# How to clean up the rule in a combination square?



## DonnyBahama (Jun 21, 2011)

I've got a nice Starrett 4-piece combination square that I got a great deal on because it had some rust. I got everything cleaned up pretty nicely with some steel wool, but the rule is discolored and hard to read as a result. If anyone has a good tip for restoring it back to its original luster, I'd appreciate hearing it.


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## donwilwol (May 16, 2011)

I've used a fine wire wheel with good luck.


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## LepelstatCrafts (Jan 16, 2011)

if the marks are indented on the ruler, here is a little trick that I use. Take some black paint and paint the entire ruler. While the paint is still wet, take a paper tower and wipe off the surface gently. The indents / marks should be the only thing that has black paint. Let it dry and your all set.


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## Minorhero (Apr 8, 2011)

If you are trying to remove the discolorations left on the steel rule by the rust then there are 2 things to try. 1 buy some Evaporust and soak the rule for 24 hours completely submerged. The other thing to do is buy some bar keeper's friend and make a paste with it and rub the rule with a green scotchbrite pad.


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## ChefHDAN (Aug 7, 2010)

I've gotten good results with a buffing wheel in my drill press


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## stevenhsieh (Jan 8, 2010)

What Minorhero said


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## gfadvm (Jan 13, 2011)

I would use a 6 or 8" hard cotton buffing wheel with white compound in my bench grinder. Mine wasnt a Starret but I cleaned the rust/black stains off an old square with this technique. Wholesale Tool is my source for buff wheels and compound. The wax in the buffing compound leaves a nice finish and helps prevent future rust.


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## KBX500 (May 21, 2011)

I've had 20 - 25 Starrett combination square sets that I've restored over the years 
for resale or to use myself. I've found that if your going to actually use it for shop 
work, and the blade is really discolored, corroded and/or pitted, you're probably 
better off buying a new blade. The 12" rule with quick reading 32nds & 64ths in 
the satin chrome finish, Catalog # B12R, is $38.50 at Amazon. The satin chrome 
is much easier to read for older eyes. It's also a good time to consider a longer 
blade. Starrett offers 12", 18", 24", 36" and 48" blades in satin and regular finish.

If you're cleaning it up for show, Evaporust is a good product to use, if it's still 
rusty or has rust particles on it. Follow that, if necessary, with a light sanding with 
a fine grit, or a 3M Scotchbrite product or something similar. Then the previously 
mentioned paint tip to finish it off.

Starrett's #32 catalog has lots of good info in it, plus all their products, of course. 
I ordered another one recently and had it in 3 days.

Keith


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## BentheViking (May 19, 2011)

After reading this post I got inspired to try to clean up an old very rusty combo square rule today. Sat it in a bath of CLR for a few hours and came back just had to use a wire brush to finish off a couple of extra grimey spots but most of it came off just sitting in the chemical. Just have to wonder how long it will stay clean


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## WayneC (Mar 8, 2007)

Use a little wax or oil on it to keep the rust at bay.


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## oblowme (May 20, 2011)

This is REALLY not for the faint of heart so if you do not feel comfortable or have a single doubt in your mind about it stay way away from it- Muritic Acid will eat up any corrosion in a big hurry, it's the active ingredient in allot of 'rust removers'. Mind you it's not one bit user friendly and can be very dangerous stuff if you don't know what you are doing.
Should you want to screw around with it there are a number of things you need to know-

1- Not only will it eat up rust it will eat you up too, eye protection (or better yet a face shield) rubber gloves (preferably the long gauntlet type) and a respirator are mandatory.

2- Only use it outdoors, the fumes will literally take your breath away, stay up wind at all times. Do not store it anywhere near anything you'd like to remain corrosion free, the little bit of fume that escapes from an unsealed container will go to work on any bare metals near it. Be absolutely sure children can not get to it at any time.

3- Keep 2 containers of water/baking soda solution at hand, (at least a half cup of sode in 5 gals of water) the soda neutralizes the acid immediately, one bucket in case you get any on you and the other to kill the action of it on whatever you are cleaning, wiping it off will do no good, you have to kill it. Also be aware that if allowed the acid will build up in the dunk bucket enough to over come the soda and therefore will need to be changed.

4- Be prepared to apply oil, grease, wax or what have you to the cleaned metal as it will start to rust very quickly, I know it doesn't make sense, but that's what happens.

5- It does not work through grease or finish coatings very well.

6- Wear old clothing, just like with battery acid they can come back from the wash with mysterious holes in them.

7- Work with it a little at a time, dip the piece a minute then wash it off and be sure to get all of the soda off. Be sure you do not allow the undiluted soda and acid to come in contact with one another, the reaction can be quite violent. Do not drop a piece in it and walk away, given enough time whatever's left when you get back will be hotter than the hinges of modern day hell and probably useless.

8- The only safe containers for it are plastic.

9- It can be diluted with water to make a weaker solution, more water less action but safer to work with.

Now with that said I do not recommend it to anyone, use at your own risk. It works very well and will remove every last speck of rust right down to the white metal. I learned how to use it in doing auto body work. 
A set of lathe tools that came to me with an old Delta that were so rusted it was kinda hard to tell what they were, 20 minutes in the acid and they were near new again.

Don't bother coming after me about how dangerous this stuff is, I think I stressed that about as far as it gets. Before going into it I suggest Googling Muritic Acid and get all the info you can find.

One more time- If you have any question in your mind about any aspect of this DO NOT go anywhere near it.


