posted on August 13, 2020 08:33
You don't expect a woodturner trying to crack his or her bowls. They spend a lot of effort trying to learn how to prevent bowls from cracking. Trying to get bowls to crack is exactly what some have been doing. To make bowls visually more stimulating woodturners look for wood with large flaws or cracks. Failing that, they try to make the pieces crack by subjecting the bowls to harsh, rapid drying- just the opposite of what you would do if you were trying to prevent cracks from forming.
The reaon some woodturners want their bowls to crack is so they can fill them with a metal putty to create a metal inlay technique during the woodturning process. This metal putty, when dried and sanded, looks a lot like silver aluminum. The product is called Lab metal which is an aluminum filled putty that requires no mixing and can be thinned out and applied direct to wood. This filler is used to fill gaps in broken pieces of wood that will not be subjected to high stress.
Select a piece of wood that you would like to turn, but which contains flaws. Place the wood between centres and turn round. Turn the tailstock end flat and prepare it for your faceplate or four jaw chuck. Remount the wood to y our faceplate of four jaw chuck supporting the bowl at both ends with a live centre. Using a bowl gouge, start shaping the bowl. Since the wood is usually supported at both ends you can make agressive cuts. With the side of the bowl gouge, make fine finish cuts.
Clean the flaws out with a pocket knife or a sharp pointed ice pick or a small router. You may then apply the Lab metal filler to the flaws and imperfections in the wood. Spread the metal putty into the flaws in the wood working all around the gaps. The Lab metal will air dry in a few hours and can be applied in multiple layers. Lab metal can then be sanded with 60 grit sandpaper. After the final application the putty can be sanded and buffed smooth.
Lab metal can then be turned with a sharp bowl gouge. The gouge can cause some chip out of the material but can be easily re-applied. Deepen these flaws with the spiral cutting bit on the router while the bowl is on the lathe. You may then cut the inside of the bowl as for any other bowl in this case use a Forstner bit to make the initial cut. Place the toolrest very close to your work area when hollowing out the inside and use a bowl gouge for initial cutting. Finish with round nose scraper stoppping to check wall thickness with callipers.
Sand an apply finish while the bowl is still on the lathe. Not only does this technique save time but any remaining flaws could be revealed while the bowl is still on the lathe. Use a thin parting tool to part the bowl off, sand the bottom and apply a clear finish. Reverse-turn the bowl by remounting and turning off the bottom. If desired, turn a couple of decorative grooves on the bottom of the bowl.
Visit www.alvinproducts.com to get more information and how to order