I just had a talk a few minutes ago with a technician in abrasive from SIA, and I probably learned more things about abrasives than by reading on the net for a year. A few things, while not fully related with the subject (but I think you guys will find this interesting) the tech mentionned:
- Ceramic belts are priced with how much % they have of ceramic (more ceramic = higher price). With the stats I was given, it was clear that the nortons, vsm and klingspor were not cheaper after all if you take into account the % of ceramic they got vs their price. Only the 3M were comparable in price to the SIA for the amount of ceramic.
- Depending on the situations, zirconia belts will outperform both in cut and durability a ceramic belt on simple carbon steel (mostly depends on the way the steel approches the belt). In fact, ceramic belts are not suited for mild steel, or even annealed high carbon steel.
- Unlike popular believe, ceramic belts don't need a high pressure to work properly. In fact, too much pressure will clogg the belt, make the piece hotter and make your belt not last long. The tech told me: the abrasive is here to help you grind the steel, if you have to put all your body on the piece it means the grit or the belt you have is not suited for this steel, switch to a different belt or go to a more aggressive belt.
- Using anti clogg (the tech suggested using simple a bar of soap) will significantly help avoid clogging and facilitate the grain to break
- Silicon carbide sandpaper will cost you more and have a shorter life but will give the best finish
- AO sandpaper will cost less and have a longer life but it might take longer to achieve the same finish
- With heat, AO "fuses" with the chromium oxyde in stainless steel (a chemical reaction), making it useless for this application (now think about what I said before about the amount of ceramic in a belt)
- A 70 duro rubber wheel is to soft to get the most out of a ceramic belt, 80 duro and up would be ideal. It is better to use the flat platten if you have a softer contact wheel to ease the breaking of the ceramic grain.
Now, theses infos are not from me, they are from someone whose only job is to recommend industries wich abrasive is best suited for the job, the tech even told me to try the other brands and see by myself, she seemed really confident that her product outperform Norton and VSM, she told me only 3M was a challenge. Now you do what you want with this information, I just tought this information could be useful. But in the end, the tech told me the same as you
Sam Dean
, I have to try for myself, I am the one in front of the grinder so by trying I will know what suits the best for me. Base on this information, I will go with the 36 grit. I will also keep you updated on the Norton vs SIA vs Merit (have some left), turns out I ordered some Norton R999B in 36 grit, I will compare it to the 2511 from SIA (they apparently have an even more concentrated ceramic belt, the 2515, but the tech told me it might be too much for my application)