Mineral Oil-
Preparation for use as a finish.
It’s a simple matter to prepare your own mineral oil-
Why would you want to go to the trouble of making your own? For one thing, it’s much less expensive. And if you make your own, you know without a doubt what’s in it: nothing but mineral oil and beeswax, both of which are odorless and “food safe.” You can assure your potential customers that your finish contains no toxic substances.
However, the devil is in the details, specifically in the “measured amounts” of oil and wax that go into the mix. Directions and recipes are everywhere but are often confusing because of the units used to measure the two ingredients. In this article I hope to clarify the situation and give directions that are both clear and practical. Also I describe a simple balance that you can make if you don’t have a set of scales for weighing the beeswax.
The Finish
Because mineral does not cure to a solid, you might think that the wooden surface to which it is applied would always remain “oily and greasy.” Such is not the case. The oil seems to soak into the wood so that after a day or two, it no longer exhibits an oily and greasy feel.
Adding beeswax to the mineral oil provides the extra benefit of sealing the pores of the wood. Additionally, if the surface is buffed with a cloth or paper towel, it will exhibit a soft sheen that enhances the beauty of the piece. I think it is an ideal finish for items that will be used – bowls, plates, rolling pins, and so forth.
The photos below show a plunder bowl and a small plate, both with a mineral oil – beeswax finish. Neither exhibit the slightest hint of oiliness or greasiness.
Cooking the Brew
Beeswax melts at a temperature of about 146 F, which is well below the boiling point of water. We can use a water bath to heat the mixture and be confident that we will not overheat it or scorch the material near the bottom of the container.
Place a shallow pan on your stove. Add water to a depth of about 3/8”. Heat the water to a convincing simmer; it doesn’t have to boil.
Put the beeswax and mineral oil in the “melting pot” and then place it in the water bath. In just a few minutes the wax will melt and the mixture will become transparent. Stir gently with the blade of a table knife. As soon as the wax has melted and mixed with the mineral oil, you can remove it from the heat. The mixture will be opague after it cools.
The melting process will go much faster if a metal container is used instead of one made of glass. After melting the wax, you can pour the mixture into a glass jar or plastic container if you wish.
Where I live, onion dip comes in a small metal can with a plastic lid. I use one of these to store the mixture. Also, tuna is packaged in shallow metal cans that are ideal for heating somewhat greater quantites.
Fire hazard? Warnings are everywhere about the hazards of heating an oil and wax mixture. However, I think the risk is minimal in this project because of the low temperatures involved. If you have a gas stove, what you can do is heat the water to near the boiling point and then shut off the flame before you bring the oil and wax anywhere near the stove. The pan and water will hold enough heat to do the job.
The Source of Confusion
Many sets of directions use ounces as a unit of measure without making it clear whether the
unit is an ounce of weight or an ounce of volume. Others give the quantity of beeswax as a volume, and it’s not obvious how you measure the volume of a material that may appear in the form of an irregular block, a bag of flakes, or a pack of random chunks and granules.
Practically speaking, the beeswax should be measured by weight using ounces (of weight) or grams. The mineral oil should be measured by volume using fluid ounces or milliliters.
What I have determined:
The following ratio gives an acceptable mixture:
Beeswax: 1 gram Mineral oil: 5 ml (milliliters)
In these proportions, the solid beeswax is measured by weight (grams) which is easy to do. And the mineral oil is measured by volume (milliliters) which is also easy.
But most people (in the US at least) are not familiar with grams or milliliters, so I have not yet clarified anything. Here is the same proportion but in different units:
Beeswax: 1 ounce (weight) Mineral oil: 4.8 fluid ounces (volume)
Here we have two different kinds of ounces. An ounce of weight (oz-
An ounce of volume, a fluid ounce (fl oz), is 1/16 of a pint and may be m
easured
with a measuring cup from the kitchen. Measuring cups are almost always graduated
in fluid ounces, fractions of a cup, and sometimes milliliters as well. A cup is
the equivalent of 8 fluid ounces or about 237 milliliters.
Here are more combinations that have the same proportions:
Bwax: 2 oz-
Bwax: 4 oz-
Bwax: 3.33 oz-
Take a shortcut!
Beeswax ordered from woodworking suppliers (Craft Supplies
, Klingspor, Packard Woodworks,
etc.) comes in packs or bars measured by weight in ounces and grams. For example,
one packet from Woodcraft contains 4 oz. If you mix the entire packet with 19.2 fluid
ounces of mineral oil, you will be good to go.
Or you can divide the packet into two 2-
However, if the beeswax you have is in the form of random blocks or chunks perhaps
obtained from a local
beekeeper, you will have no option other than to weight the
wax.
Mineral oil can be purchased at your local drug store. The photo at right shows mineral oil sold as “Butcher Block Oil,” available from most woodworking suppliers.
