-- Last Updated: Nov-07-12 4:41 PM EST --
I don't think that oil finishes penetrate the wood to any significant extent and yes, the finished part of the wood is easily scratched off, perhaps more easily than a varnish or polyurethane finish.
I do find, however, that while sharing similarities, different oil products handle quite differently and produce significantly different results.
I think polyurethane or varnish is a terrific finish for wood that is not subject to much abrasion but is subject to long periods of continuous UV exposure, such as the deck of a wooden motorboat. Oil finishes on wood that is left outdoors sometimes attracts dust and dirt and greys. Most canoes are not left outside for very long periods of time, however.
There are a lot of folks who prefer using oil finishes on the gunwales of their canoes, if not on all the wood trim. Are we all dupes of a marketing ploy?
I think those who prefer an oil finish accept that the finish will need to be renewed more frequently than a varnish or polyurethane finish but choose oil because of the ease of application. Oil finishes, unlike varnish, are rather indifferent to the method of application. Varnish needs to be applied carefully to avoid sags and runs and for best results should be wet-sanded between coats. The wet varnish seems to attract every gnat and bug in the neighborhood while it is drying. And it is difficult, if not impossible to apply more than one coat per day.
Even for an oil finish with a rather involved application process like Deks D1, it is possible to apply 6 coats to a canoe's gunwales in an
afternoon. Applying 6 coats of varnish is a week long task. Once the initial application of the oil finish is done, touch up is also much quicker and easier than for a bright finish.
Another reason some prefer oil finished gunwales is simply the way they look, which is very significantly different from a bright finish.
It seems that this topic has about been beaten to death, but if anyone really wants additional opinions regarding oil finishes vs bright finishes, go on over to the wooden boat forum. Wooden boat owners tend to be pretty fussy about their wood. Here is a thread regarding Deks and other oil finishes: http://forum.woodenboat.com/showthread.php?4587-Oil-finishes-Deks-Olje&highlight=Deks+Olje
Not everyone there is a fan of oil finishes but this post pretty much mirrors my experience with Deks Olje:
" Deks #1 is a true matte, rich-looking oil finish. I don't know what's in it in terms of UV absorbers, but as long as it's maintained it doesn't seem to look much different as time goes by. I'm not sure I'd leave a boat in the water or out in the weather with only Deks #1 as a protector, but for dinghies or small boats that get covered storage, it holds up quite well, as will a lot of other coatings.
The ease of application, fast initial application and drying times compared to many other oil products (it's not still sticky two weeks after application, unlike some oils) easy touch-ups and that nice looking subtle finish are what I have always liked about it. The key to getting lasting results seems to be learning to apply a fresh coat before it starts looking like it needs it. That way you don't need to go in and sand any areas that have dirt ground into them.
Since I tend to approach re-varnishing as an unwanted chore, the fact that Deks is easy and quick to re-apply tends to simplify the process to the point where I don't put it off until the last possible moment. I've also used #1 as a base layer for varnish a couple times, instead of priming with diluted varnish. I don't know what the chemistry involved is or whether it's a good idea or not, but it seemed to hold up pretty well.
They used to run an ad in WB for Deks Olje showing one of Jay Benford's boats (named Sunrise?? and 34' sticks in my mind, but may not be accurate) that was finished bright with Deks #1 and #2. It was lovely and lived in the Pacific Northwest, so the stuff must work OK out on a mooring as long as it's maintained. I don't think it will ever put the varnish makers out of business and am not claiming that it holds up better, or even as well as a good varnish job, but for classy-looking, easy to maintain small boats I really like the stuff. "