Best way to sand bowl interiors?

[Randall J Cox]

I have at least 10 walnut bowls to finish turning (7"-10" in dia) and sanding (with more coming). I turned them all green from black walnut chunks a friend gave me from a tree he just had cut down. They are now rough turned and I'm drying them all in our microwave. Putting each one in about 40 times at 45 sec per time with lots of cool down time in between. So when they are all "dry" I will put them back on the lathe and true them up. (You have to know I have never done this before.) Got all my info from "turnawoodbowl" utube episodes. So assuming I can put them back on the lathe and make them round again, what is the way you experienced turners sand the insides? I'm chicken, don't like sticking my hand inside a turning bowl on the lathe as my old delta lathe only goes down to about 340 RPM. As I am not proficient with gouges, I am using carbide scrapers for all my work that is leaving a rather rough surface. Thanks. Randy

[Robert Hayward]

A bowl should be open enough to hand sand the inside without worry of having your hand caught and twisted off. I hand sand mine with the lathe running. Can you post a picture of one or two or your bowls?

[mike calabrese]

I have at least 10 walnut bowls to finish turning (7"-10" in dia) and sanding (with more coming). I turned them all green from black walnut chunks a friend gave me from a tree he just had cut down. They are now rough turned and I'm drying them all in our microwave. Putting each one in about 40 times at 45 sec per time with lots of cool down time in between. So when they are all "dry" I will put them back on the lathe and true them up. (You have to know I have never done this before.) Got all my info from "turnawoodbowl" utube episodes. So assuming I can put them back on the lathe and make them round again, what is the way you experienced turners sand the insides? I'm chicken, don't like sticking my hand inside a turning bowl on the lathe as my old delta lathe only goes down to about 340 RPM. As I am not proficient with gouges, I am using carbide scrapers for all my work that is leaving a rather rough surface. Thanks. Randy

Randy
have a look here there are all kinds of tools like this
Bowl Sander, Sanding Tool for Woodworking


general listing from Amazon
https://www.amazon.com/s?k=bowl+sand...f=nb_sb_noss_2


and some specifics that may help

https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

https://www.amazon.com/Sanding-Mandr...%2C155&sr=1-28

https://www.amazon.com/BOWL-SANDER-P...%2C155&sr=1-43

calabrese55

[James Baldwin]

I have one of the sanding mandrels and it works pretty good. I also picked up a Milwaukee close quarters drill off Evil Bay that I use a mandrel in. I run my lathe at about 600 RPM in reverse. It doesn't work for
small diameter bowls anything under about 6" but works pretty good for the bigger ones. Jim
milwaukee..jpg

[Barry McFadden]

I use a mandril (3" or 2") and cordless drill as well. I usually turn Kiln dried bowl blanks but sometimes use wood from the bush that is wet. If I rough turn a wet piece I weigh it and put it in the microwave at 40% for 4 minutes and let it cool. I repeat this around 4 or 5 times until I see it's not loosing any more weight and I know it is ready to finish turning.

[Bernie Kopfer]

While I’m ok with hand sanding but I am using power sanding more and more for speed and comfort. I recommend the KJ R system 2” for smaller stuff and 3” for larger bowls. Craft Supply has them both with videos. Vince’s woodturning also. And also get the interface foam pads, they greatly aid sanding curved corners. As for the spinning off complaint, you have to learn not to do that. If you can n afford it I would recommend the Abranet discs.

[Richard Coers]

The best advice is to run the lathe slowly and let the abrasive do the work. If you can't feel some resistance for the abrasive cutting, all you are doing is making heat. Second best advice, use the sandpaper like you stole it. Using dull sandpaper just adds to the misery of sanding. Use quality abrasives and make sure all the scratches from the previous grit are removed before you move on to finer grit. All the products and videos you need for your question. https://vinceswoodnwonders.com/

[Kevin Jenness]

I use mainly power sanders, a Sioux close quarter drill for roughing and a Festool or Grex random orbit sander for finishing up, with the Roloc interchangeable pads and mandrel. The rotating non-powered devices work ok. Hand sanding produces obvious concentric scratches while the random orbits are the least objectionable. I usually stop at 320# with a random orbit where I would have to go to 600 for an equivalent finish with hand-held abrasive.

Carbide scrapers are an easy way to get started but it is well worth learning to use sharp traditional tools. It will allow you to cut down sanding time considerably.

