Random orbital sander (long)

[David Walser]

There are two air powered random orbital sanders that I am aware of that might be useful for use on turnings: the Grex AOS368 - 2" 105° Angle Random Orbital Sander and the Chicago Pneumatic 7200S Mini Random Orbital Sander. I'm currently using an electric drill for power sanding. A random orbital sander would make sanding scratches less noticeable. Besides, it would be a new tool! The question is whether my 1.5 hp - 8 gallon air compressor can power either one of these effectively?

Having found the manufacture's website for both sanders, it appears the Grex uses 2.2 cfm at 90 psi -- something a small shop air compressor should be able to supply. (It would be noisy, unless you could put the compressor in a cabinet to deaden the sound.) The Chicago Pneumatic uses a lot more air: 21 cfm "under load" and an average of 10.5 cfm (no mention of psi -- if you have to ask...?). It would seem the Chicago Pneumatic requires more air than a typical small shop compressor would deliver.

Here's links to the two websites:

http://tinyurl.com/yrppl5 (http://tinyurl.com/yrppl5) (Chicago Pneumatic)
http://tinyurl.com/2fq3ag (http://tinyurl.com/2fq3ag) (Grex)

Here's links to the sanders on Amazon (so you'll have an idea of the cost, they're available elsewhere):

http://tinyurl.com/2ljj74http://tinyurl.com/3ydlw2

Anyone have personal experience or thoughts they'd care to share?

[John Hart]

Well...my personal opinion is that the Grex oughta do ya just fine. It's highly recommended 'round these parts. Mark Singer recommends it and I consider his opinion above reproach. 10.5 cfm is an awful lot of air flow requirement for a small tank to supply. When I was using a 10 gallon tank on a 2 HP compressor, I was fairly comfortable supplying 4.4 cfm and getting the job done. Since then, I have a much larger tank and compressor, but I vividly remember trying to conserve airflow. Good luck!!:)

[Brian McInturff]

I have the Grex and power it with a small PC pancake compressor. I've not had any problems what so ever. I put the compressor in a small little shed right outside and ran the hose in and can hardly here it. With the radio on the only noise I here is the Grex itself. And I know it's a quality tool compared to the Central P. AKA Harbor Freight. Go with the Grex man.
Brian:D

[Jim Becker]

The Grex will be the replacement for my Souix angle drill when it eventually dies...

[Paul Downes]

Here are some other makes to throw in the mix. I have a dotco. I think Cooper makes this one. Also there are dynabrade, master power, summit. These are all industrial strength sanders. The range in price from around $150-220. I just picked up the dotco at a salvage place for $30. Brand new in a box. It retails for around $190. And I forgot, Souix is another make.

[Hilel Salomon]

Hi,

This morning I went by my local tool supply Mann Tools(fantastic place) and asked them what good pneumatic sanders they carried. One of the owners talked up dynabrade and said that it would run 8 hours a day 7 days a week. It was reasonably priced but when he asked me what size compressor I had and I told him that I had a 30 gallon jobbie, he said it wouldn't be enough. It would take at a very minimum a 50 gallon compressor and preferably 100 gallon compressor to run it. Just thought I'd share that with you folks.

[Bill Wyko]

I used to use a small compressor and I would run it down pretty quick. Even my 30 gallon says on it not to use it for continuos use on tools such as sanders. Check to duty cycle of the compressor to see how long you can run it continuously.

[Jason Hallowell]

Ingersoll Rand also makes a nice one. They run about $120-$130, and come with a nice case and a 71 piece set of discs. Sears currently has them on sale for $112. I have used the higher end Dynabrade in automotive shops before, and they were awesome, but they also cost $500-$700, and draw a lot of air. I also agree with other posters that continious draw items like these are a great way to burn up smaller compressors. The only smaller electric one I know of is the Metabo SXE400, which runs about $125, but looks a little more clumsy than its pnuematic counterparts.

[Brian McInturff]

Well with the Grex I've not had any problems. Of course I'm not sanding really for all that long at a time. Plus I control the speed of the rpm on it also. If I think I will be sanding continuous duty then I'll break out the Milwaukee which is made by Sioux since it is electric. I just don't like the weight of it. I use to own a Dynabrade and never realized it took that much and I was running it off of a 30 gallon tank. I've got a 60 gallon tank that I need to get hooked up one day. Just have to run yet another 220 line. Remember the angle on the Grex is 105, not sure anyone else has it and it really comes in handy. Brian

[Mark Pruitt]

I have the Grex; my compressor is a Campbell Hausfeld portable 26 gallon tank, I forget the exact HP and CFM rating, but it's within the specified range for the Grex. In reality, the compressor motor runs constantly whenever I'm sanding. When the tank is fully charged, I can only run the sander for around 10 seconds before the motor kicks back on. It's a tough compressor, but I wonder if I'm going to run it into its grave. If I do I'll get a bigger one; if not I ain't gonna worry about it.

