I mix my own oil/varnish because I have control of the ingredients, it is always fresh, it contains more solids than the commercial finishes and therefore builds faster, and it is less expensive to use than commercial products. My opinion may be somewhat biased because I learned to mix my own finishes before any of the commercial mixtures were available.
My mixture is simple. The ingredients are linked to the discussion below.
The proportions aren’t critical. If there is any error in the proportions, it should be towards a lesser amount of oil, and a greater quantity of thinner. Additional oil will improve its wiping properties, but it will also increase its drying time. Too much oil can soften the finish.
The 1/3 Tung Oil
I use whatever good quality 100% Tung Oil is available at the local paint store because I like to inspect the cans for signs of aging before buying. Old Master’s and Hope’s are the brands usually available, and both are good quality. Woodcraft stores sell a good quality Tung Oil under their own label.
Boiled Linseed Oil could be used, but the resulting finish is softer and it will become darker faster than with Tung Oil. Changing the oil that is used to a 50/50 mixture of Tung Oil and Boiled Linseed Oil seems to better enhance the grain in highly figured wood such as Maple.
The 1/3 Varnish
In my opinion, McCloskey’s, “Man’O War”, Gloss Spar Varnish (in the red can) is the best varnish on the market for turned wood. It has all of the benefits of a spar varnish because of its Tung Oil, phenolic, and alkyd resins. Its only disadvantage is that it is more expensive than other varnishes. A similar spar varnish is available as an Ace Harware house-brand in the green can. I have always preferred the traditional alkyd varnishes for furniture and turned wood, but they are getting difficult to find, and I have limited experience with the floor finishes mentioned earlier.
The 1/3 Thinner
Pure Gum Spirits of Turpentine are used for the thinner because the natural oils become a part of the finish and enhance the qualities of the varnish. . Other thinners do not become a part of the finish. Turpentine substitutes are nothing more than an expensive form of Mineral Spirits (paint thinner) that evaporates more slowly.
Either 1-K kerosene, VM&P Naptha, or Odorless Mineral Spirits could be substituted for the turpentine. Naptha dries faster than Turpentine, Kerosene dries slower and mineral spirits dries only slightly faster, but also gives the mixture a shorter shelf life. None of them impart anything to the finish.
Wipe-On Application
The wipe-on, wipe-off, wait, buff with steel-wool, and repeat, application is familiar to nearly all woodturners who have ever used a commercial finishing product such as Watco Danish Oil.
A “finishing-ball” is easier to use than a paper towel, and it doesn’t fall apart. Prepare the ball by making a golf ball sized wad of cheesecloth, and then wrapping it in a 6” square of cotton cloth. A sheet of paper towel that has been folded into as small a square as possible can substitute for the cheesecloth inside the ball.
A paper towel works well for small projects. Paper towels are always changing. I used Viva for years because it was softest and most lint free that I had used. Then I went to Bounty. Now I have gone back to Viva because it is on sale more often. I fold the towel twice in the long direction, and then roll it as tight as possible to make an applicator that will keep my fingers out of the finish.
The directions for application are simple-
Apply a heavy coat of finish and keep it wet for several minutes. Sand the first coat with 400-grit wet-dry to form a slurry that will act as a grain filler. Add more finish as it starts to dry. Sanding is omitted after the second coat.
Wait a few minutes until it becomes tacky.
Remove all of the finish with a soft cloth or paper towel.
NOTE:
This step is a problem for most users of oil finishes. When the directions say "wipe dry" they mean "DRY". It should be wiped dry enough that there is no smudge left from touching it. If you can see a fingerprint, wipe it some more with a clean towel.
Wait overnight.
Buff it back with steel wool.
If the finish is not removed as a fine white powder by the steel wool, wait until the next day and try it again.
Repeat Steps 1 through 5 as many times as required to achieve the desired gloss. Sand in the 2nd coat with 600-grit wet or dry sandpaper. Apply as many coats as needed to leave a glossy finish after waiting overnight, 5 or 6 ius normal depending on the wood, and then add one more. The highest gloss we can get with an oil finish is when the gloss of the dried finish is the same as that of the new coat that we are applying, and that will take at least 6 coats on most woods, but dont be surprized by the gloss that you will get after 12 coats.
Water Borne Finishes, a dismal past and a bright future
These finishes have been around for about 20 years, but they have never been able to compete with the traditional oil finishes.
But. all of that is changing.
There is a new generation of waterborne finishes coming into the market that are every bit as good as the traditional oils. Enduro, is one of them. It has been available for several years by the gallon via mail order, but it is now made by General Finishes and on the shelf at Woodcraft stores. I have been pleasantly surprized by the Enduro product. It was originally discovered to be an excellent finish for a pen, but I have been using it on other turned wood, and I like what I am seeing.
The High Performance, also be General Finishes, and the Deft Acrylic are also promising waterborne finishes. I will be writing a separate article about these new finishes because I am using them and I like the results.
