Am I crazy? I’ve been sanding my black walnut projects starting with 120 grit and progressing up to 1500 grit. The finish at this point is akin to glass. You can see your reflection in it. I use a 1/4 sheet random orbit sander to avoid capell-tunnel-syndrome.
The question is “have I exceeded the point-of-no-return” for finish quality? Most people talk about going up to 220 or 320 grit before applying their chosen finish. What are the issues associated with sanding to 1500 grit or even beyond?
P.S. I use Fornbey’s Tung Oil wiped on in 4-6 coats depending on my patients; sanded between coats with 3M gray pad. The resulting finish has gotten nothing but raved reviews from my laymen friends. But what do you experts have to said about sanding to the max?
MikeC at Pine Cabin Workshop
Replies
I'm no expert but here is what I do.
If I'm staining with a top coat I stop at 120/150. With an oil finish on walnut I've ben known to go to 220.
When I do an oil finish I might put on 4 or 5 coats and only sand the last coat with wet/dry 400 as I put on the coat, it makes a bit of slurry and fills the grain to .
Jeff in so cal
70 f---45%
Mike, they make 2000 3000 and 4000, Perhaps you got to the point of,so fine, the results were undetectable. Ron
MikeC - I sand as little as possible and always get a silky smooth finish. It's because I always apply a film forming finish (varnish, lacquer, shellac, waterborn, etc.). The finish builds a layer on top of the wood and when people feel the wood, they're actually feeling the film finish. There's no need to sand the wood beyond the grit needed for the finish to fill the scratch marks and form a level surface. Personally, I never sand the wood beyond 150 grit.
I generally sand the first coat or two of finish back to achieve a smooth, level surface, then complete the finish on top of this base. To get a silky smooth finish, I sand the next to the last coat with a fine abrasive so the the final coat flows out like glass. The key is to make sure the scratch marks in the next to the last coat are fine enough for the last coat to flow level.
Sanding between coats with 320 grit sandpaper is often recommended. You use gray scotchbrite which is equivalent to 360 grit (a LOT more coarse than the 1500 you used on the wood). Since you can only feel the finish, not the wood under the finish, then it's clear that a surface sanded with 360 grit feels great. There is a difference in the texture of the scratch created by sandpaper and scotchbrite - so a finer sandpaper would be needed to get the same effect.
Formby's Tung Oil finish is a varnish thinned for wipe-on application. It builds a film on top of the wood. The more coats, the thicker the film.
Paul
F'burg, VA
I'm with you, Mike. The surface of the wood doesn't even start to get interesting until you get to somewhere around 400, depending on how hard the wood is. And if you think it's pretty at 1500, there's another threshold at about 6000. The scratches become so small that the surface goes optical. Not only can you see your face in it, you can see the details on your face. No plane or scraper sharpened by mortal hands can even come close. MicroMesh makes grits up to 12,000. Most of the samples I sanded to 12,000 looked like they had already been finished. The Macassar Ebony was the most dramatic look.
Now as to how much of that work is visible after finishing, I don't know, but it would be easy enough to test. Certainly easier for you with the ROS that for me, still stuck at hand sanding. Just make up a series of samples, stopping after each grit, then finish them and see if you or anybody else can tell the difference, or at which grit you stop seeing any difference.
Mike, is it what you want? If so, then thats what you need to do. I think I know what you are trying to do and admit that I have tried it myself but it became far to tedious for me to continue. Polishing wood is not a new thing but some of us have given it up due to the need for the all mighty dollar.
Please note all... I didnt say all of us gave it up, just some of us and I include myslef in the "some" group.
Edited 12/5/2002 11:43:50 PM ET by no one
mike,
I think the only issues with sanding to excess involves the stain and the porosity of the wood. I have sanded many times to 400 grit in the belief that it would help control bloching of the wood with the waterbased stain...it hasen't always worked.
If the wood is porous, sanding to excess helps a bit, but fillers are needed to achieve the glass like finish.
That's all I know Mike and it may be wrong. I read so many conflicting protocols..or approaches that arn't available to me (e.g. sprayers, spray booths). But, if you want to have some real fun put a chuck of wood on a lathe...I made some simple maple rolling pins...2000 grit and finished up with sawdust. That's it..no other finishes..still looks beautiful
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