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3M Bristle Disk

Posted: Wed Aug 26, 2015 1:46 pm
by edintexas
I saw Jody using a 3M Bristle Disk on his welding cart project so naturally I knew I needed one. Same with Norm Abrams or any of the other DIY helpers. If they use it, you need it, right?
I found one on Ebay for $24 including shipping. I made it through about 42 feet of 1" square tubing before it became all but useless. I'm an engineer, so I'm not the brightest apple in the barrel but if my calculator still works that's about 57 cents a foot to clean up the mill scale. I wasn't adding any pressure, just letting the weight of the grinder do the work.

Re: 3M Bristle Disk

Posted: Wed Aug 26, 2015 3:55 pm
by TRACKRANGER
edintexas

Was it the same brand that Jody and the others used?

Maybe there are different quality items available...

Sorry to hear of your failure, but a big welcome to the forum though.

Trev

Re: 3M Bristle Disk

Posted: Wed Aug 26, 2015 4:13 pm
by ttreb4
That's about the same experience I have had with those and similar style discs. Even on flat sheet of steel they didn't last very long. I have found the best bang for the buck is Walter Enduro Flex Flap 40 grit sanding disc. They are generally about $8-$10 at my local LWS.

Re: 3M Bristle Disk

Posted: Wed Aug 26, 2015 6:10 pm
by edintexas
Same, exact one that JC was using in the video. You can actually get them in different grits. I agree that the Flex Flap is probably still the best bang for your buck.

Re: 3M Bristle Disk

Posted: Wed Aug 26, 2015 8:58 pm
by rick9345
Mill scale is one tough customer. Just ask a machinist how hard it is on tooling.

Re: 3M Bristle Disk

Posted: Wed Aug 26, 2015 10:16 pm
by weldin mike 27
Next time, only remove the bits for welding, and investigate another method for complete stripping. Many many items have been painted Right over the mill scale and are doing fine.

Re: 3M Bristle Disk

Posted: Thu Aug 27, 2015 8:43 am
by Rick_H
rick9345 wrote:Mill scale is one tough customer. Just ask a machinist how hard it is on tooling.
A lot of truth to that statement...

I also use a flap disc to clean up the areas where I'm welding, if you need to clean up the entire piece cold rolled may be a better choice if it fits your application...less clean up ;) If not I use my Metabo burnishing tool with a sanding roll 40g-80g to clean it up, then step up in grit to achieve the finish I need.

Re: 3M Bristle Disk

Posted: Thu Aug 27, 2015 9:13 am
by soutthpaw
Those disks are ceramic dust impregnated in plastic. Used them for years for removing gaskets in auto repair setting. But I would never think of using one for large mill scale removal. They give really nice uniform finish on critical surfaces, cylinder heads, blocks etc. NAPA sells them in 2 and 3 inch. Never seen them for angle grinder. Always used then on die grinder. Jody possibly got them sent free as a demo... Who knows. Flap disc, wire wheel or sandblasting

Re: 3M Bristle Disk

Posted: Thu Aug 27, 2015 11:28 am
by ldbtx
Jody did mention in the video to be careful not to hit the edges of the stock with the bristle disk because it knocks the bristles off. They do a heck of a job in the video, but I haven't gotten any because I don't think I want to have to baby a tool like that.