One member asked suggestions for starting a project where the top would be turned and rounded and the bottom would remain square. Suggestions for cutting the corners off the top before turning were given to help reduce splintering.
Processing wood with cracks: Many comments were similar to the prior discussion on filling cracks and voids (March 2nd). Resin, resin with acetone, filling with CA glue, using epoxy, and soaking with a wood hardener were mentioned. Leaving some holes keeps it natural.
When there are cracks in a piece of wood that you want to use, it can be put between centers and make a tenon. Rough turn the outside shape then wrap the outside with blue tape first then fiberglass tape to keep it together until the cracks can be filled from the inside. Then turn the inside to about ¾” thick with the tape on. Fill the cracks with CA and sawdust. Another alternative is to fill the cracks with Liquid Diamonds casting epoxy, a water thin solution from Turner’s Warehouse that doesn’t leave bubbles: https://www.turnerswarehouse.com/products/liquid-diamonds-epoxy-casting-resin?_pos=1&_sid=c6bcc9288&_ss=r. It can be used with a mica powder to add coloration, such as antique copper. It takes more than a day to set and shrinks so more may need to be added. Remove the tape, check for outside cracks, fill those cracks, and do the final outside turning.
A member had made an acrylic bowl and applied Minwax wipe-on poly hoping for a smooth finish. It didn’t work: it congealed on the surface and made it rough. He had to sand it off.
Gary Frank still has wood sealer available to members by the gallon at a reduced cost from the retail price. It helps with slowly drying green wood.
A member had some pieces of mesquite that were very dry with a crack through the center and had intermittent cracks. Members talked about gluing those cracks, using some of the techniques discussed earlier.
Another suggestion was to seal cracks with extra blonde shellac (to prevent staining) then apply water thin CA and sand with 150 cloth-backed sandpaper right away. The sawdust from sanding mixes with the CA to help seal the cracks. This process must be done quickly before the CA sets. The sandpaper does gum up so have lots of it. CA and sawdust can also be rubbed by hand but cover your fingers with cellophane or a small plastic bag first to protect your skin.
Klingspor’s Woodworking Shop has a 10 lb. bargain box of cloth-backed sandpaper (medium and fine) for about $20. (https://www.woodworkingshop.com/product/bb00095/) (It looks like there’s a flat rate for shipping of about $8)
A few members have had problems with their chucks clicking. Nova, super Nova2 and a PSI have had the same problem. They can still turn, but hear clicking. Members suggested tightening the jaws, back off and then retighten when clamping on the tenon.
Another problem: sawdust in the lathe power switch. Advice was to blow it out periodically.
Discussion about using an expansion mount or mortise instead of a tenon:
- Advantages: A piece can be remounted on the lathe after it has been completed so it can still be worked on, such as removing a defect or applying a finish, which can’t be done easily once a tenon is removed. It’s easier to finish with some steel wool and doesn’t leave marks from the jaws like those on a tenon. Using a mortise gives more usable depth for the piece of wood in contrast to allowing additional room for a tenon.
- Other comments: The expansion depth could be 3/16”, ¼”, and even holds at 1/8” deep. Check for tightness, but don’t over expand. Retighten the chuck periodically. If there’s a small crack in the bottom of the wood, it’s better to use a tenon so the jaws will hold it together while turning. Use the tailstock whenever possible for support and safety. Some members fill the bottom circle left by the mortise with resin circles, contrasting wood (glued with Titebond) or laser text. With a mortise, members use speeds of 1300-1400 and even 1700 when turning without a problem.
If a woodturner has never had something ‘explode’ they are either lying or haven’t turned enough yet.
Be safe…don’t get too aggressive with cuts.
Cole jaws and Longworth jaws: use at the safe speed (under 600 rpm). A member replaced the straight bumpers with “GSC International, RS-4-1 Rubber Stopper, Size 4, Drilled 1-Hole”. They come in a 1 lb. bag that has about 28 stoppers from Amazon. $12.98 https://smile.amazon.com/s?k=GSC+International%2C+RS-4-1+Rubber+Stopper%2C+Size+4%2C+Drilled+1-Hole&ref=nb_sb_noss. Those were used with M6-35 1.00 bolts on Cole jaws. Ace Hardware or TruValue in this area have the M6 thread. Heat dries out the rubber in places like Phoenix, so these jaws should be stored in a cooler place. Using Armor All to keep the rubber pliable isn’t a good idea since the silicone in the Armor All can transfer to the wood and will prevent a finish from adhering properly.
Walnut oil was used to wet-sand a vase. The question was whether or not another finish, such as poly could be used over the walnut oil. Members suggested contacting Doctors Woodshop (who made the walnut oil) for their recommendation. The walnut oil could be the final finish but should be cured/aged for a month. Heating in an oven at 120-135° for about an hour can help it cure faster as can setting it out in the sun.
More sanding tips:
- With the lathe turned off, a power sander can be used to spin the object on the lathe for sanding problem areas.
- Sand in one direction, then reverse the lathe direction and sand in the other direction so both sides of the grain are lifted and sanded. (Caution: the chuck can unscrew itself from the headstock so a setscrew in the chuck must be tightened before reversing.)
- The direction can also be reversed on a drill when power sanding.
- Yorkshire grit and a friction finish can help with scratches.
- Use a damp cloth to wipe the piece and raise fibers.
- Hand sand in the direction of the grain.
- Lighten the touch when sanding; pushing too hard can leave scratches.
- Sand at 600-700 rpm.
- An inertia sander can help with sanding. Members gave two sources: https://woodturnerswonders.com/search?q=inertia&type=product or https://www.thesandingglove.com/The-Sanding-Solution.asp
Gluing segments: Bill McDonald glued 48 segments together to make each ring of a bowl. The two methods of using tape and the pairwise method were discussed. The suggestion was made to set the whole ring in a hose clamp, pull out two at a time to glue and place back into the circle, then repeat to keep them all tightened together when glued to maintain the angles in the circle.