re: Lets Talk "oil finishes"

When posting my reply, I neglected to mention hardening finishes, including oils, will penetrate, if keep them wet. It’s only after you allow them to start hardening that you seal the wood surface against future applications, other than for build coats.

Lanwater, on oils, there is a lot of information out there. Basically, it starts off with the difference between hardening (e.g., walnut, tung, boiled (not really) linseed oil, etc.) and non hardening oils (e.g., Quakerstate 20 weight, mineral oil, etc.).

From there, it gets into oil based finishes like Varithane and so on. Back in the day, these were called long oil or short oil finishes. That was just a way of saying they went long on the oil, that is, added more, or went short on it.

Long oil finishes are what most marine type finishes are. By adding more oil, the final finish is more flexible, so tolerates shifts due to moisture content changes. The down side is, they are less durable.

Of course, additives can make all the difference. For example, most poly finishes contain resins that contribute to their durability.

Now, jump to names and claims of finishes. As most know, rare is the tung oil finish that actually contains tung oil. So to it goes with Danish oil or Teak oil.

Instead, the “tung oil finish,” unless it says “pure tung oil,” or “100% tung oil” is just boiled linseed oil with some resin and thinner added. You get the same stuff by thinning a can of your favorite oil based finish about fifty or more percent with paint thinner, turpentine or naphtha.

As to Danish oil, just like that no babies were used in its making. . . . And how many teak trees did the manufacture squeeze to get that relatively inexpensive teak oil?

Usually, the reason people have luck with these kinds of finishes is, they tend, that is maintain the wood project regularly with it. As it dulls or weathers, they apply another light coat, which fills and seals cracks and splits in the previous finish.

All the exterior finishes use some kind of U.V. protectant. If memory serves, titanium oxide is common. These additives reflect the sun’s rays back, away from the wood.