Best Die Grinder Attachements for Rust Removal?

[BikeRider]

I just bought a Milwaukee M12 Fuel right angle die grinder along with a bunch of batteries ranging from 2Ah to 6Ah, and intend to use it to remove surface and relatively minor pitted rust and caked-on crud from underbody car parts like a subframe, sway bar, rear diff, brackets, etc, along with small patches of surface rust on body panels that are otherwise structurally sound. The car's in pretty good shape, just needs years of mostly surface rust removed.

I'd also like to clean the inside surfaces of some old wheels, both steel and alloy. And, eventually, I hope to derust various engine bay parts like manifolds, heat shields, block exterior, etc., but that's still a ways off.

I'm just confused by the different kinds of attachments that are available and wondering which would work best for this sort of application and am wondering which ones work best for this sort of job:

• Abrasive Discs
• Bristle Discs
• Sanding Discs
• Grinding Discs
• Grinding Bits
• Flap Wheels
• Wire Cups
• Wire Wheels
• Carbide/Diamond Burrs

Did I miss anything? I know about Roloc so I'm mostly interested in what kinds discs/cups/wheels to use and not how to attach them. I don't have a compressor so no air tools like a needle scaler, which would be overkill for my needs anyway, and I'm overbudget so I doubt I'd be willing to invest in other tools like sanders, polishers, oscillating tools, etc.

In the past I mostly used drill/driver attachments of the above types, a rotary tool for hard to reach spots, some chemicals (mainly phosphoric acid gels and Evaporust), and hand brushes and scrapers. It worked, but was slow and painstaking (literally as my hands got numb and tingly for weeks afterwards which I later found out was due to using a drill and driver), which is why I got the die grinder, to make faster work of it and hopefully avoid the hand issues.

 

[Jagmandave]

I use my angle grinder with a twisted wire wheel on it, works a treat and the "battery" never goes dead and needs to be changed!

 

[BikeRider]

I use my angle grinder with a twisted wire wheel on it, works a treat and the "battery" never goes dead and needs to be changed!

Unfortunately this die grinder only works with 1" & 2" wire wheels which might be tough to fit in some spots. Anything bigger will likely stall it. I did order a 1" braided DeWalt wire cup for tight spots, but my rudimentary research indicates that with die grinders your best bet for rust removal is abrasive "surface conditioning" roloc discs for larger surfaces. But I'm wondering what the real-world experience is for folks here.

 

[GeoBruin]

The roloc abrasive/surface conditioning discs you're describing are phenomenal at removing rust. They are, in my opinion, actually more effective than a wire wheel on an angle grinder. That said, they wear down pretty quickly, so I tend to use the angle grinder with the wire wheel to knock the big stuff off on a first pass and handle all the large surfaces that are easy to access. I then switch to the RA die grinder in tighter spaces or if I really need to expose bare metal.

I also order thos little discs by the box. I've snagged several amazon warehouse deals linked from this forum and I keep an eye out for specials from Empire Abrasives or Benchmark Abrasives.

Hot tip... get a roloc adapter for 3inch and 2 inch discs but only buy 3 inch discs. When the 3 inch discs wear down to the point where your little rubber arbor is making contact with the work piece, unscrew the disc and throw it in a drawer for later. Next time you have some fine work or need to grt into a tight space, swap over to the 2" arbor and use the worn down 3" discs.

Cheers!

 

[BikeRider]

The roloc abrasive/surface conditioning discs you're describing are phenomenal at removing rust. They are, in my opinion, actually more effective than a wire wheel on an angle grinder. That said, they wear down pretty quickly, so I tend to use the angle grinder with the wire wheel to knock the big stuff off on a first pass and handle all the large surfaces that are easy to access. I then switch to the RA die grinder in tighter spaces or if I really need to expose bare metal.

I also order thos little discs by the box. I've snagged several amazon warehouse deals linked from this forum and I keep an eye out for specials from Empire Abrasives or Benchmark Abrasives.

Hot tip... get a roloc adapter for 3inch and 2 inch discs but only buy 3 inch discs. When the 3 inch discs wear down to the point where your little rubber arbor is making contact with the work piece, unscrew the disc and throw it in a drawer for later. Next time you have some fine work or need to grt into a tight space, swap over to the 2" arbor and use the worn down 3" discs.

Cheers!

