Replies

1. 
   jako17 | Mar 12, 2005 03:52pm | #1

   The word is Dynabrade!!!!!

1. 
   mike4244 | Mar 12, 2005 05:13pm | #3

   Make sure your compressor can handle the air consumption. Most air powered RO's require a lot of cfm's.

   mike

1. 
   LeeGrindinger | Mar 12, 2005 05:19pm | #4

   I use a Dynabrade, it's a wonderful sander but while I use it a two stage Rol Air compressor runs continiously in the background. In other words, it probably costs as much or more to run as your table saw.But, the 3/32 orbit will leave no swirl marks.LeeMontanaFest

1. 
   Jimma | Mar 12, 2005 05:44pm | #5

   Would a 60-gallon Campbell Hausfeld qualify as adequate?

1. 
   RickL | Mar 12, 2005 07:06pm | #7

   Compressoers are rated for given CFM at a certain pressure and good air tool companies give the requirements of their tools so you can check the requirements before you buy. 3 hp is goung to run a lot with an air sander while 5 hp is fine. 60 gallon tank isn't enough to verify if your compressor is suitable.

2. 
   Jimma | Mar 12, 2005 08:34pm | #10

   Well, I didn't have the rating handy when I posted the 60-gallon figure. But, I just checked and the compressor says 10.2 @ 90 psi. Looks like Lee is suggesting a bit more is required (or better) for continuous operation.

3. 
   LeeGrindinger | Mar 12, 2005 08:09pm | #8

   Probably not, Jim. Like Rick says, tools and compressors are rated by cubic feet per minute usage. I bought the Rolair just to keep up with the Dynabrade and it just barely does so. I think you'd be hard pressed to find a single stage that would keep up. Having said that it does not mean that you can't run a Dynabrade off a small compressor, it just means you won't be able to run one continiously. I replaced a "5" horsepower Coleman upright with a 60 gallon tank becaise it didn't come close. Compressor motor ratings are also a concern, if you're running a motor continiously you'll kill it, they need to rest too. 85% is about as much as a motor should run.There are some really good electric ROSs out there, I don't pay attention to tool reviews but an esteemed friend rated a bunch of them and one in particular got really good ratings, I think he liked it nearly as much as a Dynabrade. It was a review that apperead in a magazine other than FWW so perhaps someone here will chime in with the brand.LeeMontanaFest

4. 
   Jimma | Mar 12, 2005 08:39pm | #11

   As I just said to Rick, my 10.2 CFM doesn't look better than marginal. I do have some electric ROS and they've performed well for me, but I thought I might start thinking along the lines you mentioned -- maybe switch over on the next big job. Probably won't, now.By the way, I ordered a video from Ian Agrell about a month ago, followed up with an email and haven't gotten a response. Do you know if they're on vacation, busy, or what?

5. 
   LeeGrindinger | Mar 12, 2005 08:59pm | #15

   I have enormous respect for Ian but I've never met him or spoken with him in any form. I have no idea where he is or why he's not responded to your e-mail. I really need to get out more, I'd love to meet Ian as well as Nora Hall. ...maybe a road trip up the west coast some year. Maybe they'll come to MontanaFest, I'll be inviting them so who knows?LeeMontanaFest

6. 
   Tao | Mar 12, 2005 08:20pm | #9

   Dynabrade makes the best air powered ROS on the market, but the 5 inch models require still 16 to 18 CFM to run properly.  Your 60 gallon C-H would probably keep up for non-production use, but you'd have to listen to it  run a lot.  Check the CFM rating on the compressor label to be sure.

   I have a National Detroit and have owned a couple of Sioux ROS's that aren't as good as Dynabrade, but are still good sanders, use less air, and cost considerably less when I bought them.

   FWIW, Dynabrade makes electric ROS's also, but I have no experience with them.  If they are like the rest of the line, they ought to be pretty good.

   Michael R

7. 
   Jimma | Mar 12, 2005 08:41pm | #12

   Thanks for your response. I guess I said what needed to be mentioned in the above messages. Probably won't go for the electric dynabrade.

