Small diameter ROS sanders?

[Jamie Buxton]

I'm looking at small-diameter random orbit sanders, which I would use to sand concave furniture parts -- like scooped-out chair seats, and sculpted back rails. I think my sanding problem is the same as a turner sanding the inside of a bowl, hence the post here. I don't have a big compressor, so I'm only considering electric sanders. I see three 3" random orbit sanders. Festool and Mirka have sanders in the $500 range. Metabo has one for a bit less than $150. Am I missing any other possibilities? Does anybody have experience with these small sanders?

[John Sincerbeaux]

I have a 3” Mirka Ceros ROS. It performs exactly like the 5” or 6” which I believe are the best sanders. Of course they no longer make the Ceros sanders.
I use my 3” for leveling lacquer finishes prior to buffing with an air powered buffer.

[Joe Hendershott]

I use my Festool RTS 400 with a couple of soft pads for round things when I need to and it works well. Perhaps someone with one of the linear Festool sanders made for that purpose like the 130 would be better.

[Dick Mahany]

I reluctantly purchased a Festool RO90 due to cost for the same uses described by above. It has turned out to be an excellent although somewhat limited use tool. The 90mm sanding disks are unique to Festool although one can also get sand paper for more reasonable cost from Klingspor.

The tool has three modes of sanding and the forced orbital is surprisingly powerful and capable of sculpting. The random orbit mode performs well however the tool is not balanced and definitely requires two hands to operate. The third mode, delta action, has been useful for sanding into corners such as on recessed panel doors and is a nice feature however I wouldn't use that as a big purchase factor as a dedicated delta sander would be substantially better for those applications. Dust collection is excellent.

Although the RO90 has been a very useful tool and is very well built and powerful, if one mainly needs random orbit motion only, this wouldn't be my first choice as it would be much nicer to have a balanced one-hand sander, especially if used for long periods from a fatigue perspective.

For sanding turnings, I typically use 2" or 3" sanding pads in a close quarter Milwaukee drill but that's far from random orbit.

One nice feature of the Festool is that there are several different backing pads available that offer different hardness which are useful on curves.

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[Prashun Patel]

IMHO, for sanding seats and curved crests, you can use a 5" sander. Many sanders (like my Ceros, and I'm sure the Deros) have aftermarket soft or medium pads available. You can also get foam "soft interface pads" that attach to your existing ROS. I buy mine from 2Sand.com.

If you really want a smaller ROS, you can use a right angle drill (I use a $40 Neiko from Amzn on my bowls), and get mandrels (2" or 3") that will accomodate H&L discs (2Sand sells these as well). The issue with the drill is that it's not random orbit, so you have to be careful with swirls. However, the mandrels come in different edge profiles which can be useful for maintaining the line where the scoop starts on a chair. In fact, for the edges of the scoop, the non-random sanding can be easier to control so you can keep a crisp line.

However, IMHO, the 5" are better on furniture because it blends out highs and lows from the shaping stage. I would also consider purpose-built or gooseneck scrapers for the rear part of the chair scoop.

[Mike Goetzke]

I know you said you don't want to consider pneumatic but I bought a PROS Mini at Woodturnerswonders. It uses 1", 2" and 3" pads. It requires 3CFM @ 90psi so not a really big compressor. So for the price of some of the electric sanders referenced here you could buy a compressor and this sander for the same price or less. (I happen to have a California Air Tools 10020C. Very quiet! 5.3 CFM @ 90 psi. It's about $350 and the sander about $100)

BTW - have found the ROS is great for higher grits but rotary sander better for rough sanding.

[Mike Nathal]

Arbortech sells a contour grinder that fits on an angle grinder. It seems to work well. So does my Metabo. The Arbortech is the only one at 2 inch diameter

[Reed Gray]

I would thing the standard electric angle drill would do fine. A variety of pads to use to fit just about any shape.

robo hippy

[Richard Coers]

Metabo SXE400 2 Amp 3-1/8-Inch Random Orbit Sander

[Grant Wilkinson]

I have this sander from Arbortech

https://www.arbortechtools.com/ce/online-store/core-products-ce/contour-sander/

and the Metabo 3" ros. Both do what they are supposed to do.

[Alex Zeller]

I bought one of those cheap detail sanders from Harbor freight that comes with the triangle sanding pad. It's hook and loop. My plan is to take one of the spare sanding pads and turn it from a triangle to a circle so I can use 2" round sandpaper discs on it. I don't know how well it will work but it was cheap.

[Jamie Buxton]

Thank you all for your many suggestions. They give me much more to sort out -- which is good!

[Kyle Iwamoto]

Does it HAVE to be ROS? As others have already said, maybe just a drill and the small 2 or 3" pads will suffice. I been using mine for years. Well, not the same pad, but the system for years.
Now the triangle sanding pad detail sander does bring yet another possibility.....

[Richard Coers]

I don't know anyone sanding furniture parts with a disc sander. How do you get rid of the circular scratches you get when you use a disc sander on your parts?

[Jeff Body]

Try searching "3 inch random orbital polisher" on amazon

I wonder if you can use these with a sanding disc.
https://smile.amazon.com/ZOTA-Polisher-Portable-Polishing-Microfiber/dp/B07T9RTRNY/ref=sr_1_4?crid=1IALSVO0HO0U0&keywords=3+inch+random+orbital+polisher&qid=1572489968&sprefix=3+inch+random%2Caps%2C164&sr=8-4

[Kyle Iwamoto]

I don't know anyone sanding furniture parts with a disc sander. How do you get rid of the circular scratches you get when you use a disc sander on your parts?