Thanks. I have that $10 HF corded angle grinder along with their $10 starter wheel kit, but I have to work on my car on the street so getting power to it will be a real pain. Of course parts that I remove from the car (and I intend to basically remove the entire rear end to do a thorough job including the underbody) I can bring closer and use the angle grinder with. But I live in a 2-story apartment building and the neighbors and landlord are going to have a problem with that, in terms of noise, dust, safety issues, etc., which is why I decided to get the cordless die grinder. Might require a bit more work but from a practical point of view it makes a lot more sense. No one can hassle me working on the street.

Anyway, putting aside the angle grinder (literally and figuratively), from what I've read and your feedback it looks like those abrasive discs should handle the majority of the rust removal. Do you know which grade works best, e.g. course, medium, fine? And are sanding discs not really for rust removal, whether flat or flap? What about those bristle wheels and cups that many people rave about? Also not really for rust removal? And, are HF's abrasive discs any good?

 

[GeoBruin]

Wire wheels and cup wheels are awesome, and sometimes the best way to get to hard-to-reach places, but in my experience there aren't a lot of them readily available for die grinders. While your m12 can adjust the rpm, many (most?) air die grinders aren't adjustable and spin super fast (20,000 + rpm). At that speed, most wire wheels become little weapons that launch wire projectiles.

I've got several brushes with 1/4" hex shanks that I run in my impact driver through I'm sure you could run them in and drill if you ran it fast enough. But nowhere near me sells 1/4" smooth shank wire brushes for die grinders.

The Harbor freight abrasive discs work fine but they seem to wear out faster. Worth picking up a multi-pack and trying the different grits to see what you like and then keep an eye out for a box.

Sanding disks are not ideal for most of my uses. The discs need to have some give (squish?) otherwise the part contacting the work piece is very small. The abrasive discs are kind of like a scotch bright pad impregnated with SiO2. They just work.

 

[BikeRider]

I ordered a DeWalt 1" braided wire cup that I believe is rated for die grinder use, but my existing brushes and cups I believe are only rated up to ~4500rpm, which in theory I can use with the M12 at its lowest setting, which maxes at 10k rpm, but very gingerly and only wearing full PPE.

But I probably won't bother. Those I got for use with drills and drivers which are much slower. So I think I'll take your advice and just focus on abrasive wheels. I used those with the driver and drill and they worked out pretty well. But I'm new to die grinders so I guess I'll just have to experiment and see what works for me.

I also used grinding bits on occasion, for really tough rust spots that nothing else seemed to remove, but I had to be careful to not remove too much metal. Brushes and abrasive wheels did most of the work.

 

[BikeRider]

So I got a few of each of the more common kinds of discs available and will try them all out to see what works best for my needs, e.g. strip discs (purple & black), surface conditioning discs (green, yellow, red/brown), flat flap discs in various grits, sanding discs in various grits and materials, 1" braided wire cup, 2" stranded wire wheel, a few grinding bits (1/4" hex so I'm not sure they'll fit). I'm sure that between these I'll find most of my rust removal needs well-served.

But I figured that I might as well get a bristle disc or two as well, just to get an idea of how they work and see if they're suitable for my needs, likely 2" ones. Apparently 3M is the only version to get, as the others do work just not as well and don't last as long. But, do I get the green or the yellow?

This is for rust removal, mostly on underbody parts like the frame, subframe, control arms, manifolds, engine block (only OUTER surfaces with all ports sealed), etc., and maybe for some light body panel surface rust. I'm probably going way overboard but it's good to have a hands-on sense of what the various options out there can do.

 

[dnschmidt]

To answer your immediate question the green are the most aggressive bristle discs and what you should use for rust removal followed by the Yellow and then the White. The white are what you use to remove gasket material from aluminum surfaces as they don't gouge the aluminum. Question answered, but, these are not the best tools for rust removal. The strip and clean Scotchbrite discs work well but are expensive. These are the wheels with the extremely open weave pattern primarily used to remove paint. Normal Scotchbrite surface conditioning discs will load up pretty quickly and are primarily used to remove grinding marks after removing a weld with a flap disc or hard wheel.

In my opinion 36 grit abrasive discs are what you need. You get what you pay for. The best Roloc abrasive discs are 3M Cubitron II which cost a bundle but last three times as long as the cheap ****. The best non-Cubitron discs are the Ceramic discs made by either Starcke (Abrasive Resource) or VSM sold by Lehigh Valley Abrasives. Not quite Cubitron II but half the price as last 3/4 as long so the best value.

