(Topic ID: 98210)

Restoring steel with dull gray splotches

By ForceFlow

9 years ago


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  • 36 posts
  • 10 Pinsiders participating
  • Latest reply 9 years ago by ForceFlow
  • Topic is favorited by 6 Pinsiders

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    #1 9 years ago

    What is the best way to restore large steel (but not stainless) parts?

    I've tried sanding from 220 and 320 grit, then wet sanding with 600, 1200, and 2000 grit. However, after doing that, I still see fine lines on the metal from sanding. Is that something I simply have to live with, or is there something else you typically do after that before adding polish?

    Also, what do you do with parts that are shaped in such a way that makes them difficult to sand, such as the inside of the tilt housing as seen here:

    http://www.pbresource.com/images/tilt.jpg

    #2 9 years ago

    The tilt housing looks like it will fit in and ultrasonic and then the tumbler.
    OR
    A small buffing wheel on a drill or even a Dremel sized buffing pad would work good with some green compound.

    I have a mushroom shaped one smaller than a golf ball that works good.
    http://www.amazon.com/SE-Polishing-Mushroom-Shape-CBM202S/dp/B001BNTIRG/ref=sr_1_3

    If that fails Novus 3 and a cloth shines metal up too.

    #3 9 years ago
    Quoted from KloggMonkey:

    The tilt housing looks like it will fit in and ultrasonic and then the tumbler.
    OR
    A small buffing wheel on a drill or even a Dremel sized buffing pad would work good with some green compound.
    I have a mushroom shaped one smaller than a golf ball that works good.
    amazon.com link »
    If that fails Novus 3 and a cloth shines metal up too.

    The part is already clean and free of rust. I thought an ultrasonic cleaner only attacked gunk on parts, not tarnish.

    I have a bench grinder I've been using with a buffing wheel, and while it shines the metal up a bit, it doesn't seem to do anything about the grey splotches on the surface.

    If sanding is the only option here, I'd be very nervous about sanding with a dremmel. Are there any other options?

    #4 9 years ago

    I use C-L-R dilluted with 70% water and a brass bristled "detail" wire brush. It does not scratch the metal and gets in the hard to reach areas. Shines that metal back to like new.

    #5 9 years ago
    Quoted from KenLayton:

    I use C-L-R dilluted with 70% water and a brass bristled "detail" wire brush. It does not scratch the metal and gets in the hard to reach areas. Shines that metal back to like new.

    There's no surface rust or gunk on the surface of the metal. The grey coloring is in the metal itself.

    The whole process I went through so far: cleaned it with simple green, soaked it in rustoleum, washed it off, stuck it in the tumbler for a day, sanded it down, and put it in the tumbler again.

    #6 9 years ago
    Quoted from ForceFlow:

    The grey coloring is in the metal itself.

    Are some areas of the part shiny while others are dull grey? Perhaps there was a coating/plating that has worn off in some areas?

    Maybe clean is all there is to get unless you get it coated/plated/painted/etc. Which part are you trying to shine up?

    #7 9 years ago
    Quoted from KloggMonkey:

    Are some areas of the part shiny while others are dull grey? Perhaps there was a coating/plating that has worn off in some areas?
    Maybe clean is all there is to get unless you get it coated/plated/painted/etc. Which part are you trying to shine up?

    If it had any coating/finish, it's probably long gone because of age, abuse, and my sanding attempts. The dull grey areas were from where there was rust/corrosion/gunk.

    I'm working on the tilt housing.

    Once I finish with it, I was going to coat it with Ballistol then possibly also carnauba wax. I've seen vid mention he coats his parts with clear, but I don't have the equipment or space to deal with clear coating yet.

    #8 9 years ago

    A lot of auto restorers use wax to seal and rustproof metal parts after cleaning. The high-end solution is RPM (Rust Prevention Magic) from ECS Automotive, which has passed a 1,000 hour salt spray test. It requires a little work to apply since you have to heat the item with a heat gun before applying it.

    Everbrite has some pretty good one part clear solutions.

    #9 9 years ago

    It's good to have different types of tumbler media, or multiple tumblers, even if it's multiple batches of crushed walnut or similar. What I have done, is used the tumbling media triangles to knock down the heavy stuff, then dry walnut media, then use an auto chrome/aluminium liquid polish added to another batch of walnut media for the final polish of parts like brass or plated parts. Then you can wax the parts after too.

    #10 9 years ago

    My shooter knob was that dull grey till I worked on it with the green compound and that buffer. Now its mirror like.