I have no scales!
All the above is well and good if you have a set of scales, but without the scales
you are no better off than before. Fortunately, there is a way get the proportion
of wax to oil without needing the scales. The idea is to measure both the oil and
wax by weight and then use a simple home-
Bwax: 1 oz-
This is simple. Just add 4.4 times as much weight of mineral oil as you have weight of beeswax.
Shop-
You can make a balance for comparing two different weights, and with the proper design,
you can build in the number 4.4 so that the proper ratio is obtained
automatically.
It is not hard to do.
You will need:
A thin strip of wood about 2” wide, and 36” long. The thickness only needs to be enough so that it doesn’t bend a lot when the weights are applied, about 5/16 or 3/8”.
A round pencil or a wooden dowel about 5/16” in diameter. It needs to be round so it can be rolled back and forth a small amount in order to find the balance point of the system.
Two Styrofoam cups or small plastic containers large enough to hold the quantities of mineral oil and beeswax you want to work with.
A small weight: this could be a small block of wood, a pebble, or something similar. The amout of weight required will depend on the weight of the containers you use.
Calibrate the wooden strip.
1. Find the point on the strip of wood where it will balance on the pencil. (The
strip may not have a uniform density along its length.) Draw a line across the strip
at the balance point.
Note: The strip will not come to rest in a stable horizontal position like a real balance. Instead, it will tip to one side or the other until one end of the strip touches the table top. However, when it is “balanced,” you will be able to make it tip to the other side by rolling the pencil ever so slightly (like 1/8”) toward the high side. When it is out of balance, you will have to roll the pencil considerably farther.
2. Make another mark across the strip 3.75” from the line representing the balance
point. Label this line
“Oil.”
3. Move to the other side and make a mark 16.5” from the balance point. Label this line “Wax.” (Note that 16.5 is 4.4 times 3.75.)
Set up the balance.
4. Position the pencil on a table or counter top so that it overhangs the edge about an inch.
Place the strip on the pencil so that the balance point (line near the middle) is exactly over the pencil.
5. Put cups on the strip at the lines “Oil” and “Wax.” Center each cup on the line.
6. Bring the system into balance by adding a weight between the “Oil” c
ontainer
and the end of the strip on that side. Move the weight back and forth until the system
balances with the balance-
Using the Balance
1. Set up the system with empty containers at the “Oil” and “Wax” positions. Place the weight at its designated location.
2. Put the desired amount of beeswax into the wax cup. This will cause the strip to tip toward the wax side.
3. Now, with the oil cup in position on the strip, pour enough mineral oil into the cup to make the system slowly tip from the wax side to the oil side. Verify that the system is in balance. The strip should tip back and forth readily as you roll the pencil back and forth a very small amount (1/8” or less).
The amounts of beeswax and mineral oil in the cups are now in the correct proportion to make the oil and wax finish. Empty each one into the metal container you are going to use for heating the mixture and you will be good to go.
Scale it up.
You can use larger containers for the oil and wax in order to make bigger batches of the finish. However, if you change containers you will have to readjust the weight to bring the system to a balance when the containers are empty (Step 6 above). The containers do not have to be identical.
What did you say?
Of course I know you can buy a scale for a little of nothing! But then you miss the fun of building your own balance.
To make a specified amount of “product:”
At the risk of taking this too far . . . Suppose you want to make a specified amount of the final mixture, say, 4 fluid ounces to fill a certain container you have at hand. The question is, How much oil and how much wax should you use? Here it is:
Weight of Beeswax = Final volume / 5.4 (oz-
Volume of mineral oil = Final volume / 1.23 (fl oz or milliliters)
Example 1: Make 4 fluid ounces of the final mixture.
Weight of Beeswax = 4 fl oz / 5.4 = 0.74 oz-
Volume of mineral oil = 4 fl oz / 1.23 = 3.26 fl oz
Example 2: Make 125 milliters of the final mixture.
Weight of Beeswax = 125 ml / 5.4 = 23 grams
Volume of mineral oil = 125 ml / 1.23 = 102 milliliters
The method using scales: Simply weigh out the calculated amount of beeswax and combine
it with the calculated volume of mineral oil.
The method using the home-
oil to the “oil cup.” Then add beeswax to the “wax cup” until the
system balances. Combine the two in the melting pot and you will be ready to “cook
the brew.”
******************
A few weight and volume equivalents:
1 pound = 16 oz-
1 oz-
1 fluid ounce (volume) = 29.55 milliliters (ml)
1 cup = 4 fluid ounces = 118.2 milliliters
1 pint = 2 cups = 16 fluid ounces = 472.8 milliliters
1 milliliter of water weights 1 gram.
1 milliliter of mineral oil weights 0.9 grams.*
*Varies somewhat depending upon the exact formulation.