Sanding Wet Wood

Photo: Sanding Wet Wood 1
Old school wisdom says you can’t sand wet wood. i.e. something you turned out of a fresh log. You have to wait for the wood to dry out, then sand it.

If you try to sand with old school PAPER backed sandpaper the wood turns to mush and almost immediately clogs your sandpaper. You can’t wash off paper backed sandpaper with water. The paper just turns to mush.

Red Siasoft and Mirka Autonet are game changers. When the wood turns to mush and clogs up Red Siasoft you can do one of two things.

Wet Sand

You can wet sand with Red Siasoft. Get a bucket of water. Dip the Siasoft in the water when it jams up with mush to remove the mush. Then just keep dipping and sanding. i.e. like wet sanding while painting a car. See my “Red Siasoft Sandpaper” blog entry.

Beware! The wood you are sanding will become sopping wet!

Long ago, I did a lot of wet sanding. I no longer do it. Because waiting for the wood to dry out before you can apply a finish is a pain! Often you need to sand the wood again after it dries out because water raises the grain. Or the wood turned gray, etc. You have to do the dry sanding off the lathe, after the wood shape has distorted during drying. Ugg!

The next method now works better for me.

Friction Dry with Siasoft then Sand with Autonet

    Photo: Sanding Wet Wood 2

  1. Protect any fine details like the edge of a rim with 2 layers of masking tape.
  2. Use multiple pieces of 80 grit Red Siasoft to dry out the wood via friction.

    See my “Red Siasoft Sandpaper” blog entry.

    Beware! To much friction will create to much heat and lead to cracks. This generally is not a problem. Because heating up wet wood is not easy.

    Photo: Sanding Wet Wood 3Keep switching to new chucks of Red Siasoft when a chuck jams up with wood mush. I often end up using 10 chunks or more. See photo.

    Later, you can just wash off all the wood mush with some water. DRY OUT the sandpaper and use it again.

    Hint, you can speed up drying out the Siasoft by pressing the pads together between two pieces of plywood in a vise.

    Photo: Sanding Wet Wood 4

  3. When time permits I will often air dry the wood now or before the first step.

    I set up 2 small box fans (computer equipment cooling fans) that blow LOW velocity air over my work while still mounted on the lathe. See photo.

    I then wait several hours for things to dry while I go to lunch, etc. I don’t want my work to crack. Thus I use cool LOW velocity air. Dry it slow. With the lathe off to save electricity.

    If the piece warps to much then I will not be able to sand it with the lathe running. Thus I limit my fan drying to a few hours and check it from time to time for warping.

    The fans I use are old surplus, high quality “Comair Rotron Tarzan TN3A3″ fans. 230 volts, 340 cfm, 7″ by 7″ by 4”. I run them at 1/2 speed on 110 volts. Thus they are 170 cfm and really quiet.

    Photo: Sanding Wet Wood 5You can get something similar, but smaller, nosier?, and less cfm on Amazon “AC Infinity AXIAL LS1238, Quiet Muffin Fan, 120V AC 120mm x 38mm Low Speed”. $17 on 3/20/2020.

    If you want a new fan more like mine you could try something like an Orion OA172SAP-11-2TB, # 1053-1039-ND, 115v, 170cfm, 42db, $42 on 3/20/2020.

    Photo: Sanding Wet Wood 6

  4. When the wood gets close to being dry. I switch to power sanding with Mirka Autonet Mesh discs. I sand with the Autonet 80, 120, 180, and 240.

    See my “Mirka Autonet Sandpaper” blog entry.

  5. Remove any masking tape from fine details.
  6. Sand the fine details with small chunks of old fashion sandpaper and/or Autonet.

    See my Klingspor Sandpaper Rolls” bog entry.
    Photo: Sanding Wet Wood 7

  7. I put a finish on right away. One or two coats of Miniwax brand gloss spray on polyurethane.

    This is really just a holding coat. Not the finial finish. I don’t want have go back later and sand again. Thus I want to protect the surface while I am waiting for the wood to completely air dry. Stop the grain from raising, etc.

    The wet wood and end grain will suck up the poly. I wait 10 minutes and then wipe off any excess.

    I use spray on poly, rather than brush on poly, because the spray on poly is thinner and thus soaks in easier.

  8. Wrap the piece in brown paper and put it in a cool place to dry for 2-3 weeks.

    You want the piece to dry nice and slow from the INSIDE out to avoid cracks. The coat of finish on the outside is going to force drying from the inside first. Wrapping in brown paper is going to slow the rate of drying from the inside.

    The theory is that when wood dries the cell walls in the wood shrink when water is removed from the cell. If the cells on the outside of a piece dry first, before the ones on the inside, then you get cracks on the outside. Because the cells on the outside can’t shrink down. The cells on the inside are still full of water and thus can not shrink. i.e. air spaces (cracks) have to develop between the cells on the outside when they shrink. If you can force wood to dry on the inside first (from the inside to outside) then you minimize problems with cracks.

  9. Spray on a finial finish.

    After the piece has completely dried for 2-3 weeks. I remove any poly on the surface with a 360 or 500 grit Abralon Pad. Then spray on one or two more coats of poly.

    See my “Abralon Sanding Pads” blog entry. And my “Great Polyurethante Finishes” blog entry.

Sanding Cheat Sheet

Photo: Carl's Sanding Cheat Sheet

Check out my Sanding Cheat Sheet. It ties all of my sanding blog entries together. Wet Wood? Already Finished? Spindle Turning? Bowl or Hollow Form? Then use …

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