Wet sanding

[Alan Weinberg]

I gave read about wet sanding but don’t quite understand. I’ve used water to raise grain and I’ve sanded after oiling when the oil (and sunlight) show me previously unnoticed scratches. I tried sanding a piece I had soaked in water and detergent and it quickly and repeatedly clogged the sandpaper. What’s the technique and what are the advantages of wet sanding over just sanding? Mineral spirits, walnut oil, poly, after 220 grit—what are the reasons and technique?

 

[Randy Anderson]

Alan, I don't wet sand but noticed a couple of things in your thread to comment on. I sometimes soak pieces in a water/detergent solution to make final sanding easier but - I do that right after turning green, soak for 24 hours, rinse then put up to dry just as I would any other piece. I don't sand them right after soaking. I do spray with water sometimes while sanding, usually between 180 and 240 but still, I wait for the surface to dry before I start sanding. I've tried wet sanding with oil at about 320/400 grit and found the mess wasn't worth the effort. My main wipe down to find scratches, tool marks or areas that don't look right is plain mineral spirits. Dries quick, shows a good approximation of what the finish surface will look like and doesn't raise the grain.

I often do a quick sand while green and on the lathe with open weave 80 grit to give a cleaner surface for when I do sand later on when the piece is dry. It clogs but can easily rinse it out and keep going.

 

[Alan Weinberg]

e

then put up to dry

that’s what I didn’t do—tried sanding “wet” right after pulling from solution. I took the word literally. Thanks.

 

[Randy Anderson]

Alan, I don't soak many things but find it does help especially on bradford pear and sometimes black cherry. I really only use it when experience is that the outer surface can develop what I call a tough brown oxidation layer that can be a real challenge to get off. Bradford pear is the worst for me but not always. Cherry can be sometimes but again, not always. Never figured out the science or timing when cut down to understand it fully. I just finished two black cherry live edge bowls, didn't soak them and they sanded fine. Of course the next ones I do I'll probably wish I had soaked them. Some folks soak a lot of what they turn as normal routine. My experience is that it does help the initial sanding process but, let if fully dry before sanding.

Also, I buy clear liquid dishwashing soap online. If you look at the options you can get large jugs of it for a reasonable price. Much better than buying at the store.

 

[Darryl Fective]

Soggy wet wood will clog paper when sanded, but if you wet the paper and the wood, the water sort of lubricates the process and creates a slurry of water and dust. It rinses from the paper easily and with no airborne dust.

 

[Alan Weinberg]

but if you wet the paper and the wood,

very helpful. My wood was too soggy.

 

[robo hippy]

Some will only wet sand, and use their finish oil. I don't. One reason is that wet sanding with the lower grits can fill in your holes and tool marks so you don't see them till the piece is done. Another reason is the mess. Another reason is that it just seems easier to sand out a bowl when the wood is dry. I have never turned Norfolk Island pine, or the other similar woods with the radiating branches. The resin in those woods can really gunk up your abrasives instantly. That is what lead Ron Kent to the LDD (liquid dishwashing detergent) soak. Not sure if he sprayed the pieces with soapy water or finish as he sanded them out.

robo hippy

 

[Darryl Fective]

I prefer to sand my pieces after they have dried. (at least on the surface) Then I apply multiple coats of thinned poly, and after they start to build up a little bit, I sand in between coats. Since it's mostly poly and not much wood, I will usually wet sand, either in the shop with a spray bottle, or at home in our kitchen sink. (yes, I have a very tolerant and wonderful wife)

 

[Alan Weinberg]

I buy clear liquid dishwashing soap online. If you look at the options you can get large jugs of it for a reasonable price.

5 gallon jugs at Smart&Final.