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?

 

[Lefley]

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?

I use 3m spray 77 adhesive to make all my sanding blocks. I use melamine blocks left over from cutting cabinets.

 

[worn thumbs]

It will be a miserable task however you go bout it.I have rubbed down quite a few small surfaces that needed to be flat and even made sanding blocks of a size to suit.I used thicker material than you tried and used spray contact glue to attach the paper.which meant a lot of blocks,so I began with the largest surfaces and used a well worn bandsaw to cut the blocks down as I progressed through the different sized faces.It meant a block for each grit,which was really tedious,so I used scraping for as much as possible and a carefully wielded chisel can be quite helpful,until you slip and damage a face.It gets worse if you need to use wet and dry as the block can distort with moisture.

 

[Chief Sawdust Maker]

We produce signs made from wood. wood & epoxy and various plastics, all of which require some sanding to various grits, the signs range from the size of a postage stamp up to A5 size. So I spend far too much of my life sanding!!!!!
Our preferred method is 18mm or 25mm Moisture resistant MDF, I use MR in case I want to go down the wet route on the epoxy, we normally have offcuts but there are a few companies on line that will supply you with cut to size pieces.
The side that I hold i put a 6mm radius on with the router, yes some might say using a specific wood and spending time actually making the blocks is a waste of time but when you spend hours sanding I feel its worth it.
Secure the abrasive with 3M contact mount spray, spray the block press firmly onto the abrasive then trim round with a knife the block will often take 3 or 4 changes without the need to respray.
Consider weather you want to move the abrasive or the item that will obviously depend on the shape and size of the item, some items we produce we mount a whole sheet of abrasive on a large piece of MDF.
If you are holding the abrasive and its a small abrasive block then consider mounting a large block on the back of it to make it easier to hold.
I sometimes wear nitrile disposable gloves which help you grip the part and or block.
You have probably got your own favourite abrasive, from experience you get what you pay for and I tend stick with a couple of brands.
Not saying mine is the ultimate way or the best way but it works for me and what we produce,

HAGD

D