Originally Posted by
charlest
Balls are either sanded to make them dull and hook early or polished to make them skid longer before they hook.
Sandpaper, the original abrasive used on bowling balls, is graded with a grit level indicating the roughness of the sandpaper. So if a ball is sanded with a sandpaper that has a grit level of 500 grit, the ball is said to have a grit level of 500. Balls are normally sanded from 320 grit to 4000 grit. All other abrasives, including Scotch-Brite pads, Abralon Pad, Siaair pads and Abranet pads, alll have grit levels associated with them, from 320 to 4000 grit. The higher the number the finer or smoother the grit level is. So higher number will allow a ball to skid further than lower (or rougher) grit levels.
Normally balls are sanded with pads that have progressively finer and finer grit levels. So one might start with a 500 grit pad, then go to a 1000 grit pad then to a 2000 grit pad. Some might take it finer to 4000 grit.
More recently, some balls are sanded with a very rough initial pad, say 500 grit, then sanded with a very fine 4000 grit pad. As opposed to a more normall 500/1000/2000/4000 sequence which is finer than the 500/4000 sequence, the 500/4000 sequence will not go as long, but will have a harder turn at the breakpoint. Some manufacturers,instead of sanding 360/500/1000/2000will do this sequence: 360/2000. The 360/2000 vs. the 360/500/1000/2000 will have a similar relationship that 500/4000 has to 500/1000/2000/4000.
All abrasive pads wear with use. That means as you use a pad, the grit that does the sanding or abrasion gets smaller and finer, so that the pad becomes a finer grit level. So a 1000 grit pad becomes 1500 grit, becomes 2000 grit , becomes maybe as much as 4000 grit with use over time. The more you use it and hard your press when using it, the more quickly it changes grit. There's no way to measure (of which I am aware) what grit it has become.
An example of this is the 4000 grit pad which is fairly sensitive being the smoothest and finest. It takes abour 3 - 5 use before a 4000 grit pad becomes 5000 or 5500 grit. O can easily tell this when using such a used pad because the balls shines up and does not have that dull or matte look/appearance. That's when you know to throw that pad away and redo the ball with a new 4000 grit pad. Other grit levels are harder to determine. Only experience and a watchful eye will help you see what it happening.
When a ball is polished, it will have a certain grit level before the polish is applied. (Polish is basically a micro-abrasive that makes the ball shine because it takes the ball to as super fine grit level, usually above the 5000 grit range. Most balls are polished using a spinner. Sanding can also be done with a spinner. In any case, most balls which have a base grit level of 1500 or 2000 grit, when polished is applied, becomes very shiny and are usually in that 5000+ grit range. If you start with a lower grit, 500 or 1000 and apply polish with a spinner, LIGHTLY and with a small amount of polish you can get a ball in the 3000 - 4000 grit range.
You can also apply polish by hand over almost any base grit level and get an intermediate result, between 2000 grit and 5000 grit. Only experience with eye and using the ball will tell you if its gotten to where you need/want to be.
One of the crossover points between sanding and polishing is the 4000 grit dull or matte finish vs. the 1500/2000 grit + spinner applied polish. AT these stages, the same ball, drilled the same, thrown by the same person, on the same oil pattern, will handle the same amount of oil, with the 4000 grit dulll ball hooking slightly earlier, having slightly less backend, and slightly more overall hook and handle slightly more carrydown. The polished ball will go slightly longer, have a slightly sharper backend, hook slightly less overall, and be slightly more susceptible to carrydown.
Ball Surfaces Re: Grit on a ball
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