Wet Sanding

[Dave Fritz]

I like to wet sand walnut due to it's open grain. I usually finish bowls with tung oil so I use thinned tung oil for the wet sanding. Now I'd like to finish a pepper mill with poly and wonder what I could use to wet sand with? Thanks

 

[Marc Banka]

Could you please explain the connection between open grain wood and wet sanding? What is different, better?
Thanks!

 

[robo hippy]

You can wet sand with any oil, and/or water. Of course if it is on the lathe, you want low speeds so you don't end up wearing most of the finish.

As for open grained woods like walnut or any of the red/black oaks, they have very open pores, and can 'leak'. If you wet sand, more so with finer grits, the slurry mix will plug the holes. I will never forget seeing Roy Underhill take a split billet of red oak and stick it into a bucket of water and blow bubbles out the end.....

robo hippy

 

[Doug Freeman]

I wet sand with poly. Thin it 1:1 with ms and go. Flood it on, keep adding until it stops soaking in so much, then sand. If it gets too thick, add ms or the mix. Wipe it down when done, just like tung oil. You may find you like working with the poly better than tung oil, I did. Poly does not have to used as a film forming finish, just let it soak in and wipe it off like an oil. It dries faster and offers significant structural strength to the wood vs an oil.

 

[Dave Fritz]

Could you please explain the connection between open grain wood and wet sanding? What is different, better?
Thanks!

In my opinion I get a much smoother finish. Buffing doesn't leave residue in the open pours. White diamond especially will leave white spots. A friend gave my wife a French rolling pin made of or walnut that he finished with Waterlox, then buffed. It had many small white dots that he didn't know where they came from. He found out. I now use vonex instead of white diamond.

 

[Marc Banka]

Fascinating.

I had only known of using something like water to keep the abrasive clean and sharp. Don’t see a big need for that-- didn’t find it worth the mess. What you all are describing is a whole other thing.

I have a good number of Oak bowl blanks ready for second turning. Might be a good time to try thinned oil or varnish as Doug explained. I’ve been thinking that for some bowls, especially those that will be handled, but not used for everyday food service, a finish (and method) that toughens the fibers, doesn’t fingerprint and smudge as easily as oil/wax, and isn’t a film finish could be a nice option.

Follow up questions: Assuming dry sanding, I believe it’s customary to clear the pores of sanding dust before finishing. I though the dust lowered the contrast/definition and muddied the color, but with wet sanding one is purposely doing just that. I’m wondering why the dichotomy? I suppose my question is largely rhetorical but appreciate comments.

So, one would start by sanding dry up to grit ? then wet sand (blo and ms) to what, 600, higher?

I‘ll do my experimenting per usual, but appreciate not having to start from zero

 

[Dave Fritz]

Marc, I usually dry sand up to 220, then switch to wet sanding with 220, 340, and 400. I've never gone any higher. I do use a dry towel after each grit to remove the sanding sludge between each grit. I use a pet training pad under the project because it can get messy. I've found by wet sanding walnut I actually enhance the figure. Maybe I'm seeing it because I want to see it. I've never really compared the two methods side by side.

 

[Dave Fritz]

I wet sand with poly. Thin it 1:1 with ms and go. Flood it on, keep adding until it stops soaking in so much, then sand. If it gets too thick, add ms or the mix. Wipe it down when done, just like tung oil. You may find you like working with the poly better than tung oil, I did. Poly does not have to used as a film forming finish, just let it soak in and wipe it off like an oil. It dries faster and offers significant structural strength to the wood vs an oil.

Doug, do you understand you to suggest it would be ok to wet sand with poly and when dry finish with tung oil? I will definitely try wet sanding with the poly mix as you suggest. I wonder if urethane could be substituted for poly? Thanks for the information.

 

[Dave Hulett]

In my opinion I get a much smoother finish. Buffing doesn't leave residue in the open pours. White diamond especially will leave white spots. A friend gave my wife a French rolling pin made of or walnut that he finished with Waterlox, then buffed. It had many small white dots that he didn't know where they came from. He found out. I now use vonex instead of white diamond.

I also made the conversion to Vonex. Walnut in particular was a big problem with the white spotting. I tried using several kinds of sanding sealers but found the finish wound up to glossy. Vonex seems to be much better.

As to your orginal question I have wet sanded using my preferred mix of 50/50 MS to Poly and it works. the thinned mixture fills in the pores.

 

[Garry Durfey]

I like wet sanding with Walnut Oil after dry sanding up through 220 like someone else said.

 

[Dave Fritz]

Gary, would you put poly over that?

 

[Doug Freeman]

Doug, do you understand you to suggest it would be ok to wet sand with poly and when dry finish with tung oil? I will definitely try wet sanding with the poly mix as you suggest. I wonder if urethane could be substituted for poly? Thanks for the information.

Urethane vs poly - dont be fooled by the mktg, they are the same for finishing, particularly when not building up a film finish. From what I can tell in my experiments there’s no difference with building a film either.

Yes you could put tung oil over the poly (lightly sand the dry finish) but why? Tung oil is not a film finish, it will be soft and gummy.

Make a few simple turnings to test out the poly. Wet sand the initial coat, let dry to touch. You may find dry slurry you didnt wipe off, wet sand it off, let dry. From there, let cure and buff, or add more “wipe off” coats, or add film build coats. FYI I use semi gloss poly (minwax) so that negative grain or holes do not appear glossy.

The final gloss level of the surface is determined by the final dry wood sanding grit, and then the level it is buffed to. Always experiment with throwaway pieces. Once perfected use on a keeper.

 

[Garry Durfey]

Gary, would you put poly over that?

My understanding is yes. Walnut oil drys, then you can put the other finishes over it.