a five inch diameter picture. (my round piece of glass is 5.5 inches. ). The wood was weathered a bit but is mostly solid under the surface. Like all old boards it has cupped a bit. There is a crack down the middle of one side of the board, but not on the other. What can I do to the wood to keep the crack from getting worse or breaking through all together. CA glue? A resin filler? And how best to apply.?