Rust on base of otherwise nice 12" Starrett 98 Level

As part of a shop buyout, I purchased a 12" Starrett 98 level from a guy. I don't have much in it, but the base of the level has some rust
on in. Not big red flakes, just dark brown discoloration. Still feels pretty smooth.
I need to stop it before it gets worse, and really, I'd like to get rid of the rust altogether. The problem is my normal methods of rust removal (Ospho, bead blasting, wet sand blasting, and grinding) while effective, are primitive and would render the level useless.
How would you folks stop and/or remove the rust gently?
Thanks! Dave
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LowEnergyParticle wrote:

If it were mine, I'd put a dab of Knorrostol on a rag and wipe it over the stain, then wait about 30 seconds and then just rub it off. Or maybe I'd use a 3M deburring wheel on the stain. Those 3M wheels are just great, not cheap tho.
GWE
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I'll second the Knorrostol. I think it's made by SPI and McMaster-Carr special ordered it for me a few years ago. About $15 for a tube that is still in use.
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Simichrome is a similar product that's also very good. Smear a little on a piece of copy paper placed on a surface plate, then gently scrub the base of the level on the paper. This will remove light rust with minimal chance of damaging the surface.
Auto polishing compound, or even toothpaste, would also work in a pinch, but the Simichrome really does seem to be much better for this sort of thing.
Ned Simmons
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I'd suggest phosphoric acid, followed by a good hot water rinse, being careful to rinse only the necessary areas, then lap the level on a good and proper lapping plate. That should restore the base, and, if not, grinding on a decent surface grinder may be in order. Unless the rust is perfectly uniform, it has already done damage, so stopping it alone isn't good enough if you expect the level to perform to its capacity. Besides, you'll probably be surprised to find it's not flat, anyway. They typically are not. I had to rework mine, and it was purchased new. I'm not convinced Starrett does anything to relieve stress---which happens slowly over a period of time, yielding a bowed base.
Harold
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On 3 Dec 2005 22:21:49 -0800, "LowEnergyParticle"
Electrolysis (Google) or wet pad electrolysis if you can't safely immerse the thing.
Don't use phosphoric on measuring instruments, because a small pit is better for accuracy than a pimple.
Rust on steel doesn't need to be "stopped". Keep it dry and it won't rust. Keep it damp and it will start again, no matter what state it's in. The catalytic action of rust is real, but it's really just affecting the rate, not its presence.
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Depending on what you need the level to do... If not too critical, use a belt sander and give it a coat of paint with a brush. If critical, sell it and get a new one, or send it out and get it ground and calibrated.
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On 3 Dec 2005 22:21:49 -0800, "LowEnergyParticle"

Wipe it down with a good stiff piece of canvas, using a ittle bit of Kroil, let sit for an hour or so, scrub it again, then use LPS. To make is shiney again..means you have to remove metal.
How much depends on how shiney you want it. Shrug. learn to live with discolored steel. As you proceed in the hobby..you will get lots of it.
Just my .002 worth.
Gunner
"Pax Americana is a philosophy. Hardly an empire. Making sure other people play nice and dont kill each other (and us) off in job lots is hardly empire building, particularly when you give them self determination under "play nice" rules.
Think of it as having your older brother knock the shit out of you for torturing the cat." Gunner
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<...>

1/5 of a cent? Have you recently discounted your opinions, Gunner? :-)
-- Jeff R.
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wrote:

I consider each drip and drab to be priceless when uttered by my nimble fingers!
However..the market prices for opinions is at a low at the moment, shrug..(Nasdaq: RANT)...so I have to go with economic forces. I think its a result of the Katrina issues. On paper, I was very rich, until the slide.
Gunner
"Pax Americana is a philosophy. Hardly an empire. Making sure other people play nice and dont kill each other (and us) off in job lots is hardly empire building, particularly when you give them self determination under "play nice" rules.
Think of it as having your older brother knock the shit out of you for torturing the cat." Gunner
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wrote:

Remove the vial holder and screws. Use electrolytic de-rusting for the base of the level. You will not be able to accurately re-scrape the involute groove in the base but you can re-scrape the flat part of the base if it is severely marked. Clean and oil the base then, after re-assembly, re-calibrate the level by adjusting to get an equal reading when rotated 180 degrees on a fairly flat, stable surface such as a surface plate or the table of a mill.
Mark Rand RTFM
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I'd take it off with scotch-brite. It should get the rust without damaging the surface.
LowEnergyParticle wrote:

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LowEnergyParticle wrote:

Evaporust. Pour a little in a shallow tray. Set the level in it. Come back in 2 hours. Wipe clean, oil to taste.
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Thank you all very much for your replies!
I ended up using a combination of several replies: I used a "fine" grade 3M Roloc disc on a die grinder with the air set to only 15#, and Kroil as a polishing lube. The Roloc discs supposedly won't remove metal. Kroil is great for rust busting, and the combination of the two worked well. I finished off with a polishing rag and LPS-3. It now looks pretty, and I don't think I damaged the level.
I was thinking about what Gunner mentioned in his post above, about learning to live with rust. I think that's true; especially if you're in a rust-inducing environment like I am. I think it helps your sanity, though, if you draw a strict line, like: "no rust on measuring instruments or ways", or whatever is important to you. Then you can look at the motor case, or the gantry, or the whatever, and say, "Yeah, it looks like hell, but man, my (insert your favorite here) is clean as a whistle." Ridiculous, but what the heck. It's kind of like remodelling your house, where you don't tear up everything at once. Keep at least 1 or 2 rooms untouched so you have someplace to go to regain your sanity.
By the way, thank you for mentioning "Evaporust". It looked interesting, and I've ordered a quart to try.
Take care, and thanks again for the help!
Dave
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LowEnergyParticle wrote:

That tool came in a nice mahogany box. I suggest you wipe a thin sheen of light oil on the ground surface and then put it away in its box. I throw a desiccant pad (keep 'em when they show up in shipped items) in and I have never had any rust on my 12" Starrett level.
GWE
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Grant Actually if you check the wood box is optional on the 98's. It was 10 years ago when I bought my last one. lg no neat sig line

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years
Yep! My 98 is an 8" model, bought new, with one of those *super nice* cardboard boxes. I store it in a wooden box, though. My Gerstner. No rust problems inside, not even when the box was stored for 4 years in one of our containers.
Harold
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    [ ... ]

    Mine came in a similar box, with a sheet of VPI paper in it, which so far has done an excellent job of protecting mine.
    Enjoy,         DoN.
--
Email: < snipped-for-privacy@d-and-d.com> | Voice (all times): (703) 938-4564
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The one I purchased used a few weeks ago (rusty when I bought it) regrettably did not come with a box of any sort. I don't know whether it was originally sold with the mahogany one or not.
Here's a trick that has worked well for me: put a charcoal briquet wrapped in a layer of cloth in each drawer of your toolboxes. The cloth is just to keep the dust contained. Charcoal is a good desiccant, and of course it's very cheap. I change them every 3 months.
Thanks again for all the help! Dave
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    Based on some other followups, the box was an optional item. I haven't checked the catalog on it, but I do remember the case being an optional item on may of Starrett's tools, with the red cardboard box being the default. (It probably doesn't make much difference if you intend to keep it in a toolbox anyway.)

    Another trick is to put a small piece of camphor in each drawer. It acts pretty much like the VPI paper to protect tools in that drawer.
    It very slowly sublimes, so it needs to be replaced from time to time.
    Enjoy,         DoN.
--
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