Malcy,
There is nothing wrong with modern abrasives, they do their job well for what they are designed for, and the latest developments like Abronet (designed for the aircraft manufacturing industry) are even better. I've not tried the new ceramic or diamond ones (I'm not that rich).
The problem is not the abrasive, it's how we use it, we put it against timber that is rotating too fast, cause the facets of the grit to break, blunting them, overheating the paper (or cloth) causing it to breakdown the adhesive that holds the grit on, or the loop backing.
That's the problem, Us, abrasives don't like heat and high speed.
Don't say it, we should sand/abrade at under 500 RPM, I know that, but how many of us do it religiously?
And lets do some sums, were sanding a 12" platter with a 2" disc, the lathe is rotating at 500 RPM;
So for each rotation of the platter the disc (at the extreme edge) is rotating up to 6 times, multiply by the lathe speed, that's 3000 RPM. Are you really sanding at 500 RPM?
Result, grit breaks down, glue breaks down, disk flies off, okay not always and normally we don't sand as low as 500 RPM but at 1000 RPM the abrasive disk is doing 6000 RPM etc..
George,
Yes Rhynogrip is great stuff, it sticks to the hooks on the inertia sander very well, it's got a good abrasive coating, but J weight abrasive is still the lowest grade of cloth backed abrasive available. There are better ones.