Wet Sanding considerations

[Steven Forrest]

Hi, all,

I am trying to incorporate more wet sanding into my routine, but I'm confused about sequencing. At what point is wet sanding most effective? Early on/coarse grits? Later on/fine grits? Also, I'm wondering about the wetting agent. If my final finish is going to be oil (with or without wax), say, then it's obviously okay to wet sand with oil. But if my final finish is going to be, say, Seal a Cell or some other oil/poly hybrid, I'm nervous about wet sanding with simple oil before that. So I guess my question boils down to, what would be the preferred wet sanding agent before this or that final finish? Thanks for any wisdom or guidance you might offer.

 

[Bill Boehme]

I wet sand the finish, but never bare wood. I wet sand lacquer or CA finishes using water and frequently flush the swarf from the paper with running water. I only do this after the surface has been thoroughly sealed with five or six coats. I only use very fine grits like 600 and up to 12,000 (Micromesh). My goal for the coarsest grit is to completely level the finish so that there aren't any shiny spots. After that, the finer grits are to bring the finish to the desired level of gloss. Because water will cause bare wood to pucker up is important that I don't sand through the finish.

Some people sand bare wood using linseed oil to flush the surface. I don't like it because sanding grit gets embedded in the wood along with sanding dust. Just my opinion, but I think that sanding bare wood with oil masks some of the luster of the wood. I am definitely not a fan of sanding with wax, but that's just my 2¢.

I dry sand bare wood up to 400 grit.

 

[Ed Davidson]

I also never wet sand bare wood. Wet sanding is normally used with acrylics, stabilized (plasticized) woods, epoxy resin and polymer clay. I'll normally dry sand these materials up to 600, then progress through the wet sanding grits up to 4000, followed with a light Beall buff.

 

[Michael Nathal]

I frequently wet sand bare wood with walnut oil. After curing (which can take a long time) I sometimes go directly to Beall buffing. But i also put coats of oil based finishes on top -- Danish oil, WOP have worked for me. After a few coats it is ready for buffing. Wet sanding the film finish with water between coats is a good idea.

 

[Doug Freeman]

I use poly quite a bit, but more like blo or danish oil - thinned 1:1, let soak and keep wet 5-10 min, wipe off.

After 2-3 coats I wet sand using mineral spirits or poly, starting at 600-1000 gr, depending on the surface, and go up thru P2000 gr sandpaper. I want a slurry to fill grain. Then buff with white polish pads from woodnwonders.

If its a fully filled finish like ca or lacquer, I use soapy water if I can but if wood will get wet I use ms. Start at p400-600 to level, then up to p2000 and finish with auto buffing compounds.

 

[Emiliano Achaval]

I have been wet sanding my boxes, only with the final 320 or 400 grit. Not sure if a sanding wax qualifies as "wet" sanding. Definitely cuts the dust down and get a nice finish.

 

[Steven Forrest]

Thanks, folks. It sounds like the consensus is : wet sand for the last coat of already finished wood, or wet sand with the product that will become the last coat. Oil based finish can go on after wet sanding with oil. Wet sanding in general for later/finer sanding, not early/coarse sanding. Further comments cheerfully accepted.

 

[Dan Stevenson]

I'm doing lots of Norfolk translucent pieces now that are cut thin and dry sanded to 220 or so then begin the soaking process in BLO/Mineral Spirits. After each day-long soak, and while still dripping I quickly wet sand the piece with a progressively finer grit starting at 220 and ultimately 3000 towards the finished soaking/drying rotations. I can tell you from experience oiling or wet sanding with heavier grits doesn't do a heck of a lot more than load up the sandpaper with oily fibers and works much better for me, dry.