Wet sanding backing blocks

[Paul Rhoney]

Hey finishers,

What kind of backing blocks are you all using when wet orange peel? I've been using these foam blocks (probably weather stripping) for a long time now, and I think they must be too soft. I have a second theory that maybe they're just too small, and that spreading the area I'm sanding out will help. But as it is now, I'm sanding out all the shiny spots, and I'm left with too much chop. The surface is wavy and not as flat as I want it. I'm not starting with excessive orange peel, and it's a urethane finish. I'm not so much talking about the sides and contours (I make electrics), for whatever reason I seem to get sides and contours that look plenty flat enough with my foam blocks and fingers, it's just the larger flat surfaces that are too choppy.

Also, I've tried using a wooden block, but it sort of "skips." It's like there's a suction that's being created and the wooden block just sort of sticks in place and it's not easy to push around in a nice gentle circular motion.

So what kind of block are you guys using, or what material is it, and how big is it?

[Bob Gramann]

I use a gum eraser.

[John Sonksen]

pink eraser for detail stuff, for larger flat areas I use cork glued to some decent plywood. Same kind of stuff you'd use to make a tack board with and you can cut them to whatever size you like.

[Peter Wilcox]

I use these I got at the Dollar Tree. Fairly dense foam, with very little give, and about 2 1/4" diameter flat faces. Cut in half, four for a buck.

http://1.bp.blogspot.com/-K4aWdeHsIGE/U ... 0/dice.JPG

[John Catto]

Typical stationery type white pencil eraser. I use the cork type blocks as well but only for sanding the wood. Regarding the wood, where I need it to stay hard and flat I use the small aluminium sanding beams you get from model plane shops, I use double sided tape to attach the paper. I also have a very long one which is great for flattening the gluing surface on a neck.

[David King]

I take a 2" x 4" square of 1/4" lucite and cut shallow grooves across it every 1/4" on the tablesaw. I have smaller ones as well.

[Brad Heinzen]

I did a full interior demo on a house a while back, and part of what we pulled out was carpeting with a thin rubber pad. I made up some sanding blocks by laminating pieces of this rubber pad to plywood, and they turned out to be perfect for all types of sanding. They're soft enough that the paper doesn't load up when dry sanding, and firm enough for leveling all sorts of materials and finishes.

[Michael Lewis]

If you are sanding off all the shiny surface yet still have high and low areas I think your sanding block is too soft and you are using too much pressure. You want the abrasive to catch the high areas and leave the low ones. Forcing a soft pad into the surface will make it follow the contours of the surface and sand the low spots as well as the high ones. I use light pressure for sanding most of the time as it helps avoid loading the paper and it mostly catches the higher spots of the surface. Practice, practice, practice, and practice some more. Sanding is an art, pay attention to it.

[Paul Rhoney]

Thanks for the comments, fellas. Upon my return to the shop, I tried a few different things and definitely got some better results with a larger surface area (a bigger block), and a few different papers that I tried. It seems there's something in the geometry of the height to width to length ratio of a block, that can make a harder stiffer block glide easily without the sticking problem I had before.