8. 
   BillLindau | Mar 12, 2005 08:55pm | #14

   I have a 7.5 hp 80 gal compressor but didn't like using the Dynabrade. My favorite is the Porter Cable Quicksand ROS with a contour pad. It is way more agressive at lower grits and does great up to 320 grit, which is where I stop and start rubbing with steel wool.  Bill

   PS I think Liberals are good people. Will this get my post moved to a secret, undisclosed location, like the one in Guantanamo Bay?

9. 
   Jimma | Mar 12, 2005 10:10pm | #17

   I'm not sure about liberals these days. I went to one of the most liberal colleges in the US and thought I knew one when I saw one -- and then I see Clinton fraternizing with Bush right out in public. Maybe they will blame it on what you can get from Clinton's cigars (which are probably Cuban).

10. 
    lwj2 | Mar 13, 2005 06:35pm | #23

    Muwahahaha. It's working. Everyone thinks Gitmo is a secret.:)Leon Jester

11. 
    DDay | Mar 12, 2005 10:51pm | #19

    The new porter cable is rated for 15 cfm @90 psi.  So you won't be able to run it continuously.  I would say other sanders will be close to this in air consumption.

    http://www.porter-cable.com/index.asp?e=547&p=5809

12. 
    kipper | Mar 12, 2005 11:13pm | #20

    I have heard wonderful things about the Dynabrade, but sadly I've never used one. I have, however, owned a Desoutter ROS (now part of Chicago Pnuematic, I believe) which was pretty darn good but didn't have dust extraction and I did spend a while working for a shop with Festo (Festool) air powered ROSs (even better, and reallly good DX).  My own puny 20cfm (FAD) compressor runs hard to keep up with an air-powered ROS (I second the comments about profligate use of air bynROSs) so I now use Festool electric ROSs in the shop. Arguably the best electric on the market. good balance, not too noisy, not to heavy (although way heavier than the Festool air ROS) and well braked, although I can only compare them with the Bosch and Metabo electrics, neither of which are as good. I'd say go for a 6in over a 5in simply because you'll cover a greater area in a given time

13. 
    LeeGrindinger | Mar 12, 2005 08:52pm | #13

    I should add a bit about compressor ratings. Compressor ratings are given as a CFM (cubic feet per minute) rating. Horsepower ratings are meaningless. Amperage ratings are a bit more meaningful if you're looking at motor ratings.CFM ratings can be one of three numbers. The CFM of displaced air, the CFM of delivered air or the CFM of compressed air. Compressor dealers and manufacturers will generally use the rating of displaced air for an obvious reason, it's the highest. Displaced CFM is the amount of ambient air the compressor sucks in. The best of compressor heads are around 75% efficient so toss 25% of displaced CFM out the window as far as buying a compressor based on the tool requirements. As psi in the tank increases efficiency in the head decreases due to leaks. A two stage head is more efficient for higher psi's and higher psi's in the tank mean larger volumes of compressed air in storage.CFM of delivered air is a much better number and it's the one that air tool manufacturers use in their ratings. This number is the CFM of uncompressed air needed at the tool. Compressor manufacturers don't like this number as much because it's smaller than the displaced air CFM and it rarely makes us drool as buyers. A rating of 15 CFM at 80psi means 15 CFM of uncompressed air when it's delivered at 80 psi. Compressors lose efficiency as the psi increases hence the lower ratings as the psi increases. The bottom line here is that if you're buying a compressor based upon the ratings of your air tools buy one rated at least 20% higher than your anticipated tool requirements.CFM of delivered compressed air is rarley used because it's generally a small number that makes buyers giggle and manufacturers blush. I have seen this rating used by some tool makers in the hopes of selling a tool to users that think they'll be able to run it off that tire inflater you keep in your car trunk. If you see a tool with an absurdly low CFM requirement the manufacturer is using this number. Don't buy the tool, you already know the scruples of the manufacturer.LeeMontanaFest

14. 
    Jimma | Mar 12, 2005 10:04pm | #16

    Egad! I didn't expect a tutorial on compressors, but I appreciate it. Guess my C-H falls into the category of bike tire inflators. However, it will also blow off the top of my work bench when I'm expecting my wife to come to the shop, and so far it's been good for impressing the neighbors as well. Yep, that rating game is chasing customers all over the place in several tool categories, especially ones having to do with electric motors. As I said earlier, my DeWalt, Bosch and other ROS will have to do for now. Thanks for the info on Ian, too.