Lehigh Valley: https://www.lehighvalleyabrasives.c...hange-sanding-discs-ceramic-with-grinding-aid

Abrasive Resource: https://www.abrasiveresource.com/Ceramic-Quick-Change-Discs-s/1845.htm

 

[BikeRider]

To answer your immediate question the green are the most aggressive bristle discs and what you should use for rust removal followed by the Yellow and then the White. The white are what you use to remove gasket material from aluminum surfaces as they don't gouge the aluminum. Question answered, but, these are not the best tools for rust removal. The strip and clean Scotchbrite discs work well but are expensive. These are the wheels with the extremely open weave pattern primarily used to remove paint. Normal Scotchbrite surface conditioning discs will load up pretty quickly and are primarily used to remove grinding marks after removing a weld with a flap disc or hard wheel.

In my opinion 36 grit abrasive discs are what you need. You get what you pay for. The best Roloc abrasive discs are 3M Cubitron II which cost a bundle but last three times as long as the cheap ****. The best non-Cubitron discs are the Ceramic discs made by either Starcke (Abrasive Resource) or VSM sold by Lehigh Valley Abrasives. Not quite Cubitron II but half the price as last 3/4 as long so the best value.

Lehigh Valley: https://www.lehighvalleyabrasives.c...hange-sanding-discs-ceramic-with-grinding-aid

Abrasive Resource: https://www.abrasiveresource.com/Ceramic-Quick-Change-Discs-s/1845.htm

Thanks. I got knockoff versions on Amazon in a set that came with various kinds of discs. I'll see how well they work. Thankfully I don't have a ton of rust to remove at this point, the worst having been removed over the past couple of years using drill and driver attachments. But enough that it's worth finding the most suitable discs.

These are the ones I got:

https://www.amazon.com/gp/product/B096DBXL5T/?tag=atomicindus08-20

Also these flap discs:

SI FANG 20Pcs 2 inch Quick Change Zirconia Flap Disc Sanding Discs Mix Set Include 40 60 80 120 Grit with 1Pc Roloc Disc Pad Holder for Rotary Tools Grinder, Roll Lock Disc Die Grinder Attachments: Amazon.com: Tools & Home Improvement

SI FANG 20Pcs 2 inch Quick Change Zirconia Flap Disc Sanding Discs Mix Set Include 40 60 80 120 Grit with 1Pc Roloc Disc Pad Holder for Rotary Tools Grinder, Roll Lock Disc Die Grinder Attachments: Amazon.com: Tools & Home Improvement

www.amazon.com

I'll probably also get a single green 3M bristle disc just to see how well it works for my current and maybe future needs. For $10 it's worth taking a chance on and it might work well for complex surfaces or deep channels.

3M 07524 Scotch-brite Roloc 50 Grit Bristle Disc Green for sale online | eBay

Find many great new & used options and get the best deals for 3M 07524 Scotch-brite Roloc 50 Grit Bristle Disc Green at the best online prices at eBay! Free shipping for many products!

www.ebay.com

 

[ebj]

I've had the M12 fuel die grinder like yours for over a year. I use the Roloc 2" maroon disks for most rust removal. They strip rust to bare metal easily, but have trouble reaching inside angles and corners. A wire cup brush works in those places. Anything more than a 2" tool stalls out my grinder.

 

[BikeRider]

I've had the M12 fuel die grinder like yours for over a year. I use the Roloc 2" maroon disks for most rust removal. They strip rust to bare metal easily, but have trouble reaching inside angles and corners. A wire cup brush works in those places. Anything more than a 2" tool stalls out my grinder.

At this point I've got a few of pretty much all the different kinds of abrasive discs, cups and wheels that work with my die grinder for rust removal, except the "slap disc" kind of flap disc, where you apply the side and not the top of the disc to remove material. I might get those too, to be thorough, but mostly I just want to experiment and see what works best for me. I also have a rotary tool with various bits for those hard to reach spots that even die grinders can't reach. The most effective bits I've found for those are those tiny wire wheels and cups. They only last a minute or two and throw tiny pieces of wire everywhere, but they're very effective for tight spots and bolt holes.