My Bosch 5" ROS has recently become very hard to handle. I have had it for
a few years now and have always found it to be quite easy to handle and yet
powerful. However, lately I have barely been able to keep it on the work
surface. I can see that it moves in both the circular as well as random
motions still. I took the pad off to see what I could and found that there
is a rubber ring that rides against the back of the sanding pad to direct
the airflow for the dust collection through the proper ports. I found that
the ring was caked with paint residue. Not thinking that this was relevant,
I cleaned the residue off anyway before I put it back together. It was much
more manageable, for a while. It went back to its difficult behavior fairly
quickly. I took it apart again and found that the ring was again covered
with paint residue, (BTW I was trying to sand out some primer). I cleaned
it again and it ran better. I do not understand why the paint residue would
cause it to behave the way that it does. Has anyone had the strange
problem? I was thinking about putting a very light coat of silicone spray
on the ring to see if that would prevent the paint from sticking to it.
Does anyone have any better ideas?
Me neither but I haven't seen an ROS disassenbled to see how
they work normally.
Even the tiniest trace of silicon oil residue on wood will cause
fisheyes in subsequent finishing attempts (except with shellac),
or so Bob FLexnor says in _Understanding Wood Finishes_.
So it is probably a bad idea to use silicone lubricants on
Silicone does not go away. I work in a high energy research lab, using
epoxy and glass & graphite fibers. A test was done on silicone
persistence. One year after introduction, (one event) it was EVERYWHERE!
Got a female one eh?
> I took the pad off to see what I could and found that there
Some sanders have a wear part in them that control the orbital action. (My
DeWalt even came with a spare) Perhaps something is worn enough not to
direct the air properly, but enough that it is not at full capacity. Check
the manual for references to something like that.
If you're doing something like sanding off old finish you're probably
much better off using a belt sander than an ROS to begin with. I've
always considered the belt sander to be the work horse and the ROS to
be for much finer surface work.
On Sat, 13 Aug 2005 00:21:06 GMT, "Highland Pairos"
Like Ed mentioned, I remember reading a tool review in one of the
mags lately that talked about the brake pad wearing out. The brake
pad acts as a "buffer" to keep the pad from starting right out on the
random orbits to allow you to work your piece. If that is worn out it
will act or orbit strange. You should look at your owners manual to
see if the ring you mention is the brake pad and look to replace that.
Thanks folks. I know about the issues with silicone and that's why I didn't
just try that solution without some input. Ed and Allyn thoughts about a
wear component that effects the orbital actions makes sense. When I have it
on the piece and under load it seems like it only spins and that there is no
orbit to 'redirect' the motion. It might makes sense that a wearing or worn
part would let it orbit with no load (which it does) but is too worn to do
it under load.
Course now I have to try and find the manual.
I have a Crapsman(Ryobi) ROS that occasionally starts vibrating & becoming
"hard to handle". I discovered that the screw retaining the pad assy.
bearing to the motor shaft had loosened slightly. After 2 or 3 occurrences,
I tried some Loctite on the screw threads, it's been fine ever since. Seems
this would fall in with the comments about worn parts.
Just my $.25
The greatest headaches are those we cause ourselves.
On Sat, 13 Aug 2005 15:13:40 GMT, "Highland Pairos"
From the Bosch web-site on sanders:
Find you model and click on the link and it will give you a link to
the owner's manual and part diagram. Not sure which one you have, but
from the varibale speed manual:
"NOTE: If you notice steadily increasing no-load speed, this
indicates that the damper ring is worn and needs to be replaced."
According to the manual, the damper ring is used to reduce no-load
speed to prevent accidental marking of the workpiece...
HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.