Wet sanding questions

[Roger Chandler]

I roughed out a calabash bowl back in December, and now have finish turned it. It is from a large hunk of Bradford pear......it lost almost 4 lbs. of moisture while it was bagged up.......the roughout weighed right a 13 lbs at first! Whopper piece of Bradford pear, and laden with moisture for sure. Here is a pic of the roughout I posted back last December.



I have dry sanded at 80 grit and 120, but no matter what technique I used on the turning, whether shear cutting, shear scraping and such, I still have a bit of tear out in the end grain. I feel like I should not progress to any higher grit, but begin a wet sanding sequence in order to clean up the tearout.

Now, some questions......since I am not wanting to put a walnut oil finish on this , and perhaps [not decided yet] a WOP finish, should I just wet sand with mineral spirits? I was reading on the can of Minwax WOP that it should not be thinned........would you thin some WOP and then wet sand with that combo if you were going to use WOP, or would you use some type of oil finish that is thinned to wet sand, then when dry apply the WOP? I have on hand both WOP and Antique Oil finishes, plus Doctors Woodshop and Mahoney's walnut oil.

So, mineral spirits alone, thinned WOP, or thinned AO or Walnut oil for wet sanding? Is it okay to put WOP over a wet sanded surface with thinned oil finish? I also have a can of Minwax tung oil, but understand that some say it is not a true tung oil.

Some of you finish guru's might be able to help me here..........calling John Keeton, Pashun or any others who might have solid answers? Thanks to all who try to help me with this!

[Bob Bouis]

You didn't mention it, but boiled linseed oil puts nice color into bradford pear and dries fast so you can coat it with polyurethane later if that's what you want to do.

[John Sincerbeaux]

Assuming the piece is totally dry (I use a moisture meter) and you re-turned the piece to its final shape and thickness. If your tooling could not remove tearout, then like you said, you just have to sand it out. I would power sand starting at least 80, maybe 60 all the way up to180. I use a variable speed angle grinder with 4" discs (made for stone, tile bull nosing). Then I would switch to ROS sander and sand to 400 for lacquer or 800 for a oil/varnish finish.
I personally don't understand the "wet sanding" you are talking about? not sure how wet sanding would ever take out tear out? The only time I ever wetsand, is to "level" a sprayed on finish prior to polishing. I know some guys will "pore-fill" by wet sanding creating a slurry, but to get rid of tearout, you got to sand to the bottom of the tear out pits.
Just the way I do it😀

[Roger Chandler]

Assuming the piece is totally dry (I use a moisture meter) and you re-turned the piece to its final shape and thickness. If your tooling could not remove tearout, then like you said, you just have to sand it out. I would power sand starting at least 80, maybe 60 all the way up to180. I use a variable speed angle grinder with 4" discs (made for stone, tile bull nosing). Then I would switch to ROS sander and sand to 400 for lacquer or 800 for a oil/varnish finish.
I personally don't understand the "wet sanding" you are talking about? not sure how wet sanding would ever take out tear out? The only time I ever wetsand, is to "level" a sprayed on finish prior to polishing. I know some guys will "pore-fill" by wet sanding creating a slurry, but to get rid of tearout, you got to sand to the bottom of the tear out pits.
Just the way I do it

Thanks John for your reply. I have had numerous times, especially with walnut where wet sanding made a huge difference on tearout.....some woods are just difficult, and even in the same wood some pieces are more difficult than others...........wet sanding does make the abrasive cut better and the slurry helps to smooth things out.......even at lower grits.

[Brice Rogers]

Hello Roger,

I am not a finish expert.

But I have wet sanded with thinner as well thinned WOP. I think that if you were sanding with thinned WOP, that you may end up filling some of the torn pores. Perhaps that is what you want.

I also saw a demo where Kelly Dunn from Hawaii (IIRC) routinely wet sands with BLO. IIRC, the slurry helped fill the pores.

I saw a Youtube video where a person had tear out and he fixed it by applying some oil and re-doing some shear cutting or shear scraping. I've tried various oils (even BLO, WD-40 and paint thinner) and found that they each give some improvement in tear-out. BTW, Using oil on a metal part when machining is pretty common and it is often done for the roughly same purpose - - to eliminate/reduce tearing and improve surface finish.

I have also applied a drenching coat of thinned poly and have also used Minwax Hardener to assist in removing tearout of punky items. Both helped.

[Roger Chandler]

Hello Roger,

But I have wet sanded with thinner as well thinned WOP. I think that if you were sanding with thinned WOP, that you may end up filling some of the torn pores. Perhaps that is what you want.

Thanks Brice......what I really want is to remove the tearout, before finishing........hoping that wet sanding will take care of those stubborn spots.

[Brice Rogers]

Roger, I don't think that you can go wrong with wet sanding with BLO or thinner.