15. 
    Jellyrug | Mar 13, 2005 10:01am | #21

    Lee,

    Compressors are normally rated at Free Air Delivery (FAD)

    In Europe there is a standard published for this, as below:

    Free air delivery. Air at the atmospheric conditions of the site and unaffected by the compressor. Flow is measured at the discharge valve of the compressor, after the aftercooler, the water separator and built in check valve. Capacity and power consumption are corrected to ISO 1217 standard reference conditions: Ambient temperature = °20C, Ambient pressure = 1 bar(a), Relative humidity = 0%, Cooling water/air = 20°C, Effective working pressure at discharge valve = 7 bar(a).

    Here in the US, most compressor ratings are normally given as above, with the exception that the FAD rating is given for a specified PSI, such as 90 Psi, or 40 Psi.

    It follows that if your compressor rating is for example given as 11 CFM, at 90 Psi, the 11 Cfm refers to standard atmospheric conditions, almost the same as FAD. At 40 Psi, you will get a little bit more, probably for the same machine around 13 CFM, as you have said, due to efficiency gain at the lower pressure.

    Also, all tools or spray guns etc., refers to FAD here in the US.

    Unless, a tool is used continuously, non-stop, which is unusual, if you have a 60 gal tank, you can normally get by with a machine which is around 10% smaller than the rating on the tool you are using.

16. 
    LeeGrindinger | Mar 13, 2005 05:20pm | #22

    I believe Europe is much more regulated about this that the USA. Compressor ratings are not as reliable here. I have had discussions with engineers that work for Rolair and much to thier credit they list both numbers as they do here... http://www.rolair.net/sc.php?page=2&value=44&subcat=3%20HP%20Two%20Stage%20Models but the lower end brands are not so generous with their numbers. LeeMontanaFest

2. 
   RickL | Mar 12, 2005 05:05pm | #2

   Dynabrade is a good brand. Look carefully the specs. They make them with a couple different size orbits. Smaller is better for fine sanding.

3. 
   KeithNewton | Mar 12, 2005 05:50pm | #6

   I have a little Souix 3" that I use for detail work that I love. This should not be your only sander for large broad areas, but for getting into tight places or edges, and contours. It has a hook and loop pad, and the two finger switch gives good speed control for those most delicate area like around where the background and carving meet.

4. 
   hairball | Mar 12, 2005 10:34pm | #18

       I have used Dynabrades extensively over the last 10 years or so. They are the industry standard and rightfully so. My personal preference is for the 5" model. I find it more maneuverable, it gets into tighter spaces and has less tendency to wander.

5. 
   pdxman1 | Mar 14, 2005 01:00am | #24

   Anyone try the Grizzly H6192? It is in their 2005 catalog, marked as new. It says it uses 5 CFM and it has a dust port.

6. 
   frenchy | Mar 14, 2005 05:42pm | #25

   I have both and a big compressor so trustme on this,  for wood working use the electric. I like Mikita's round one because it's qiuet and vibrates less than others I've used.. The air powered ones work fine on body work but not so great on wood.. in a pinch I would use them but I'd rather have the quietness of my Mikita.

1. 
   Jellyrug | Mar 14, 2005 05:52pm | #26

   The problem is when you do a bit of wet sanding, such as the early stages of rubbing out a top, finished with laqcuer. The quickest way to do this is wet sanding using mineral spirits and you don't want any electricity here due to the fire hazard.