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Well, I started wet sanding #6 last weekend.
I sanded (Nitro) with 600 leaving just a bit of orange peel. Looked great.
Next day, I sanded with 1000.
Like a dummy, I was not vigilant in keeping the water wiped off.
Water seeped into holes and glue joints swelling the wood and buckling the finish.
I used Titebond 1 which is not waterproof.
After drying out for a day, it's not too bad. First time I have had this happen.
I read that Mineral Sprits can be used as a lubricant, but I don't want flammable rags laying around.
Other than a lesson learned, are there alternates to using water or perhaps a better technique?
Thanks,
Dan

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I use olive oil for small repairs and for a bit of leveling at the end of a FP. It's a PITA on a whole guitar but shellac and water are a lousy combo. Paraffin oil would works just as well with paper as it does with rotten stone. Almost any liquid that will not harm the finish would likely work, some better than others. All have draw backs, oils can contaminate glue surfaces at dovetails. Solvents splashed inside the box can leave freckles and stains. No matter what you use for lube you must use caution. So, yes, I just use water.

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Brian

You never know what you are capable of until you actually try.

https://www.howardguitarsdelaware.com/

I haven't tried it but I heard you can put a small amount of dish soap in the water and it works good.

I won't use water without it, water by itself creates a suction that sticks the sandpaper down to the surface, soap seems to help with that. I do prefer mineral spirits over naphtha as it doesn't really evaporate like naphtha does. You do have to mind your oily rags but that's just good shop protocol really. Just hang them over the edge of your bench or the lip of a garbage can, unfolded and let them dry overnight OR get a bucket of water to throw them into. Make sure you dunk them all the way in the water, and finally don't leave them sitting by a heat source or in the sun.

Painting the inside of the holes with lacquer using an artists brush helps on tuner holes and pickup cavities but not so good for small holes. Even doing that, I've had water damage with tuner holes in holly veneer headstocks keeping no visible amount of water on the surface. I really dislike the stench of odorless mineral spirits and it doesn't work nearly as well as water.

So I've gone to total dry sanding my nitro finishes. I use my Festool RO125 with Granat 600/800 for the large areas and regular 3m gold 216U 400-800 for areas that can't be done with the RO. The Granat is a film backed abrasive and is probably similar to the 3m micron film backed and Mirka polarstar used in bodyshops. The 1500 Granat is too fine and loads up but the 800 works really well. The trade off is I need to start buffing with coarse compound but I skip a lot of fine sanding. Seems to be a good trade-off.

Thanks fellows,
I do use dish soap in the water. I did pre-paint the holes with lacquer.
I'll remember to slow down and keep wiping.
Only the control holes look bad after drying. I'll sand and shoot some more nitro on the top.
Dan

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Naptha diffuses readily through lipid bi-layers, and causes neurological damage. I definitely wouldn't wet sand with it.

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Old growth, shmold growth!