As for the Grex ROS itself, I love it! I like to use the "wave" backing pad and discs, especially on interiors. I was using an electric drill and having problems with sanding marks; so far the Grex has eliminated that problem.

[Vince Welch]

Hi David,

A ROS is very nice to have and can offer a soft finish to your project. However, they are better used at higher grit ranges starting with a grit such as 280 or 320 grit as a starting point. ROS offer a finese type of sanding action. I recommend using your power sander for lower grits such as 80 or 120 till you get to your 280 or 320 grit at which you would switch to your ROS. I offer a nice ROS unit at my site that I have used for years now. But before I sell someone a ROS unit I make sure I had this conversation with them so I know they fully understand the differences and what ROS will provide. Having the both units avaliable will provide you with the best of both sanding worlds.

The minimum tank that I would recommend is a 60 gallon tank! These tanks also use 220 volts. ROS units require more outgoing air force then most pnuematic tools. Can you use a smaller 25-30 gallon tank?....Yes you can. But here is the issue. With the smaller tanks these tanks are not designed to be running/recharging more then 10-15 minutes per hour. If they are they will dramctically reduce the life of the compressor. This is per campbell hausfeld as I called them directly and had this conversation. Now, if you want to use your current small tank unit until it dies then upgrade that is something else.

So understand you need a large tank and ROS because of their oscilating action will not remove tool marks and rough sanding mark like a power sanding set up. It is best to use a combination of both sanding tools. I hope this helps.

Vince

[Gordon Seto]

Vince,

Since you already use the regular power sanding on the coarse grits, can you go through just the fine grits briefly with ROS? Will a smaller compressor still handle that?

Thanks.

Gordon

[mike fuson]

Here in the cabinet shop it takes the 80 gallon 6hp to run a dynabrade. But if your going to just be sanding a bowl for a couple of miniutes I would think a smaller compressor would be fine.

[Vince Welch]

Hi Gordon,

IMO one's project should only require a brief sanding per grit once getting to 280-320 grit because the the surface area is becoming less coarse as one progesses higher through the grits. Minimium PSA is 90 for ROS units! There is one unit out there that claims to be less and I do not beleive it. I would have to see the unit in action to beleive the claim. Most small 26-30 gallon tanks hold 135 PSI and begin recharging at around 90 PSI. It does not takes long for the compressor to drop to 90 and start recharging!
A smaller unit (25-30 Gallon) will work. You will be able to operate the ROS using a smaller tank. The point with all my chatter is oilless unit such as the smaller tanks are not designed for ROS units as we turners will use them. SHort term they will suffice but they will not last. They are not designed to recharge more than 10 minutes per hour. So if you need to use one while you are saving up to purchase a larger tank great! If you are using one thinking I can get away with this forever. The smaller tank will probobly die when you need it most! This is an area of sanding/finishing that I have not seen covered alot but is an area that can save you time and money if you if you have this information on the front side. Hope this helps.

Vince

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[David Walser]

I really appreciate this forum. Everyone is so willing to help.

[Mark Pruitt]

Hi David,

A ROS is very nice to have and can offer a soft finish to your project. However, they are better used at higher grit ranges starting with a grit such as 280 or 320 grit as a starting point. ROS offer a finese type of sanding action. I recommend using your power sander for lower grits such as 80 or 120 till you get to your 280 or 320 grit at which you would switch to your ROS.
I know Vince has been at this a lot longer than I have, but I have to disagree here. The most significant problem I've encountered with sanding on the lathe has been marks left by coarser grits that did not show up until I was well into finer grits, forcing me to drop back and spend yet more time on an already tedious process. I have made this problem disappear completely by using a Grex ROS all the way, from 80 grit to 600. Only when I need more aggressive sanding does a drill now come into play.



The minimum tank that I would recommend is a 60 gallon tank! These tanks also use 220 volts. ROS units require more outgoing air force then most pnuematic tools. Can you use a smaller 25-30 gallon tank?....Yes you can. But here is the issue. With the smaller tanks these tanks are not designed to be running/recharging more then 10-15 minutes per hour. If they are they will dramctically reduce the life of the compressor. This is per campbell hausfeld as I called them directly and had this conversation. Now, if you want to use your current small tank unit until it dies then upgrade that is something else.


With this I agree completely. My smaller compressor does work overtime, but it's all I have and my options are limited. It's been going strong for 15 years though, and shows no signs of age. I should point out that it is a twin-cylinder compressor, not one of those direct drive oil-less cheapies. ( I had one of them too; it bit the dust in less than two years.)

[Paul Downes]

I use a right angle die grinder with sanding attachments on the lathe on occaision. I like the grinder for sanding out tearout on some woods that have that problem, such as boxelder. You can also use scotch brite type pads with a roloc attachment. another trick is to use a sanding disk that is bigger than the pad underneath and scallop the edges of the pad to allow it to flex on the curvature of the bowl.
Klingspor's makes these sanding discs if you mant to buy them.