Random orbit sanders throwing discs off

[Andy Luckman (AJL Electronics)]

Is it me?

I have a Bosch PEX400 which is a couple of years old. Disc attachment is by loop and pile (Velcro type). In use, the thing works well for a few minutes and then throws its disc off. It will then not re-attach reliably, suggesting that the loop pile is no more. A new disc restores it to health for another couple of minutes. Altering the rotation speed appears to have no effect on when the disc becomes an UFO. Holes are carefully lined up each time with the base. Deliberately obstructing the holes make no difference though.

I consider this to be a fault as it happens regardless of disc brand, including Bosch, so I bought a new sander last week. It was a B&Q own brand Mac Allister, bought as a cheapy because my Bosch is in France. Spec is dual base 150 and 125mm, variable speed random orbit.

This one shows exactly the same symptoms. Disc nowhere near worn and becomes useless.

So is it me, or is this to be expected?

[aaron.aardvark]

I have a black and decker multi sander (can't remember the exact model off hand) with the same type of "velcro" attachment. I had the same problem a couple of years back when it was brand new. The supplied round discs vibrated loose and became UFOs within minutes. I got some more from B&Q (don't remember the brand) and they behaved the same. I couldn't believe I was doing anything wrong. B&Q grudgingly refunded the discs. Since the sander works fine with the angled base for detailing I held onto it & I used it loads for that.

[Andy Dingley]

Are the disks any good? If their pile is too short, or too compressed, they won't grip on anything.

[Dave Plowman (News)]

Have you tried washing the pad on the machine? Dust etc can stop the loop and hoop working properly. My similar Bosch is several years old and still ok.

[Paul]

Also don't run the sander when the disc is not in contact with the work, and watch when sanding the edges of your job.

I nearly lost an eye once when a disc went AWOL on my bosch sander, still got the scars to prove it. LOL

[Matty F]

I was able to buy a new (non-Bosch) Velcro pad for my Bosch that made it work again. It was surprisingly cheap.

[David in Normandy]

I had the same problem after a couple of years use and put it down to wearing out the backing/velcro bit the disks attach to. Ordered a new backing/velcro disk and the problem was fixed.

[The Medway Handyman]

I've got the B&Q own brand RAS and its been a great toll, never had a disc come off.

What I have noticed with my Bosch PMF 180 multi tool, when used in sanding mode, is that sometimes part of the velco stuff from the sanding sheet stays on the holder & then the sheets fall off. It seems like the grip of the velcro is stronger that the adhesion between the velcro & the abrasive sheet. Clean up with a stiff brush sorted it.

I think it was a combination of cheap discs & them being stored in slightly damp conditions.