3M Sanding Blocks

Has anyone tried the 3M rigid and flexible sanding blocks used in boat building? They use hook and loop and have a 4.5" x 30" foot print. Rolled or pre cut hook n loop paper is available in a good selection of grits. Im thinking they should work good for large areas like doors or roofs where the surface is either flat (rigid sander)or flat with a slight contoured (flexible sander). I have durablocks (but not 30") and a set of the flexible sanders (up to 18") with the removeable rods that adjust the flex. The flexible sanders offer a 36" sander but its well over $200. The 3M sanders are under $60.

3M always makes some good stuff regardless.Pricy? Yeah but since I got back in and Looked at s'paper prices.Was quite shocked as too them.
H&L will be pricy as the 'process' to involve you to use It.
I got 'jacked as to 3m 'reversing' the h&l and having a lot of stock,the 'other way'.
Sad....

Mike, yes the paper is pricey but the use of these sanders is pretty limited (my very limited experience). Just an initial blocking followed by smaller blocks. When you consider the size of the sanding sheets, 4.5 x 30, they are huge. Also, the rolls are a better deal than the precut. I dont follow your response, "I got jacked as to using 3m reversing theH&L and having a lot of stock the other way". Are you saying 3m reversed the hook and loop pattern between the board and paper?

I ordered the flexible 3M 4.5 x 30 sanding block from Amazon. Went on back order. Meanwhile I had ordered two rolls of 80 and 180 rolled paper but when the showed up they were the narrow rolls that fit smaller sanders. Something happened on Amazon and the 4.5 rolls I ordered have been removed and now the only paper available is the individual sheets that cost around $10 per sheet. Ouch! Thinking the limited use of a sanding board this big might not be a good investment at $10 per sheet.