    Quoted from ForceFlow:

    Once I finish with it, I was going to coat it with Ballistol then possibly also carnauba wax. I've seen vid mention he coats his parts with clear, but I don't have the equipment or space to deal with clear coating yet.

    Wax will do fine, not sure about the Ballistol stuff.

    #11 9 years ago

    If your seeing sand scratches its because your changing to a finer paper before you remove the previous scratches. Also try some 800 instead of jumping from 600 to 1200 grit, I usually buff with some white rouge and a round felt buffing wheel, after that I use some automotive paste buffing compound called autosol, makes it look like chrome and seems to help ptotect the finish. RPM is some really good stuff used in the automotive restoration business, they put it on bare metal parts that cant be painted for the fear of loosing points when there cars are judged at car shows.

    #12 9 years ago
    Quoted from terryb:

    A lot of auto restorers use wax to seal and rustproof metal parts after cleaning. The high-end solution is RPM (Rust Prevention Magic) from ECS Automotive, which has passed a 1,000 hour salt spray test. It requires a little work to apply since you have to heat the item with a heat gun before applying it.
    Everbrite has some pretty good one part clear solutions.
    » YouTube video

    $35 for 8oz of RPM? That stuff is *not* cheap. I think I'll have to pass that up.

    What's the difference between one part and two part clear?

    Quoted from HighSpeed1:

    It's good to have different types of tumbler media, or multiple tumblers, even if it's multiple batches of crushed walnut or similar. What I have done, is used the tumbling media triangles to knock down the heavy stuff, then dry walnut media, then use an auto chrome/aluminium liquid polish added to another batch of walnut media for the final polish of parts like brass or plated parts. Then you can wax the parts after too.

    I'm using fine walnut media, and have been putting in some mothers metal polish.

    Quoted from KloggMonkey:

    My shooter knob was that dull grey till I worked on it with the green compound and that buffer. Now its mirror like.

    Wax will do fine, not sure about the Ballistol stuff.

    "Green compound"? What is that?

    Ballistol is used for protecting the metal on firearms without harming/reacting with wood or leather. I haven't used it myself yet, but it looks like it works fairly well.

    Quoted from crlush:

    If your seeing sand scratches its because your changing to a finer paper before you remove the previous scratches. Also try some 800 instead of jumping from 600 to 1200 grit, I usually buff with some white rouge and a round felt buffing wheel, after that I use some automotive paste buffing compound called autosol, makes it look like chrome and seems to help ptotect the finish. RPM is some really good stuff used in the automotive restoration business, they put it on bare metal parts that cant be painted for the fear of loosing points when there cars are judged at car shows.

    I wasn't able to find 800 grit 9"x11" sheets in standard 5-packs. There's a couple 50-pack on amazon, but that's more sandpaper than I'd ever use. Home Depot and Lowes don't seem to carry it. Where can you typically find some?

    Also, I'd just like to reiterate, this gray tarnish does not buff or polish away. I can only get rid of it by sanding.

    Lastly, what techniques should I use for sanding in hard-to-reach places?

    #13 9 years ago

    Before. Rusty near where the ball is. Some rust on top. The whole unit was a dull gray. On the face that was mounted to the wood, it looks like soda spilled down the seem and ate away at the metal.

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    After. Here you can see some of the rough surface inside the bracket where the ball is supposed to be housed.

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    What remains of the pitted area eaten by soda. This area was much bigger before I sanded. I'm not to worried about it since you won't see it anyway. However, I can't figure out why there are two tones of metal on the left side even though I sanded it down.
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    It needs to be sanded again since I let a few stray water droplets land on it.
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    #14 9 years ago

    Try some master formula metal gloss, it works wonders. Check it out on youtube

    #15 9 years ago
    Quoted from ForceFlow:

    I wasn't able to find 800 grit 9"x11" sheets in standard 5-packs. There's a couple 50-pack on amazon, but that's more sandpaper than I'd ever use. Home Depot and Lowes don't seem to carry it. Where can you typically find some?

    Home Depot only has it precut 4x9" in 800

    http://www.homedepot.com/p/3M-3-2-3-in-x-9-in-Imperial-Wetordry-800-Grit-Sandpaper-Sheets-5-Pack-5922-18-CC/202563281

    So if you want uncut sheets you will have to go to an auto paint store.

    Quoted from ForceFlow:

    Lastly, what techniques should I use for sanding in hard-to-reach places?