[Reed Gray]

I tried hand sanding for a little while, looked at the inertial sanders and said nope, and went for the angle drills, the corded ones. Power sanding is just more efficient. A 3 inch disc has more than twice the surface area than a 2 inch disc does, so if I can fit the 3 inch disc in, I do. Sand with your lathe and drill at slow speeds. It is a traction thing. If the lathe and/or the drill are running too fast, the abrasives just don't get the chance to dig in and cut. I once turn my bowls, so they are all warped. My lathe will go down to 10 to 15 rpm, which is just slow enough that I can keep the abrasives on the wood, all the way around. I sand with a firm interface pad up to about 180 to 220. Favorite one is from VinceswoodNwonders, and it has a 1/4 round profile on the outer edge which is a big asset on the inside of a bowl. At 220, I switch to a medium interface pad. If I do go over 400, then I switch to a soft interface pad. The firm discs are for leveling and removing tear out. the medium grits are for removing scratches. The very fine grits are for polishing out scratches. I also made an articulated arm for sanding my bowls. It lets me rest my arm on it so all the drill hand has to do is push the trigger. This does leave the other arm free. With the coarser grits, I can spin the bowl by hand to get rid of the rough spots. A huge benefit for sanding bowls. I do have a You Tube video of it. As for the cordless drills, I don't use them. I would have to change out the batteries too often, and I sand out a lot of bowls. A goose neck card scraper, if you know how to sharpen it properly can be a big help.

robo hippy

[Randall J Cox]

Wow, lots of good information. Will start investigating all leads. Thanks to all. Randy

[James Baldwin]

The Milwaukee and Sioux close quarter drills are identical. I suspect that the Sioux was made by Milwaukee because the first one I got at an Estate sale for $15. Used it for one bowl and had a problem with it. When i opened it up the gears were stripped. I would have been able to get new gears and repair it but the gears were $140 which was about the price of a new one. The gears also fit the Sioux. I just hate to throw a tool away but sometimes one has to. When the one I'm using now dies I'll go back to Evil Bay again unless I find another one at an Estate Sale. Jim

[Reed Gray]

Actually, Sioux made the drills for Milwaukee for some years before Milwaukee made their own version which has a rubber covering for the trigger. All of these drills tend to wear out because we are using them for grinders rather than drills. First to go are usually the bearings, which can be replaced without too much trouble. Brushes go as well. I have trashed a couple of the drill housings too. I did find out that running at slow speeds does make them last longer, and don't push too hard. Just the weight of the drill is plenty of pressure. My repair bills used to be about half of what a new drill was. Haven't had one rebuilt in quite a while. I do have a couple of old DeWalt cordless drills and my tool repair guy told me to hang on to them. The new ones with all the fancy electronics in them, when they break, it is cheaper to buy a new one than to repair the old one. The market has been flooded with cheap varieties, from $30 or so and up. I did try one once, and after a month, the trigger was shot. I think they have improved a bit. Never did get in the habit of blowing the dust out. That didn't seem to make any difference in longevity.

robo hippy

[roger wiegand]

First and foremost get a really good honed edge on a bowl gouge and take a very light cut to get rid of as much tearout and chatter as you possibly can, then follow with a fresh burr on a curved negative rake scraper to take even lighter cuts and get rid of even more imperfections. Getting good at that will get rid of 90+% of your sanding problem, and is _way_ more fun than sanding. It takes forever and a day to sand through tearout.

Power sanding is the quickest way to get a bowl sanded. Start with the bowl oriented with the grain running up and down. There will be a zone between 4 and 6 o'clock what will be worse than the rest of the surface (similarly when you rotate the bowl 190 degrees). Sand that with the lathe turned off to start, otherwise you will introduce unevenness as you alternate grain directions. Then turn the lathe on and power sand with the disk running counter to the direction that the lathe is presenting the wood to you-- if the wood is coming up on the far side of the bowl use the drill direction and edge of the disk that runs opposite to that motion. Don't change grits until all the imperfections from the current grit are gone and the scratch marks are uniform.

If you hand sand be sure to get the tool rest out of the way!

[Melvin Feng]

I also have the milwaukee angle drill, and really like when I can use it with the roloc 3 inch mandrels. I bought mine from woodturnerswonders. I am still working through the sandpaper that I bought through them as well, but I've also bought some 3M cubitron 2 solid discs (no holes, but with velcro backing). They are more expensive, but not terribly so. I started using the cubitron on my 5" random orbit, and liked it enough to try out when I've gone through my current stock of 3 inch sandpaper. I have enough of the roloc pads to keep one per grit, which is what I would also recommend. It wears out the velcro faster to need to keep swapping the sandpaper sheets, so they will last much longer to keep one per grit.

I do also have 2 inch pads and 1 inch mandrels when needed, as well as strips for when I have to sand by hand. I also have an inertial sander that I used for quite a while, but I do prefer powered sanding now.

[Kevin Jenness]

I strongly agree w/Melvin on the Roloc system and Cubitron.