There's a couple of ways to achieve this, the traditional way is a slash-loaded brush-backed sanding like the Engis head originaly manufactured by a company called Vonnegut (these days I think that English Abrassives make them but I'm not sure). The
Unicon head by Slip-Con in Denmark is a similar system but modernised. These brush-backed heads work up to a point, but really require a rotation speed of 500 to 1000 rpm and they do have a tendency to sand the widest part of a profile heavier than the narrowest and to dub-over the edges on fine detail. Some manufacrurers like
Flex-Trim use differential size rings to overcome this fundamental deficiency.
An alternative is to go to something like a
Fapi-Flex wheel which is made to your profile - however there is a lead time on these and they aren't the cheapest.
The only "intermediate" step are soft abrasive wheels which can be formed to your shape. These are available from the abrasives companies and I'd suggest talking to SIA, English Abrasives, Norton, etc. rather than most woodworking machinery dealers who know as much about this subject as they do about dust extraction - i.e. nix. This is the sort of wheel I use on our Volpato sander - and strangely we have had them from a machinery dealer,
JMJ Woodworking Machinery near Hull (ask for Steve in Tooling), although it has to be said they
are the distributors for Volpato in the UK.
One of the problems that you will have is that most spindles won't drop below 3000 rpm which is actually way too fast for most abrasive systems which are better run at 500 to 1200 rpm (too fast and you get short abrasive life, rapid glazing of the abrasive loading and burning).
If the profiles are straight there is a simpler approach: spray some glue onto a sample of moulding and closely wrap with 60 or 80 grit abrasive. Abrade a block of insulation foam (the denser extruded stuff) to form a mirror image of the profile. Spray the mirror image block with adhesive and attach abrasives. To motorise add one
Festool Duplex straight line (linear) sander.
Scrit
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