RO 90 First Time User Questions

Dick Mahany

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Jan 8, 2016
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Used an RO 90 or the first time yesterday with both the round and delta shape hard pads and 180 grit paper.  I'm sanding my maple workbench skirts and trestle preparing for a fresh new coat of oil.  I noticed the machine really jumps around if not held very carefully in all modes.  Adjusting the suction on my CT 36 didn't seem to make a noticeable difference.  Also, due to the position I was in, I had one hand on the underside of the rear of the tool near the dust port and it got very warm, almost hot.

My question to the experts out there is whether these are normal?  I have used a forced rotation dual action auto polisher and suspect that the jumping may be the way I was holding the RO 90 to the surface and would appreciate your experiences.
 
The part about it getting warm, almost hot is normal.  As for the jumping around, yeah it can do that in RO and rotary modes until you learn to finesse this sander (personally, I've not had much trouble with the delta mode jumping).  Try holding the sander with one hand wrapped around the front and the other at the back on the cord/hose while trying to hold the sander as flat to the work surface as possible.  When you get it right it doesn't take much to guide the sander around in a controlled manner.  By controlled I mean relatively speaking.  The RO90 isn't as easy to handle as the larger random orbit sanders.  Its the nature if the small sanding surface with a long tool body.     
 
You can also try and throttle down the vac a little. Sometimes too much suction makes it unruly. All depending on surface, sanding mode and how powerful the vac is though.

In my experience with the RO90 it worked best for me with the vac turned down a little. Both on the MIDI and the CTL26.
 
What Brice said... [big grin]

I've owned and have used mine for the last 5 years and it can still get "bouncy" depending upon grit, grain and movement direction. I think it may be less than when it was brand new, but I'm not positive about that. Can't really remember it bouncing in the delta mode either.

Like Brice mentioned, a 2-handed grip is best for control. Even when polishing smooth plastic headlight covers it can act up. A firm grip but a light touch kind of brings things back to normal.
 
Many thanks for the help and information, I found them all useful  [not worthy].  After several hours today using and adjusting my technique, I did indeed get the tool to calm down in rotary modes. As far as the jumping in the delta mode, it was the pad contacting adjacent 90 degree surfaces where I wasn't paying close enough attention.  I didn't realize the orbital path was as large as it was with the delta pad, and was just letting the edge of the pad come into contact causing the sander to jump away.

In all, this little machine is great for small areas and details, where my only other option would be my Fein Multimaster.  The ability of the RO90 to sand in three modes is unique and now I just need more practice (and unfortunately a need to purchase more sandpaper grits.)  I also appreciate the ability of the RO90 to get into sharp inside corners such as the edge features on this vise jaw.

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A coworker of mine sent me a video of the Rotex sanders hanging from a bungee cord and simply allowing them to run unloaded for about 5 hours.  He believes this technique allows the tools to break in.  I personally have not tried this technique, but my coworker is pretty smart and damn attentive to tool care and maintenance.
 
I've been using and abusing power tools since 1971.  My father was an Air Force fire truck mechanic.  He advised me that when ever I bought a new vehicle or tool to run them hard immediately.  His theory was that if they were going to fail, thrashing them out of the box would make this happen.  I've run five Ford vans into the ground at over 250,000 miles each, all following his advise with minimal life time repairs.  I had a 3/4 ton that only ever had two exhaust systems and two sets of tires...total repairs.  Whenever I buy a new corded tool I run it a full speed, no load for at least 10 minutes, forward and 10 reverse.  I then run them the same way at the lowest speed.  I must be lucky, because despite owning most tools known to modern man and quite a few that most modern men do not know exist, I've never had a new tool fail.  Oh, and most of my corded tools were taken apart and 20' cords installed before i even ran them.  My corded 37 year old Milwaukee 1/2" hammerdrill has drilled hundreds of thousands of holes and has only been repaired once.
Poor old girl hasn't been used for two years now that my 18v whipper snappers have taken over!
 
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