I made a really nice solid walnut desk here at Asmbly last week and I’ve got it sanded and smooth. I’m trying to decide how to finish it and I see lots of conflicting advice on the internet.
Should I use a grain filler? Should I use a poly or a wax product? I see lots of glowing praise for Rubio monocoat but it’s quite pricey to get all their recommended products. I want a natural looking finish that will stand up to me using it as a desk.
Rubio is not as expensive as it first looks, and the effort that it saves is well worth it. It depends on the finish you want. If you want a gloss or semi gloss finish, no Rubio. But film finishes require a finer sanding, then sanding between coats. Rubio, just the one coat, and it’s spot repairable. Almost a matte finish.
It doesn’t take much Rubio, though an entire desk will take more that one of the sample bottles. 2 or 3 might do it, but I haven’t seen the desk. Those are $5 each at Woodcraft.
I’m about to start experimenting with Odie’s Oil. Also pricey, but a little goes a long way. And there are methods posted to body the surface sheen.
The Stumpy Nubs YouTube channel has loads of information on various finishes - and their explanations give a pretty good set of pros and cons for all sorts of options
Personally, I would not grain fill walnut. No need and the resultant color will look strange. For a natural finish, I agree with Charlie on Rubio. I finished this walnut table in Rubio pure. It’s a matte finish but you can buff it to give it a bit more sheen. Osmo is also a good oil wax finish that gives a bit more sheen than Rubio, although application is slightly more involved. Both are extremely durable (often used on flooring) and can be spot repaired. Cost per ounce is higher than a varnish or poly, but the time savings is significant as it’s a one and done finish. No need to get the cleaners, soaps, etc. Just the finish should suffice.
I absolutely agree with you! Definitely do not use a grain filler on walnut- typically you only use a grain filler on open grain wood when you do not want to feel the natural grain of the wood.
Also the Rubio Mono provides a very nice and durable finish, is user friendly, easily repaired if/when necessary and in my experience, more economical than poly finishes. One coat of Rubio vs several coats of poly that require light sanding in between coats and days of waiting.
This is good tutorial on Armor-Seal.
My second favorite part of this video is watching Matt’s grooming transformation. I’m always surprised by how many viewers miss this.
I’ve used osmo thin, regular, and Rubio. I prefer the rubio now. I would say using the white and purple 3m pads to buff it on is very helpful. And although the directions say you only need one coat, I usually put two on my table tops. The first coat I use a hard plastic “bondo” type credit card thingie (that is for sure the technical term 
) and work it into the wood, then I use a buffing pad to buff it into the table. It is important to wipe as much off of the table as possible. After it dries, I go back with my buffer and the purple 3m and scuff the table, I blow it off then wipe it with a rag and apply a second coat of rubio. This time I use the white 3m pad and much less rubio. I hardly put any on at all just enough to wet the surface and buff it in. I get a slightly better sheen doing it this way.
I used clear wood grain filler and shellac on the walnut desk I made awhile back, I think the post is somewhere here. I may have also used arm r seal? It has been awhile so Im not entirely certain.
Personally I really like the result, but the grain filler was honestly a pain to use.
