Cleaning rust off of cast iron tops - Jack's angle grinder method fail

[Cary Falk]

I’d like to see pics of the setups you guys tried where it didn’t work. Because it’s either the setup or the technique.

No picture but here is my issue. The pressure you need to keep the pad on the wire cup presses the wire cup through the pad. The wires scratch the cast iron. If I wanted that then I would just use a wire brush. An angle grinder is just too fast. I prefer the variable speed of my Porter Cable buffer/polisher.

[Warren Lake]

more thoughts. Brian are you using Burgandy 3M? thats the only one i use, tried others didnt work well, also my makita has a speed control and I have it turned down low, likely 1 or 2 its all I need and I likely dont use much pressure for the most part, Lower RPM works better from the burgandy staying and cuts better.

[Tom M King]

You have to keep the cup pretty flat too. I've used the Burgundy, Gray, and Gold Scotchbrite pads that are sold in rolls for autobody work. They all work fine. This on an old, single speed Black & Decker 15 amp side grinder with twisted wire cup. You have to press hard enough for the pad to stay on, but not too hard for the bristles to poke through.

There is a good possibility that the twisted wires don't poke through as easily as straight wires, but this is the only setup I've ever used. I've never scraped first either. Heavy rust just eats the pads faster, but they come on a 15 foot roll for about 25 bucks.

edited to add: Looks like they are called "knoted wire" instead of twisted: https://www.mscdirect.com/browse/tnp...QaAuw5EALw_wcB

[Matt Day]

Yes, the wires start to come through as the pad wears down. Just slap another pad on.

[John A Murray]

Could probably attach a scotch bright to a 1/4 sheet square sander and have at it.

+1

I had an old 1/4 sheet sander that was no longer in use. The scotch bright pad fit (almost) perfectly. It was not quite as wide as the sander but there was no effect on the "sanding" and was much easier than doing it by hand.

[Jeff Duncan]

I use an angle grinder but not the wire cup method. I use a sandpaper disc attachment. It's basically a plastic backer and a nut washer setup so I can cut sandpaper or scotch brite pads and fasten them on securely. Don't remember where I got it but works great and you don't have to worry about anything flying off!

good luck,
JeffD

[Larry Edgerton]

For an old machine I am trying to rehab I take my Makita flat wheel tool grinder and turn it upside down with a 220 stone in it, working in a pattern until it is close, switch to the 800 stone for a pass. Trick is to resist the temptation to work harder on bad spots and stick to the pattern. Then I go to a scotchbright stuck to an old ROS pad.

[Jayson B. Williams]

I am new to Old Vintage Wood Working Machines. I have a 1935 Craftsman Bench Saw. I was told to use a Angle Grinder with a wire wheel. As you can see, this was all done by wire wheel. You can use WD40 to coat it, then grind away. I have also heard the blade method, which I have never done before, So you need to find what works best for you.

Jayson

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