Sanding foam cores - RC Groups
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Feb 05, 2013, 09:26 AM
Registered User

Sanding foam cores

Yesterday i discovered a great way of sanding off the "orange peel skin" or whiskers that form while cutting with a hot wire. Before I have sanded cores with worn out sandpaper, but I've always managed to damage the cores. Even if I was extra careful some foam dust still balled up and made a crease in the foam.
So yesterday I found a pack of sanding wool (scuff pads) lying on a shelf and decided to give it a try. This stuff is great. It's almost impossible to damage the cores. You still have to be careful at the leading edge, but you can sand any way you want in other areas. Because the material is like a mesh the foam dust stays in the mesh and won't ball up.
Here's the stuff I use tried -->

I hope I'm not the first person who discovered this, but I haven't heard about people using scuff pads to sand their cores.
Last edited by martig; Feb 07, 2013 at 01:35 AM.
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Feb 06, 2013, 08:02 PM
Registered User
you can also try the sponge sanding blocks, something like this:
because they are not fully rigid they tend to be easier to control whilst still retaining a flatish surface which helps with sanding accuracy. + they are thick so you have a good grip/control
Feb 07, 2013, 01:45 AM
Registered User
I think the main benefit of scuff pads is that you don't have to be so careful when sanding. If you're using reasonable pressure on the pad it's almost impossible to create creases in the foam. Also, scuff pads only take off a very thin layer of foam. You can't use them for reshaping the airfoil or anything like that.
When I used regular sanding blocks or sandpaper I always managed to create some creases in the foam. Then I had to use spackle to fill the creases and sand again.
Feb 07, 2013, 08:35 AM
Father of Fr3aK, DLG Pilot
tom43004's Avatar
I have used grey (800 grit) scotchbrite pads for a couple years to clean the ridges off of CNC milled cores. Works great.

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