Sanding these pesky spots

[j24j]

I have to sand a lot of inside radius sections in my project and am looking for the wisdom of the group on how to sand these areas. I've got about 75' of this to get done. Elbow grease is an option, but I'm looking for the experience and wisdom of the group on how to handle this since I need to do this as quickly as I can due to the schedule for my work space.

Thanks for your advice in advance!

[bljones]

I like these:

Contour Sanding Grips - Lee Valley Tools

Or go to your local home building store and buy backer rod- it is used to fill cracks prior to caulking. It makes great sanding grips.

TAGO | Backer Rod Foam Insulator | Home Depot Canada

You will probably only need to sand by hand in a few spots- much of the radii pictured will be sanded when you sand the nearby flats with your orbital. As a cheat, if you have a 4.5" sander, use 5" discs- the edges will curl up and allow you to sand into the curve.

[merc2dogs]

Backer rod and the grips would work fine.

Typically I use styrofoam blocks cut to shape and then wrapped with sand paper. It's stiff enough to sand well, but soft enough to conform without digging in.

The oversize sheets on a sander work well, but use the sander a bit on flats so the paper beings curling before you try it in the corners, a fresh sheet is stiff enough that it will often cut into the curve, leaving little gouges.

[Kimana]

Playdoh! I was playing w/my 3yr old granddaughter this afternoon and I was kneeding this big thing of playdoh!lol Just came to me that you could wrap a piece of sandpaper around a large chunk if this stuff (contained in a ziploc bag) and jamb it into your contour and sand away.