Good 80-grit sheets for Disc?

Erin Burke

Erin Burke

KnifeMaker...ish
Joined
May 19, 2003
Messages
1,330
Hey guys. Do any of you have recommendations for a good low-grit sheet for use on a 9-inch disc?

I have been using Rhynowet Redline paper and love it for grits >=120... but I bought a batch of 80-grit for post-HT truing of flats, and the grit just flies off of it. No longevity at all. I'm really looking for something around 80-grit that cuts for more than a couple passes on a heat-treated blade.

Erin
 
Other than buying expensive psa discs, I've had good luck with buying "Old Stock" Cloth Backed Sheets off ebay. It's a bit hit or miss, since its mostly all AO but different coatings and such can affect performance, but I have more of a problem with glazing than loosing grit with most of the X weight cloth sheets in sub 120 grits.

You can usually find 50 sheet reams for $20 or so shipped. Look for the brands you're familliar with, like 3m. The 120grit three-m-ite elektro cut sheets I got are great, the 50 grit 316RB sheets glaze easily. The problem is, 3m made a zillion different configs, and the realistic information available for the different types is non existant. Still, they're all tougher than any non cloth sheets, and grit loss isn't the main concern with them.

Hope that helps!
 
DO you think the rhynowet problem is due to the speed of the disc sander, or the paper? I was just about to order a huge box of paper from them, so I can start hand sanding stuff. Granted im not using 80 grit, just 120 and up.. so it might not apply anyway.
 
mgysgthath said:
DO you think the rhynowet problem is due to the speed of the disc sander, or the paper? I was just about to order a huge box of paper from them, so I can start hand sanding stuff. Granted im not using 80 grit, just 120 and up.. so it might not apply anyway.
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I don't know brother... I'd be happy if if was just a bad batch, since I've been so pleased with their higher grit papers. But I can actually feel the big grit flying off the paper... not good.
Erin
 
Don't hesitate to order Rhynowet, especially if your only getting it to hand sand with. I used to use expensive Mirka paper until Nick convinced me to try the Indasa stuff. Its definitely better and cheaper. Power sanding and hand sanding are totally different concerns anyway, but the Rhynowet redline is great for both.

The issue I think with power sanding using papet with really course grits is really just the size of the grit in relation to the available bonding power of the substrate. I don't use sub 120 grit paper (only cloth backed) simply because none I've ever tried has held up, it either strips grit, or rips the paper. The cloth is tougher, and porous enough to hold the abrasive and adhesive better.

There's a reason most abrasives, sheets or belt or whatever, targeted at the metal industry, are constructed on a cloth backer. For the finer grit stuff, it's not really a concern, but we're the exception in the industry, in that we usually take finishes up to much finer grits using our particular equipment. I'm not saying other metal workers don't polish, but they're usually not doing it the way we do.
 
I think you make good sense javand.. and certainly for my application if it's good enough for Nick Wheeler it's good enough for my meager talents, lol.
 
Gotta echo Javan on this one too.

A 9" disc with coarse grit has a lot working against it... a very small surface area, rotating/abrading against a comparatively large surface area.

I've never tried Rhynowet coarser than 120X.

But I do have some other coarse 9" discs that I use on occasion.

You can get blue Zirconia discs from Tru-Grit "relatively" cheap for how well they work and how long they last. I have a couple 50X than can easily grind the bevels on a blade (with sufficient hp, of course). But I RARELY use them.

The second option, may not be an option anymore... The local Lowes used to sell Gator Grit 9" black zirconium discs. Those things cut like crazy, and were cheap. Unfortunately, they quit selling them, and I haven't been able to find a Gator retailer than can get them. I don't use them very often either, but if you need to get aggressive with some steel on the 9" disc, they are definitely up to the task.

Since you don't live in the sticks like I do Erin, you may have better luck finding them. (your thread reminded me to try emailing Gator Grit again to see if they can point me toward a retailer that does sell the discs :) ).

Here's the link to Tru-Grit... bottom of the page. They also have Blaze discs, but I've never used them and can't see paying the price.

http://www.trugrit.com/disc-psa.htm
 
javand said:
The issue I think with power sanding using papet with really course grits is really just the size of the grit in relation to the available bonding power of the substrate. I don't use sub 120 grit paper (only cloth backed) simply because none I've ever tried has held up, it either strips grit, or rips the paper. The cloth is tougher, and porous enough to hold the abrasive and adhesive better.
Click to expand...

This makes sense Javand... thanks.
 
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