I haven' used any of the waterborne finishes in the past because I have never liked the results. These finishes have always had the potential for solving many of the problems that are associated with traditional varnishes and oils because they penetrate well, do not discolor the wood, and have a hard durable surface film that is clear and will not change color with age.
However, the very fact of not changing the wood color has always meant there was no difference in color with varying grains, and therefor the "chatoyance" is missing from highly figured woods such as the Curly Cherry or Striped Maple.
Waterbornes have also had a “bluish” tint and poor reflective qualities that often leaves the wood with a “muddy” appearance.
The manufacturers have created another problem for themselves by calling their waterborne products by the same names as the traditional finishes. Then they have taken on the task to make them behave the same when they are not and never will be. Some brands have disguised the fact that their product is water borne, and we have to read the fine print on the back of the can to determine that water is actually used for clean-up.
But, all of that is changing, and we may soon be forced into using them by Federal regulation. Fortunately, the manufacturers are starting to make better waterborne finishes, and the transition will be easier.
A Danish Oil (my version)
I blend my own Danish-type Oil because it is 1/3 the cost and better than anything on the market. It has a longer shelf life and it doesn't get as dark as the commercial Linseed Oil finishes. There are also some varnish resins added to gove it more solids and a better surface gloss. It is simple to make in quantity, but the ingredients may be reduced proportionalelt for make smaller quantities.
1-gallon Boiled Linseed Oil
2-gallons Unscented Mineral Spirits
1- quart MeCloskeys Spar Varnish in the red can
Add ½-cup of Japan Drier if you want it to cure faster
when the shop temperatures are below 65˚F at night.
Use equivalent smaller quantities if you don’t want to make it in a five gallon bucket. I use a lot of it, and store it in the original gallon containers. It will have a shelf life of several years in a closed can.
This is not an ideal finish, but it is inexpensive, and just a good as or better than Watco or the other Danish Oils that are found on the store shelves.
The worst that can happen if a large quantity is stored in an open buck is that the solids will start to form a "flock" in the liquid. Don't throw it out when this happens. This stuff is an excellent preservative finish that is better than anything commercially available for wood decks and outdoor furniture.
Other Ways To Apply An Oil Finish
There are several other ways to apply an oil finish that are quicker than the traditional "wipe-on-wipe off-buff-and repeat" application.
Wet Sanding Application
An alternative application is sanding with wet/dry paper while the piece is spinning on the lathe, using the finish as the lubricant. A suggested application is dry-sand through about 150-grit, and then wet-sand with the finish, starting at 180-grit and continue through 600-grit. Wipe the slurry from the wood surface before going on to the next finer grade. When you are done sanding you are done finishing. Let it dry overnight and buff with steel wool.
Al-Oxide or Garnet samdpaper can be used with the oil. The difference is that the binders that hold the Al-Ox grit to the paper will soften in the oil and the grit will come off the paper. The resulting slurry will do a good job of sanding the wood, The only problem is that it may have to be discarded after each use.
The Submarine Finish
This works very well for small articles - weed-pots, vases, etc. It also works for large pieces but will require larger quantities and containers. It may take several hours to days to complete the finish, but the actual time spent working on the finish is small.
Dry sand the piece through 400 or 600 grit.
Then submerge the piece in a container of the finishing liquid for at least a couple hours, or until it is saturated.
Allow it to drip dry. Set it aside for a couple days or until the finish is completely dry. If necessary, wipe off any excess that refuses to dry.
Buff it with a soft linen wheel that has been charged with a little Tripoli compound, followed with a White Diamond and wax. The Beall and similar buffing wheels that are specifically made for wood finishing are the best. However, any hardware store cotton wheel can be used when nothing else is available. I always recommend using these first because they are less expensive, and then ordering the expensive wheels from Craft Supplies or other suppliers after determining that you want to continue using this finishing method.
I use this method for finishing large pieces that are turned from Western Red Cedar and Redwood burls, but it works for hardening any soft of punky wood that was allowed to spalt too long.
The wood is turned to its final form and thickness and rough sanded while it is still wet. Then it is placed in a tub filled with enough of the home-brew mixture to cover the wood, and left to soak until all of the water in the wood has been replaced with the mixture. This may take several days to several weeks. Then the piece is removed from the tub and set aside until the “finish” in the wood has cured. Again, this can also take several days to several weeks.
When all of this has dried, the wood is put back in the lathe given a final sanding, and the bottom is finished. A higher gloss can be brought out with a buffing wheel.
Transluscence
The secret to "transluscence" is saturating the wood with an oil finish, and there is no better way to do that that with The Submarine Method" described above.
This will give a translucent quality to Ponderosa Pine, Norfolk Island Pine, and Cottonwood, that I know of. There may be other woods that will exhibit the same effect, but these are the ones that I have used.
The wood needs to be turned thin, and sanded before submurging it in the finish. "Thin" means no thicker than 3/16", and closer to 1/8" if possible.
