Sanding 2.5D MDF/Wood Carvings

[joprinz]

Hello everyone,

I have recently built a 3 axis CNC router and am doing some 2.5D carvings on MDF and wood. Somehow I'm finding it hard to hand sand every nook n corner of some carvings. Its proving to be very time consuming and my end finish varies depending on how 'tired' my fingers are I was wondering if there is a machanised way to get the sanding done. Since the carvings are in 2.5D i cant use normal disc or belt sanders. I came across Brush Sanding devices and also Flap Wheel sanding devices but I am new to those type of sanders. what is the most commonly used method for sanding carvings? Please share your experiences using various sanding devices and techniques and how effective they are...

Thanks,

Joe

[Phife]

I find it best to first optimize your toolpaths to leave as little sanding as possible, smaller stepovers for ballnose bits help alot. Also use high quality bits help as well.

As for sanding, I like to use hand sanding with sand paper, you can fold it and roll it to whatever shape you like, wrapping the pointy end of a pencil with some sand papers is a good trick.

I also like to use scrapers and metal sculpting tools used in wax and clay carving. I sharpen them up with a grinding wheel and scrape away.

I havent had much experience with flap wheels, It could work in large areas, but would probably do more harm than good in detailed carvings.

[joprinz]

Thanks Phife, I do use the techniques you mentioned. But they are sometimes VERY time consuming. Lets say I have to make 25 NOS of the same carving. I would end up sanding it more than the hours it took to carve it... I was jus wondering if there is a mechanized way to do this faster....

Joe

[dlcw]

I sometimes use a star sander chucked up in my drill press. This can be used on hard woods and very little carving detail is removed. If used on soft woods, too much detail can be removed if not careful.

[JulianDR]

I'm interested in the subject too. See this type of star sander: Molding Star Sander

Would it be possible to find or modify one so that the sanding surface faces down, and at an angle? If you could attach that kind of tool as a bit in your CNC router and run a program derived from the original program that carved the part... could it work?

Julian

[dlcw]

I think it would be a matter of having a low RPM drive motor attached to a pivoting arm that could tilt to different angles to achieve the results you want.

[dave22]

I would have to agree with Phife, treat the probable problems not the symptoms. Toolpath and tooling. Also machine rigidity and spindle runout. As my Dad always said "work smarter not harder!" So in that spirit, check out Sanding Mop about 3/4 of the way down this link Sanding supplies: drums, sleeves, discs, chucks, arbors etc.

Hope this helps and good luck.