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03-05-2019, 06:14 PM
(This post was last modified: 03-05-2019, 11:43 PM by Tony (Charleston WV).)
Just curious. Even if the claims of the seller are reasonably accurate, I'd have a problem paying $120 for three grits of anything. There's also the issue that it's likely that I'll be moldering in the ground before I could make use of the claimed lifespan. Tangent alert: I have a real minor heart issue and when I asked my cardiologist what the likely prognosis would be, he told me not to worry--"you'll be dead before it kills you".
Thanks.
Oops. Sorry.
here
Tony
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is this a game of stump the dummy? What sandpaper?
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(03-05-2019, 06:14 PM)Tony (Charleston WV) Wrote: Just curious. Even if the claims of the seller are reasonably accurate, I'd have a problem paying $120 for three grits of anything. There's also the issue that it's likely that I'll be moldering in the ground before I could make use of the claimed lifespan. Tangent alert: I have a real minor heart issue and when I asked my cardiologist what the likely prognosis would be, he told me not to worry--"you'll be dead before it kills you".
Thanks.
Link missing....
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(03-05-2019, 06:58 PM)Admiral Wrote: Link missing....
Likely
Dura Grit, mentioned by
Stumpy Nubs.
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03-05-2019, 09:13 PM
(This post was last modified: 03-05-2019, 09:15 PM by mvflaim.)
(03-05-2019, 08:30 PM)Alan S Wrote: Likely Dura Grit, mentioned by Stumpy Nubs.
I had one of those things. Bought it 30 years ago at The Woodworking Show. Worked until the sheet metal bent. There were also round metal discs you'd put on a random orbital sander and spin it like crazy. Dangerous as hell when the disc flew off.
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"Lasts 100x longer" but an 8x10 sheet of Norton 3M ProSand is $1.50. But since a standard sheet of sandpaper is 8x10" and the Dura-Grit is only 2.5" x 5" (almost 8x as much area as the Dura-Grit block), then even if it lasts 100x longer than sandpaper, it's still 2x more expensive compared to sandpaper (take the area of the "sandpaper" and divide by the area; then multiply the cost of the standard sandpaper by 100).
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Allan Hill
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(03-06-2019, 07:24 AM)AHill Wrote: "Lasts 100x longer" but an 8x10 sheet of Norton 3M ProSand is $1.50. But since a standard sheet of sandpaper is 8x10" and the Dura-Grit is only 2.5" x 5" (almost 8x as much area as the Dura-Grit block), then even if it lasts 100x longer than sandpaper, it's still 2x more expensive compared to sandpaper (take the area of the "sandpaper" and divide by the area; then multiply the cost of the standard sandpaper by 100).
I'm grateful that someone did the math.
I was wondering how this worked out.
Thanks
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03-06-2019, 09:22 AM
(This post was last modified: 03-06-2019, 09:22 AM by Rob Young.)
(03-06-2019, 07:24 AM)AHill Wrote: "Lasts 100x longer" but an 8x10 sheet of Norton 3M ProSand is $1.50. But since a standard sheet of sandpaper is 8x10" and the Dura-Grit is only 2.5" x 5" (almost 8x as much area as the Dura-Grit block), then even if it lasts 100x longer than sandpaper, it's still 2x more expensive compared to sandpaper (take the area of the "sandpaper" and divide by the area; then multiply the cost of the standard sandpaper by 100).
Agreed.
I get 3x the cost using $1.31 per sheet for the 3M "pro" grade paper just based on square inches.
$1.31/(9*11) = $0.013/square inch for paper
$38.23/(5.5*2) = $3.48/square inch for block
But, heck toss in the cost of a couple cans of spray adhesive so you can make a square edge block once in a while (considering the wood as $0.00) then it still comes out between 2x and 3x.
It gets only slightly better if one uses the cost of pre-glued rolls of sand paper instead.
3M stikit gold 2.75" x 75ft runs about $60.
$60/(2.75x75x12) = $0.024/in^2 which still comes out ahead on the 100x cost claim.
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(03-06-2019, 09:22 AM)Rob Young Wrote: Agreed.
I get 3x the cost using $1.31 per sheet for the 3M "pro" grade paper just based on square inches.
My bad. I used 8x10 instead of 9x11. Thanks for catching my error.
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