    Sandblaster makes quick work of any corrosion

    #16 9 years ago
    Quoted from ForceFlow:

    "Green compound"? What is that?

    http://www.amazon.com/Woodstock-D2902-1-Pound-Buffing-Compound/dp/B0000DD35C/

    Although it was $6.18 when I ordered mine, crazy amazon price changes.

    #18 9 years ago
    Quoted from crlush:

    If your seeing sand scratches its because your changing to a finer paper before you remove the previous scratches. Also try some 800 instead of jumping from 600 to 1200 grit, I usually buff with some white rouge and a round felt buffing wheel, [...]

    There is an autozone and advanced auto, and that seems to be about it. I went ahead a picked up the sandpaper at home depot.

    I went through the process of sanding it down again. It still left me with fine scratches in the metal in the direction that I was sanding.

    Quoted from vid1900:

    Sandblaster makes quick work of any corrosion

    It's not corrosion. I'm not really sure what it is. Some sort of discoloration.

    I've had no problem with removing rust and corrosion with simple green, a little scrubbing, and a dunk in some rustoleum. I've had trouble with the discoloration underneath where the rust and corrosion was.

    Maybe I'm not polishing correctly. I assumed that you simple take some polish, put it on a rag, and rub it on the metal until it's not really visible and is no longer streaking.

    #19 9 years ago
    Quoted from ForceFlow:

    I went through the process of sanding it down again. It still left me with fine scratches in the metal in the direction that I was sanding.

    Sandpaper is graded to remove the scratches from the last grade.

    If you sand with 80 and then move up to 120, you are not done with the 120 phase until all the 80 scratches are gone.

    If you leave any 80 scratches, then move up to 220, you are wasting your time, because 220 can't remove 80 scratches.

    Try this experiment on a scrap playfield bracket:

    Sand north to south with 120. Don't press too hard, just let the paper do the work.

    Now sand with 220 but only sand east to west. See how when the final 120 scratch is gone you are "done" with the 220? See the uniform surface when the whole area is 220ed?

    Change the direction of your sanding back to north and south, with each grade change, change sanding direction.

    Now sand out all the 220 scratches with 400, then move to 600, then move to wet 800, 1000, 1200, 1500, 2000 and finally 2500. There is again a uniform look when all the previous grade's scratches are gone.

    Now when you finish with the 2500 grit, on a buffing wheel, hit it with Green Compound.

    You now have a mirror finish that looks like chrome.

    -

    You will be amazed at the results, but better than that, the above exercise will etch into your mind the importance of not leaving any scratches from the previous sandpaper grade. If you rush or skip a step, you get to go back a step.

    #20 9 years ago
    Quoted from vid1900:

    Sandpaper is graded to remove the scratches from the last grade.
    If you sand with 80 and then move up to 120, you are not done with the 120 phase until all the 80 scratches are gone.
    If you leave any 80 scratches, then move up to 220, you are wasting your time, because 220 can't remove 80 scratches.
    Try this experiment on a scrap playfield bracket:
    Sand north to south with 120. Don't press too hard, just let the paper do the work.
    Now sand with 220 but only sand east to west. See how when the final 120 scratch is gone you are "done" with the 220? See the uniform surface when the whole area is 220ed?
    Change the direction of your sanding back to north and south, with each grade change, change sanding direction.
    Now sand out all the 220 scratches with 400, then move to 600, then move to wet 800, 1000, 1200, 1500, 2000 and finally 2500. There is again a uniform look when all the previous grade's scratches are gone.
    Now when you finish with the 2500 grit, on a buffing wheel, hit it with Green Compound.
    You now have a mirror finish that looks like chrome.
    -
    You will be amazed at the results, but better than that, the above exercise will etch into your mind the importance of not leaving any scratches from the previous sandpaper grade. If you rush or skip a step, you get to go back a step.

    I appreciate the detailed instructions, thanks

    I just wanted to confirm--with non-scrap parts, do you still alternate the direction of sanding with each grit change? I've always assumed when re-graining/sanding that the grain should always be kept to the same direction.

    What liquid do you use for wet sanding? I've been finding that if I use water and let it dry or let it sit for more than a couple minutes, it seems to stain the metal and I have to sand it down again. Would WD-40 be appropriate, or since it's acts lubricant, does it protect the metal from being sanded?

    Where do you typically get 2500 grit sandpaper? Heck, where you typically buy all your sandpaper from beyond the standard 60-400 grit that hardware stores tend to carry? Do you have a one-stop-shop? So far, I've had to source them from different stores and amazon. Are there specific automotive stores that carry it?

