... Using the Cratex wheels is also a painstaking and
time-consuming process which requires some practice/skill also to
not do more harm than good.
True enough. The smaller the tool or wheel, the harder it is to
keep the surface even and flat. By the way, if you're actually using
Cratex brand wheels, you'd be pleased with your results if you try
the various types of silicone rubber wheels instead. Cratex rubber
wheels are optimized for working steels in tool and die work, and
aren't as good on our soft metals. I especially like a rather soft
and flexible gray colored wheel carried by many dealers, that's rated
as a soft coarse grit, but the finish you can get with it, due to
it's softness and flexibility, is quite good. Much nicer feel to
them than the kinda rough feeling cratex wheels.
I am still curious through what grit sandpaper does everyone
normally progress before proceeding the buffing wheel?
Depends on the work. Sometimes I stop with 220 grit, on gold when
I'm in a hurry and things are easy to lap. On platinum, I prefer to
go to around 400 or so. But the Gesswein platinum polishing
compounds are so effective that sometimes I've gone to them straight
from a fine cut file or a relatively coarse paper like that 220, or a
3 emery, which is pretty coarse... And where I work, most of use
just use that #3 emery on a majority of ordinary surfaces that don't
need higher refinements before polishing. This may be due to the
fact that we've got a full time polisher who's quite good, already,
at removing a good deal of metal in his quest for the perfect polish.
Given his sometimes heavy hand, going to a higher grit than that
isn't always needed... but if you're doing your own polish, and
working on really precise things that need to keep that precision,
you may want to go all the way to a 600 grit. You don't normally
need to go higher than that for most work, even with platinum.
I am also still curious if anyone knows what grit the red crocus
cloth is equivalent to?
I don't think it really equates. It's finer than most actual grits,
and the abrasive is rouge, so the particles are producing a
different type of mark that abrasive particles of harder materials..
But if I had to guess, I'd guess at about 1200 grit or so. Maybe
I could use a tool that provides a narrow strip (~3mm) of
sandpaper on a firm (and also narrow) "stick" where I can easily
and frequently advance the sandpaper to a fresh surface.
You can buy cool little plastic sanding sticks that are color coded
so you can keep track of which grit is on which. They've got a
spring loaded end, and use a closed loop of abrasive cloth, around a
quarter inch wide or so. which goes end for end around the stick,
being held in place by that spring tension. As the strip wears, you
just move it around the loop. One end of the stick comes to a narrow
profile, so it gets into tight spaces.
You can also buy, usually from tool and die places, abrasive tapes.
These are like sturdy round or flat cords, coated with abrasives.
And if you want really flat narrow little abrasives, you'll get
longer life from the paper or cloth if you glue it to a stick or your
choice. The 3M sanding films are very durable, and glued to narrow
plastic or metal strips make fine long lasting tools.
And one other favorite tool, long unavailable, but now again
available, are the "scotch stone" abrasives. Also labeled "water of
ayre" or something of the sort. They're like a soft slate or
something, available as sticks from an 18 inch square and up. Use
them with water. The ends are easily shaped, and you just rub it on
the metal where it quickly takes the shape of the surface you're
working on, and with water, also is quite effective at removing
metal very evenly and gently.
Allcraft carries these little gems.