Use finer and finer grit sandpaper? Use a good brand of paper helps with grit consistency. Aren't we talking about small curved areas. A regular ROS will get al the other areas.

[Reed Gray]

With flat work, the surface I start with is generally a bit smoother than what my bowls are. Most of the time I can take a card scraper to the wood, then use a ROS with finer grits, in the 220 or so range. If I was to sand out a sculpted chair seat, hopefully I would be able to start in the 120 grit range, but that would depend on how good or bad of a job I did with the sculpting. Chisels? Router? In some cases, it may just take the card scraper. The circular scratch patterns are no more difficult to remove than the straight ones. Mostly sand till you get ALL of the previous grit scratches out before moving on to the next grit. Good light. Good glasses. You can vary the scratch lines to kind of go with the grain depending on which part of the pad you are using. When you get past 220 grit, you are pretty much polishing rather than sanding.

robo hippy

[Richard Dooling]

I know you specified an electric sander but Woodturners Wonders has a pneumatic unit with modest air requirements.

Specifications:



5/16 x 24 thread female mounting hole

3 CFM's of air at 90 PSI

3mm Orbit

1/4 inch air input (works with our Snubber Hose (https://woodturnerswonders.com/products/snubber-hose-new-product))

Weight: Just under 1 lbs.

Compatible with 1", 2", and 3" sanding pad holders (https://woodturnerswonders.com/collections/sanding-pad-holders)

Ken has two ROSs listed on the site.

[Jamie Buxton]

Here is a chair I made which shows why my 6" ROS is too big.
The back is first bawnsawn, then shaped with a 4" right-angle grinder with a structured-carbide disc and then with 4" sanding discs. Eventually I want to finish sand, but when I put the 6" ROS on the concave areas, it barely touches at the edges of the sanding pad. A 5" sander would be better, I think a 3" sander would get in there even better.
On the seat, I rough shaped it with the 4" grinder with the Arbortech 3-tooth disc, and then used the same progression of sandpaper on the grinder. To finish sand I again used the 6" ROS, but it rests on the seat edge while I'm trying to get down in the scoop. Again a 5" would better, but I think a 3" sander is really what I should be using.

418624

[Prashun Patel]

If you already have a 6, then it makes sense to get a 3". The 'lip' of the scoop is really hard to define crisply. Have you tried scrapers there?

[Jamie Buxton]

If you already have a 6, then it makes sense to get a 3". The 'lip' of the scoop is really hard to define crisply. Have you tried scrapers there?

Some traditional chair designs want a crisp edge for the scoop -- Windsors for instance. But for this modern chair, I don't see the need for a crisp edge; there isn't another sharp edge anyplace else on the chair.

[Mike Goetzke]

I know you specified an electric sander but Woodturners Wonders has a pneumatic unit with modest air requirements.

Specifications:



5/16 x 24 thread female mounting hole

3 CFM's of air at 90 PSI

3mm Orbit

1/4 inch air input (works with our Snubber Hose (https://woodturnerswonders.com/products/snubber-hose-new-product))

Weight: Just under 1 lbs.

Compatible with 1", 2", and 3" sanding pad holders (https://woodturnerswonders.com/collections/sanding-pad-holders)

Ken has two ROSs listed on the site.



read my post above

[Prashun Patel]

I take your point. What I mean is that even on chairs where I don't have a sharp or crisp edge at the scoop, it's hard - after the carving wheel - for me to flatten the divots right near the edge of the scoop. So, the edge can look uneven near the edges. I am not deft enough to use a sander to get all the marks out there, and find a scraper to be handy.

BTW, Very nice (as usual) chair.

[John K Jordan]

I use ROS 1", 2" and 3" on woodturnings such as platters.

As for the drill recommendation, no comparison. The ROS gives me far better surface with no detectable scratches. After turning and hand scraping, I usually start with 320 paper and sand to 400 or 600.

Jamie, I see you are not considering a pneumatic sander. Too bad, since there are some good ones at reasonable prices. What I like best about the air-operated sanders is the size and weight is smaller since there is no electric motor. My favorite one says it uses 8 cf/m but I prefer running these sanders at a slow, gentle speed so the air use is a lot less than wide open.

418702

Sorry, I've never used an electric one with small disks.

JKJ

[Ron Diamond]

I have a 3" variable speed pneumatic random orbital from WoodTurnersWonders that I have been very happy with. I have only used it in finer grits, 220 and above. It seems well made, ergonomics are good, cost around $125 (I think mine was a bit less some years ago when I got it)

[John K Jordan]

I have a 3" variable speed pneumatic random orbital from WoodTurnersWonders that I have been very happy with. I have only used it in finer grits, 220 and above. It seems well made, ergonomics are good, cost around $125 (I think mine was a bit less some years ago when I got it)

One nice think about the Woodturner's Wonders sander, at least the one I have, is the pressure air limiting valve - I set it to run slowly and use only a small amount of air with a full trigger pull. The think is very light weighh and works incredibly well. Always it use it off the lathe with fine grits, after hand scraping

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Of course, it's pneumatic which Jamie wasn't interested in. I and students get so much use from this that if I didn't have a suitable air compressor I'd consider getting one just for te sanders.

JKJ

[Stan Smith]

Interesting thread. I have a metabo but I hardly ever use it. I have a Fein (corded) and Makita (battery_) multi tools they oscillate, but are not random orbit to my limited knowledge. I also have a Milwaukee off-set drill (corded). I used to get the Micro Max catalog, but never looked for small sanders since I do have a Dremel. I do have a proxxon mini belt sander that I use on small stuff. Don't make my mistakes though. Sometimes I buy specialty stuff and then discover that it's not what a really needed after all.