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

  1. #1
    Join Date
    Feb 2008
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    NE Connecticut
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    695

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

    So I felt extra motivated this afternoon and decided to clean all of my tops. The summer was extremely hot and humid for my area and I had surface rust on several machines. I tried the method from the video below, which involves putting an abrasive pad under a wire cup attached to an angle grinder. I had no success with it.

    https://youtu.be/-uMrVusnaEg

    I tried this once or twice before but have never been successful. I have tried two different wire cups and a few different abrasive pads but, each time, the wire cup cuts through the pad. This happens very quickly. Has anyone here been able to do this? Any thoughts about why I can't make it work?

    Not wanting to waste my motivation, I put the abrasive pad under an old POS ROS. This worked fairly well but was much slower. It also removed the hooks from the bottom of the sander. Do not try this if you ever want to attach sandpaper again.


  2. #2
    Join Date
    Oct 2005
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    Camas, Wa
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    3,848
    I have had zero luck with that method as well. I put a scotch brite on my Porter cable right angel hook an loop buffer/polisher. It doesn't really stick to the hook and loop but it stays in place fairly well.

  3. #3
    I've also not gotten it to work. I find the pad goes flying.

    I "sacrificed" a hook+loop pad on my Rotex for this task (as you say, Brian, it wrecks the hooks). But then I bought a box of Festool Vlies pads (green scotchbrite with hook+loop compatible backing). So there is a ~$700 solution available, if you were curious

  4. #4
    Join Date
    May 2017
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    Rancho Palos Verdes, CA
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    Yep, a scotch brite pad under a cheap cordless detail sander + WD40 has been my go to after trying just about every other method seen online.

  5. #5
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    Feb 2008
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    Northwestern Connecticut
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    Could probably attach a scotch bright to a 1/4 sheet square sander and have at it. Or hot melt glue a scotch bright to a spent hook and loop pad, that I've done.
    "A good miter set up is like yoga pants: it makes everyone's butts look good." Prashun Patel

  6. #6
    Join Date
    Feb 2014
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    Lake Gaston, Henrico, NC
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    It works for me with a 15 amp side grinder, and a twisted wire cup wheel. That's what stays on that grinder, so that's what I've been using, without bothering to put a cupped wheel on a small grinder. I don't bother to cut the Scotchbrite pad into a circle though. I just use the whole rectangular pad, and don't worry about the corners spinning out past the circle. Maybe you're pushing down too hard, or not hard enough to keep the pad on, but not destroy it. It's really fast with that big grinder.

    Those of us who produce work for a living, and use tools all day, every day, do so many little things without thinking about it, that I can see why Jack wouldn't have said anything about the amount of pressure being important.

  7. #7
    Join Date
    Dec 2005
    Location
    West Lafayette, IN
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    I’ve been using Jack’s method for years with great results. It’s my go to.

    First thing to do is razor blade scrape the top. Rust causes a lot of friction and makes it harder to keep the pad on.

    To keep the pad on you need to apply constant pressure. Simple as that. Once a pad starts getting torn up, I leave it on and slap another one on. Again, constant pressure and it stays on. Sometimes it will catch an edge and it flies across the room so fast it’s a scavenger hunt to find it. But no big deal.

    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.

  8. #8
    works very well but only on Wakin Machines burgandy scotchbrite I cut them to size just barely enough think six per piece if I remember correctly four for sure. Even done it on round bit its more difficult. Ticks me off to see the last stuff I did starting to rust again. Neil was right.

  9. #9
    Join Date
    Sep 2016
    Location
    Modesto, CA, USA
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    I have a piece of seat leather that I use in a square sander with car polishing compound. I find a ROS and 400-600 grit paper is the easiest.
    Make it easy on yourself and thin the floor wax with thinner to a slushy paste. Much less rubbing needed to get full coverage down in the rust pits.
    Bil lD.

  10. #10
    Join Date
    Jul 2013
    Location
    Flower mound, Tx
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    514

  11. #11
    agree with John that it works well, even on non wadkin. its interesting to see how some machines simply do not rust the same even in the same space. nice machines and shop there John


    Capture.jpg
    Last edited by Warren Lake; 09-24-2018 at 2:13 AM.

  12. #12
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    Dec 2005
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    West Lafayette, IN
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    John that is a sweeeet sander. I’d love to have one at some point. Nice work.

  13. #13
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    Feb 2008
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    NE Connecticut
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    OK, well, I believe it can be done since several of you have said you do it and there is clearly video evidence. I've got another CI surface that needs cleaning so I'll try it again and take pictures of my setup. Maybe I'll make it work this time.

    Thanks for the responses.


  14. #14
    I forgot to mention often ill use a riazor blade first, likely Jack recommended that, some rust is sharper and stronger than my sample there and doing the razor first scraping it the burgandy will go further.

  15. #15
    Join Date
    Dec 2005
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    West Lafayette, IN
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    Definitely give it another try. Remember you need to keep the constant pressure. Apply pressure, turn on. If you let up you’ll have a scotch brite projectile to find. You’ll get the feel for it.

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