Creating custom sanding blocks

[bradleyheathhays]

I've got a resin project coming up where I'll need to sand all of the resulting form's epoxy facets from 120-3000 grit. Because the surfaces will be between .75 sq in and 2.5 sq in I need to create very small and lightweight, but absolutely flat sanding blocks. I tried attaching sheets to 1/4" MDF chipboard using titebond but they curled considerably. So now I'm left wondering what to use. It's a shame the board didn't work because it's thickness and weight would've been perfect. Any ideas for how you could make extremely stable sanding blocks of this size?

 

[jttheclockman]

Google is your friend. Contoured sanding blocks have been used in woodworking for many many years.

https://www.walmart.com/ip/14Pcs-Co...p.ds&msclkid=af6bc5b1177a183e1251a1e6325d5083

https://www.amazon.com/contour-sanding-block/s?k=contour+sanding+block

 

[Joseph]

For thin and flat sanding block I would try 1/4" plexiglass and a spray adhesive like 3M 77 to attach the sand paper

 

[Monty]

If the spray adhesive doesn't work try contact cement.

 

[monophoto]

What kind of abrasive are you using? And how are you doing the glueup?

I've had good experience using Titebond to make sanding blocks, but there are two things that I've always done that I think helped. First, I've used fabric-backed abrasive rather than paper. I can understand that paper might want to curl, but fabric backed adhesive would be stiffer. The other thing is that I've always clamped a kaul over the face of the abrasive until the glue cured to keep it flat. A scrap of MDF with a layer of shipping tape works very well.

 

[calabrese55]

There are sooooooooo many ways to do this simply. If I understand your post it is focused on process to stick a piece of sandpaper to something very flat & stable.

Lets turn the "think out of the box syndrome" upside down.
Take a full sheet of silicon carbide sandpaper and stick it to a sheet of glass. With the silicone carbide paper (it is wet or dry paper) you can stick it to the glass with just water, yes water it will hold the paper to the glass and be absolutely flat or just go the spray adhesive route. the water stick makes it simple to change paper to finer grits.
Now instead moving the sanding block over your resin piece move the resin piece over the sandpaper

Here are a couple of links that may help

calabrese55

 

[jttheclockman]

After rereading your post I agree with #55. Adhering sandpaper to glass or as I do a piece of tile. This makes for a flat true surface. I use 77 spray adhesive. Then you sand the piece over the paper and it is a matter of you holding the piece square to the paper. Any variations is on you. Nothing more you can do unless you make some sort of a sanding jig and ways to hold the piece square. Good luck.