    #21 9 years ago

    I found a NAPA that seems to carry 2500 grit, but they were out of stock. Sigh.

    Any other options?

    #23 9 years ago

    http://www.sandpaper.ca/

    Canadian Eh, save yourself 10%

    #24 9 years ago
    Quoted from vid1900:

    Autozone or Amazon I guess:
    amazon.com link »

    Seems a bit pricey for a sheet of sandpaper. I would think there would be more than one in that pack, but so far it seems to say only one.

    Quoted from eh97ac:

    http://www.sandpaper.ca/
    Canadian Eh, save yourself 10%

    Huh, I'm surprised that the exchange rate slightly favors USD. I thought it was the other way around these days.

    Overall, I'm a bit surprised at the price of sandpaper.

    Any other sources you can recommend? I feel kind of silly spending so much just on sandpaper.

    #25 9 years ago
    Quoted from ForceFlow:

    Seems a bit pricey for a sheet of sandpaper. I would think there would be more than one in that pack, but so far it seems to say only one.

    The picture shows a box of 50 sheets.

    #26 9 years ago

    I ended up getting the 2500 grit sandpaper at NAPA. Apparently, one of their neighboring stores had it, so they brought some in. It was $1.29 per sheet...oof

    Between home depot, lowes, advanced auto, amazon, and NAPA, it looks like I can get all the different grades. What a treasure hunt.

    So, here's what I ended up with. Nowhere near perfect, but good enough for a first attempt for something living inside the cabinet. The one thing I couldn't figure out is why I kept getting discoloration. It seemed as though as soon as I hit it with water for wet sanding, parts of the metal would turn a dull gray and stay that way. Should I be using another liquid? Or not bothering with wet sanding at all?

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    #27 9 years ago

    Use light oil when wet sanding metal, it will keep the paper from clogging better than water.

    Deep corrosion can show as spotting.

    #28 9 years ago
    Quoted from vid1900:

    Use light oil when wet sanding metal, it will keep the paper from clogging better than water.
    Deep corrosion can show as spotting.

    Would 3-in-1 oil be fine?

    As for the discoloration, it's whole areas, not speckles.

    See the circled area, and also the area below where the ball sits.

    discoloration.jpgdiscoloration.jpg

    #29 9 years ago

    That is a hell of a lot of work and thought for a tilt mech that is unseen

    #30 9 years ago
    Quoted from Atomicboy:

    That is a hell of a lot of work and thought for a tilt mech that is unseen

    Well, being unseen is the whole idea of using it as a practice run instead of messing up on a highly visible part else where.

    #31 9 years ago

    You might be sanding through plating on the metal, so you are seeing spots that are still plated.

    Also, sometimes the area around a weld has changed color due to the metals/heat used.

    #32 9 years ago
    Quoted from vid1900:

    You might be sanding through plating on the metal, so you are seeing spots that are still plated.
    Also, sometimes the area around a weld has changed color due to the metals/heat used.

    Hmm...if that happens, is it better just to sand off all the plating, or leave it and save as much as you can?

    Is the metal underneath more susceptible to rusting?

    #33 9 years ago

    Metal is plated for looks (chrome, gold.....) or for protection.

    If you have to sand or blast to remove corrosion, then the protection has outlived it's usefulness (or was poorly done).

    You can just spray cheap poly from a can to protect in a thin coat.

    #34 9 years ago
    Quoted from vid1900:

    Metal is plated for looks (chrome, gold.....) or for protection.
    If you have to sand or blast to remove corrosion, then the protection has outlived it's usefulness (or was poorly done).
    You can just spray cheap poly from a can to protect in a thin coat.

    Are playfield wire guides, scoops, ramps, etc. typically plated?

    What about for parts that need to remain electrically conductive, like the tilt assembly?

    #35 9 years ago
    Quoted from ForceFlow:

    Are playfield wire guides, scoops, ramps, etc. typically plated?

    Some flat ball guides used to be chrome plated, not so much wire guides or ramps that are usually just stainless.

    Quoted from ForceFlow:

    What about for parts that need to remain electrically conductive, like the tilt assembly?

    Those were probably zinc plated.

    #36 9 years ago
    Quoted from vid1900:

    Those were probably zinc plated.

    Sorry, I was a bit vague with the phrasing of my question--what should I do with a part that needs to remain electrically conductive?

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