On 8/14/2014 7:00 PM, Carl Ijames wrote:
The most common (cheapest and easiest to use) material is PLA (polylactic
acid), and next is ABS. I think both of those respond well to an acetone
vapor soak, which melts the surface a tiny bit so it flows and becomes
smooth and shiny. Kind of like fire polishing glass.

I've watched videos of people doing the vapor soak to alter the surface
finish. I've yet to see one that did a good job without a loss of
detail. Knobs typically have ridges around the perimeter as a grip
surface. Such a vapor polish would likely cause the ridges to erode
away along with any markings that might be on the knob. But look at
some of the videos and decide for yourself.

Rick


"Tim Wescott" wrote in message
...

On Thu, 14 Aug 2014 13:51:01 -0500, Dave M wrote:

I'm starting to get interested in 3D printing. My primary purpose would
be to make parts for obsolete equipment, and other parts that are no
longer available. These parts often have imbedded metal parts, such as
a metal ferrule inside a knob, or an imbedded nut or mounting tab.
Can 3D printers make such parts? If so, is any additional equipment or
unique model of 3D printers required?

Monoprice has a model that appears to be a clone of a Makerbot printer
at about half the price. Reviews seem to indicate that it is an
excellent printer, although not perfect. I guess that 3D printers are
relatively new on the scene, and will improve in time.

Thanks for any insight,
Dave M

Before you contemplate investing much money in 3D printing of knobs, check
out the surface finish attainable by your intended 3D printer. The ones
I've seen all have some sort of pattern left on the part, as an
unavoidable consequence of the printing process.

You may be able to print a knob and then sand it and polish it, but I
don't think you'll be able to just print a nice shiny knob.



--

Rick