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Bowl blanks can be dried using "chemistry". Submerging the blanks in various liquids can actually facilitate the loss of moisture. Before the pandemic, denatured alcohol was readily and turners would soak their blanks in it. Several sources of information on this- From the AAW- https://www.aawforum.org/community/threads/is-the-alcohol-drying-method-food-safe.9682/ From Mr. David Reed Smith- http://alcoholsoaking.blogspot.com/ and- http://alcoholsoaking.blogspot.com/2005/12/alcohol-soaking-q-and.html From David J. Marks- https://djmarks.com/drying-olive-wood-for-turning/ Alcohol should become more readily as the pandemic wanes. Another soaking method is using soap and water. As near as I can determine, this method was developed by Ron Kent- a Hawaii based turner. Even though he passed away several years ago, his website is still up and his original process is listed there. https://www.ronkent.com/techniques.php Using pretty much the same process, Ernie Conover discusses this in a Woodcraft blog- https://www.woodcraft.com/blog_entries/soap-in-your-bowl The AAW also has a discussion on this method- https://www.aawforum.org/community/threads/soaking-in-dishwashing-liquid.9087/ As well as the folks over at Sawmill Creek- https://sawmillcreek.org/showthread.php?33726-Drying-green-wood-using-dish-soap I have personally adopted this method and find it works extremely well. At this time, none of my bowls have cracked and show very little deformation. This method is also very inexpensive. One final "chemical" drying is to immerse the bowl blanks in a desiccant material. These materials absorb moisture from the wood. This video, from Ernie Conover and The Woodworker's Journal demonstrates the procedure- Although initially expensive, desiccant can be reused by heating the crystals in the oven to "re-activate" them. A discussion from the AAW- https://www.aawforum.org/community/threads/drying-green-wood-turned-bowls-in-silica-desiccant-beads.16924/ Although not as popular as some of the other methods, Some turners have tried to boil the bowl blanks. This PDF, from the Arizona Woodturner's Association and written by Bill Noble has some details- boiling.pdf In the final entry, we will look at sources that have lists of multiple methods of drying.
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Most finishing products have only three major components: 1. Resin. This is what remains and becomes the "solids" part of the finish. For shellac or lacquer, this is, well, shellac or lacquer. For an oil, an oil, usually linseed or tung For a waterborne finish, it's mostly acrylic resin. For a wax, it's a wax or combination of animal (beeswax), vegetable (carnuba), or mineral (petroleum paraffin) For a varnish, it's a cooked combination of an oil (linseed, soy, or tung) plus plastic (urethane, alkyd, or phenolic) For a pigment stain, the resin is known as "binder" to hold the pigments in place until a top coat is applied. It can be an oil, varnish, waterborne, or lacquer. 2. Thinner or solvent (or both) For shellac, alcohol solvent For lacquer, it's a soup of solvents, co-solvents and thinners. The mix is determined by economics (costs) and desired speed of evaporation and other properties. Usually, it's mostly a mix of alcohols, ketones, and petroleum distillates. So lacquer "thinner" is both a thinner and a solvent. For an oil, generally none For a waterborne finish, glycol ethers as "softeners" and water as a thinner For a wax, petroleum distillates as a solvent For a varnish, petroleum distillates, this time as a thinner only and not a solvent For a dye stain, the solvent (water or alcohol, usually) dissolves the dye. For a pigment stain, the thinner suspends the pigment particles and makes a wiping or spraying consistency. 3. Colorant Dyes - these are dissolved in the solvent and can be in a dye stain or a toner Pigment - these are suspended in the thinner and can be in a pigment stain, toner, or glaze Tar, yes, some finishes contain a tar, sometimes obfuscated as asphaltum or Gilsonite (tm). This is dissolved in the solvent as is sometimes used in stains or "walnut" danish oils. You can also make your own wiping stain by mixing some (non-fiber) roofing tar with mineral spirits of naphtha https://thefinishingstore.com/blogs/news/asphaltum-a-forgotten-finishing-gem There may be other, minor components such as Flatteners usually silica to reduce the sheen level UV protectors for outdoor finishes Other chemicals, especially in waterborne to enable emulsification, reduce foaming, etc.
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Tgif: Three Things: Why Finishing Is Confusing Tuesday, April 3, 2018
kmealy posted a topic in Finishing
Why is finishing so confusing? 1. Finish cans lie. Well, soften it a bit if you must, and call it mislead, but really. They don't always indicate what is inside. Examples; "Tung Oil Finish" - you would think this is tung oil. Nope, usually it's an oil-varnish blend or a thinned (wiping) varnish with little to no tung oil in it or even as a raw component. Linseed oil is more commonly used. "Water-based Lacquer" - if you have experience with nitrocellulose lacquer, a product that has been around 100 years, you will be surprised that this is really a different product that has nothing to do with traditional lacquer "Water based polyurethane" - again, it might have a small percent or urethane resin, but it's mostly acrylic and will look and behave much differently from the oil-based poly you've been using for years "Urethane - Oil blend" - well, this one is just a varnish. Varnish is made by heating (urethane) resins and oil until they become a different product - varnish. This is like going down the bread aisle and seeing a loaf labeled "flour-yeast blend." "Danish Oil", "Antique Oil", "Velvet Oil" etc. Well you get corn oil from corn, olive oil from olives, soybean oil from soybeans. We do not squeeze Danes, antiques, or velvet to get these oils, often thinned varnish or oil-varnish blends. Sometimes the MSDS (now known as SDS) will tell you what the true components are. A Google search for them is a place to start. But even then a lot hide behind "trade secret" "proprietary" or jam up simple mineral spirits with a fancy name like "Aliphatic hydrocarbon" The CAS (Chemical Abstracts Service) number is unique and cuts through all the BS, when it is provided on the SDS. Again, Google might help. 2. Myths. There are hundreds of myths out there about finishing. Bob Flexner's book on finishing is full of sidebars on them. Like all myths, they tend to get repeated and passed down as truth. Flexner has what he calls the "half-right rule" -- half of what you read or hear about finishing is true. You just don't always know which half. And yet the myths persist. YouTube and Pinterest have accelerated the spread of them. Abraham Lincoln once said, "Don't believe everything you read or see on the internet." I recently asked a major manufacturer's technical support group a simple question about one of their products. Their response was completely incorrect based on what I know about that particular product. And good luck asking the guy at the big box working in the paint department that used to be a truck driver. 3. Chemistry, not physics. Finishes work by chemistry - solvents, evaporation, polymerization, chemical reactions. You can't see this happen, but only the results. When you are woodworking, it's physics. You can see if an edge is square, if a joint is tight or gapped, if a surface is smooth or warped, etc. With finish, you apply it and sit back and watch. Some knowledge will help you get around the confusion.
