As Geoff has said the media is a very fine ground glass, it can be various grades. It won't embed itself into the casing, that's internet talk from people who have probably never had anything vapour blasted.
The big issue is ground glass left in bearings, oil galleries, fuel ways etc, that's why you have to be clinical in cleaning after vapour. When I do carbs I'll strip them as far as you can, ultrasonic clean before to get the rubbish off them, then vapour blast, flush in clean running water and air line dry, then I'll put them back in the ultrasonic until there's no residue left in the bottom of ultrasonic tank.
There is an argument that soda blasting is better for critical areas, as in those above, but it's no way as effective. It certainly wouldn't have cleaned Geoff's cases as effectively as vapour.
You also have to be very careful to completely dry the components after vapour blasting as it's easy to get flash rusting on metal parts, or discolouration on alloy parts.
You pays your money and takes your choice...

I made a soda blaster many moons ago, in fact it'll be way back on this thread... I only used it on my carbs, but I gave up on it years ago. Now when I do carbs I just strip them and ultrasonically clean them... don't vapour blast, they come up pretty good in the tank to be honest

Decided yesterday to get my finger out and get the engine rebuilt for Tenere 2, also I wasn't particularly happy with the decals that the paint bloke did... so after a chat with him when I picked up the 4MY stuff he offered to do it again for nothing.... not really nothing cos I've had to buy another set of stickers ... and strip all the bodywork off.
Anyway now he tells me it'll be ready for Xmas, BUT... he's not happy about putting the decals on, so I'll need to either do it myself or find someone who can do 'em.









Developments on Tenere 6... the guy in Wales still hadn't started my body work, so Dan (Cadno) kindly offered to pick up all my stuff and take it to his painter to do, and not only that he's asked the guy to stop working on one of his bikes to do mine... top man Dan, I can't thank you enough mate...
Having seen the quality of the stuff he's had done I can't wait to see it finished...

Back on to Tenere 2

Lovin the white frame and contrast of colours, not long now until the bodywork is eventually reunited
Keep up the good work fella....

The engine is back in





Decals applied, need to remove the bodywork again for lacquering