Since the mid 1960’s I’ve been using Watco Danish Oil for finishing almost everything. I built a house in 1980 and all of the cabinetry was finished with that, followed by a 3 part mixture of boiled linseed oil, polyurethane, and turpentine I learned about at San Francisco State. That was demonstrated by Arthur Espenet Carpenter and used by many students in the Design and Industry department. However; I’ve lamented many times in these blogs about how the EPA standards have forced changes in the formulation of the Watco oil. As a comparison, any of you work on cars and been around long enough to remember using gasoline to clean parts before it became unleaded? Old school gas would completely evaporate and leave a clean surface, unleaded on the other hand leaves a film. You can feel it on your hands too, why? Probably to eliminate those VOC’s escaping into the atmosphere. I think the same has happened with finishing products. The smell, feel, and working properties of Watco are just not the same.
So, enter a product made in Germany by a company called OSMO. I first learned about this finish from issue 262 of Fine Woodworking Magazine, here’s a LINK to that article but you may need to be a member to read it in its entirety. It’s available from World Class Supply and I use their #3054 which is a matte finish. It’s available too from Amazon but I still like dealing with independents whenever I can. It’s advertised as an eco friendly product made with all natural materials. I first tried this product on a sliding door commission and intended to explain the process but forgot! Let me do that now on the bookcase.
For starters, the OSMO is quite thick and the directions say to apply a thin coat. This was accomplished with a chip brush and completely wiped off after soaking into the surface for about 30 minutes — like Watco this is an important step! Any finish left in corners will get gummy. The Watco process calls for sanding the top coat in with successive grits of wet/dry paper beginning with 320 and working up to 600 or more. With the OSMO being so thick that didn’t seem to work well so only used 320 with a flat, rubber sanding block. The second thin coat was brushed on, allowed to soak into the surface for about 10 minutes and then sanded with the 320. If it started to drag I would put some more finish directly on the sanding block. After completely wiping dry I’m happy with the hand rubbed luster on the piece. According to the manufacturers information this product is more resistant to moisture and stains than Watco is — time will tell but so far I’m happy!
I know it’s really difficult to show the results in a photograph but here’s the finished bookcase. The solid wood face frame and side have been sanded with the 320 grit. The shelves and back are made of plywood and I didn’t dare use sandpaper on the tissue thin veneers used these days (ugh!) so they were finished the same way but with a white scotch pad instead. Time consuming process but in my opinion, it’s worth it.