If your scraper has a fresh burr or if your gouge is razor sharp and you want a minor experiment, try oiling (BLO or thinner) applied to the piece and see if it helps. I find that it is beneficial. It often removes about 80 plus percent of the tearout (depends on wood type and conditon) and minimizes some of the sanding.

[Mike Nathal]

Wet sending with walnut (WO) oil works well for me. I see no reason that you can't thin WOP. My only issues with wet sanding with thinned WOP or AO is the mess it makes, plus you have to take measures to minimize skin contact with solvents. You can put WOP on top of wood that is wet sanded with either thinned WOP, thinned AO, or WO.

[Roger Chandler]

Wet sending with walnut (WO) oil works well for me. I see no reason that you can't thin WOP. My only issues with wet sanding with thinned WOP or AO is the mess it makes, plus you have to take measures to minimize skin contact with solvents. You can put WOP on top of wood that is wet sanded with either thinned WOP, thinned AO, or WO.

Thanks Mike......I wanted to go ahead and make some progress on this calabash bowl this evening, so I thinned some Mahoney's Walnut oil with mineral spirits and wet sanded and got the bowl where is about 99%.....there is just one very small area where a spot or something darker in the wood, and punkier shows a tiny bit, but I think I have it as best I can get it. I put 3 coats of Doctor's Woodshop Walnut oil on it for a finish, after sanding to 400 grit, and will sand that back a bit tomorrow with 600 grit, and put a final finish on it........still in the chuck, and I will have to blend the area where I remove the tenon and make a flat for the base.

[Mike Nathal]

Thanks Mike......I wanted to go ahead and make some progress on this calabash bowl this evening, so I thinned some Mahoney's Walnut oil with mineral spirits and wet sanded and got the bowl where is about 99%.....there is just one very small area where a spot or something darker in the wood, and punkier shows a tiny bit, but I think I have it as best I can get it. I put 3 coats of Doctor's Woodshop Walnut oil on it for a finish, after sanding to 400 grit, and will sand that back a bit tomorrow with 600 grit, and put a final finish on it........still in the chuck, and I will have to blend the area where I remove the tenon and make a flat for the base.

I also want to mention that I have been quite pleased with the surface of a walnut oil-only finish, especially on Bradford Pear. After it cures, Beall buffing (all 3 wheels) produces a silky smooth semi-gloss. My standard practice is to wet sand with full strength WO, wait for curing, and go directly to buffing. Not sure you would need that 600 grit step. Also, to play it safe, I would let the WO cure if I was going to add WOP on top. You can accelerate curing by sitting the piece in the sun for an afternoon. Or in winter I use my kitchen oven at 140 F for a couple hours. The punky area may not look as nice with this procedure. If you don't like the WO-only finish after buffing, you could then remove it with 600 grit and apply WOP at that point.

[Prashun Patel]

Roger. Wally Dickerman advised many times the virtues of wetsanding through your grits. I trust his advice over mine, but I couldn't get it to work well.

For my money and time, the only thing that works to remove tearout (other than a deft gouge) is working slowly up through the rough grits (60 or 80) and changing paper often. I have not found wetsanding to help.

If you wish to wetsand, I would actually use water if you can protect your metal parts.

If you are going to use MS, there is no harm in putting WOP over top.

If you are going to use WOP, don't bother to thin it as it is already thinned with MS. You can use pure polyurethane and thin it with MS 25-50% to make your own WOP, incidentally.

It is ok to put WOP over a wetsanded surface with an oil finish. Just make sure the surface has been dried thoroughly. It is often hard to do this if you soak a lot of oil on the surface, because it may continue to leech out over time. If you wish to use an oil finish to 'pop' the color, then wipe it on thin so it stays near the surface, and then let dry, then proceed with WOP.

Minwax tung oil FINISH is an oil/varnish blend, but applies functionally like a pure oil: wipe on, wipe off.

You'll get a bigger, glossier build with WOP (which is pure urethane VARNISH). You'll get a silkier, inthewood finish with oilvarnish or pure oil.

That's a lot of info, but what kind of look specifically are you going for (sheen, build level, color)?

[Roger Chandler]

Thanks for your input, Prashun. Due to time constraints, I went ahead yesterday and did the wet sanding with Walnut Oil. Up through the grits as you mention Wally advised you. It took care of about 99% of the problem. When turning, I put a fresh edge on the scrapers for the final passes more than I normally do...this particular piece of wood was just problematic. The techniques I used for the final turning on this has gotten me a surface on previous occasions where I could start sanding with 240 grit, but not this time. Well, there were parts of the wood where that good a surface was achieved, and parts where tear out occurred....go figure!

I guess I need to turn more......seem like the skills need honing a bit after an extended layoff of a couple of months due to health issues, vacations, work schedules, etc.