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## BlankMan (Mar 21, 2009)

I third what Minorhero said. I keep a few gallons of Evapo Rust on hand, buy it from HF when I get 25% off coupons.

Careful about soaking it for 24 hours though, I do that too that but sometimes the piece will get a black coating on it that takes some work to then get off.


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## DonnyBahama (Jun 21, 2011)

Thanks for all the great suggestions, everyone! I have some Barkeeper's Friend so I'll try that first. (Thanks, Minorhero!) I also have hard cotton buffing wheels for my Dremel tool so I may give that a try. (Thanks, gfadvm!) I'd never heard of EvapoRust before but if HF has it (thanks, BlankMan!), I'll pick some up. The Muritic Acid sounds a little scary. Worst of all, it sounds like there's a good chance I could FUBAR my rule, so I think I'll skip that technique. (But it was an interesting read - thanks, WoodRMe!)

@Mike - That's a really cool trick! I may decide to do that no matter what else I do. I wonder if I could put it on with a foam brush, then remove the excess with a clean/empty foam brush?

@KBX500 - I'm pretty broke right now, so replacing the rule isn't really an option - but it's cool to find out that Starrett offers them in several other lengths! I ordered a Starrett catalog - thanks for the tip!

@BentheViking - CLR… is that the stuff that's sold primarily as a lime remover?


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## Belg1960 (Jan 3, 2010)

Guys, I searched for how to clean a rusted square and found this old thread. I just wanted to add my results and one more option. I used a product called Flitch metal polish, and some abrasive pads. I experimented on a framing square here are my results. I cleaned it first with some mineral spirits to clean the surface rust and dirt.


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## bold1 (May 5, 2013)

I use a wire brush on the surface, then baking soda in my sand blaster to clean the indents and spray with white enamel, that I wipe off the surface. I used to use black but it doesn't show up as well as the white. I finish by using a good car wax after the paint is dry.


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## macgee (Dec 1, 2013)

I've tried several different ways to clean my rulers and squares. So far the best is using double stick carpet tape & sanding blocks.

Taping the ruler onto a flat surface, then using klingspor Sandflex sanding blocks (coarse & fine versions) to sand/clean up the surface. They work very well and makes cleaning steel surfaces almost a pleasure. As mentioned in earlier posts Starrett rulers have pretty deep engravings so your rather safe cleaning up the surface without damaging the ruler marks.

I finish the ruler off with Maas metal polish creme, awesome stuff and highly recommend it and should be in everyones cleaning supplies. Using the metal polish removes oxidation and leaves a clear coating after polishing to help it from further tarnishing.

The biggest problem is pitting, almost all of the older rulers I've come across has pitting to some degree. You'll spend most of the time removing the pitting. I definitely will use the coarse version of the Klingspor block the most. I think I prefer the more satin finish of the coarse block than the more mirror like finish of the fine klingspor block. I found using the sanding blocks to clean the ruler the best. I try to avoid using chemical cleaners as they removing the painted marks on the ruler and they don't remove the pitting.

Three problems with cleaning old steel rulers:

1. Most likely the bad pitting can not be removed without removing/damaging ruler markings.
2. While sanding/cleaning the ruler, you will remove to a degree some of the paint in the markings. Highly recommend to apply black paint and wipe off to the ruler after sanding.
3. I don't like the shiny chrome like finish you get after refinishing rulers. There very shiny and pretty to look at but seem harder to read because of glare but substantially better than a old dirty ruler.

My favorite ruler and square is "Products Engineering Corporation" (PEC) satin rulers and squares, very easy to read and very easy on the eyes. You can buy a new 12" replacement blade on ebay for about $20

I hope this is useful for other members.


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## macgee (Dec 1, 2013)

I forgot to say that you will only need to use two small pieces of double tape otherwise the ruler maybe quite difficult to remove from table.

This is also a must have, Goof Off is excellent for removing grime and residues. Spraying this will help remove the ruler from the double stick tape and will remove the residue, just Don't let it sit for very long otherwise it will remove the paint from the ruler. It's also exceptional for cleaning table saw blades (use gloves), let it soak for 15mins.


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## waho6o9 (May 6, 2011)

Thanks Macgee!

MAAS metal polish is on it's way.


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## macgee (Dec 1, 2013)

Your welcome wahoo,

Get back to us and let us know how well it works for you.

I really also recommend trying out the Sandflex blocks, they have small shavings of metal in the block. They work really well on table saw surfaces, jointers and drill press tables. I just used the blocks this morning to clean up a newly acquired Starrett protractor, it was rusted, unreadable and unusable before cleaning it.


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## darthford (Feb 17, 2013)

Evaporust or just buy a Starrett satin chrome replacement rule, far superior.


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## waho6o9 (May 6, 2011)

Will do Macgee!

http://www.woodworkingshop.com/product/sa99996/

Sanding blocks on the way as well.

Looks like goof off will be had when time permits.


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## Knothead62 (Apr 17, 2010)

Belg1960, are you referring to Flitz? If so, it can be bought at any good restaurant supply company. I used to sell it to restaurants for keeping silver and copper chafing dishes clean and polished. It is also a preservative. Comes in a small tube or a larger can.


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## Belg1960 (Jan 3, 2010)

Knothead, I guess I did spell it wrong but that is the stuff. I use it and really like it. Pat


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## waho6o9 (May 6, 2011)

Many thanks Macgee!

I found out my favorite combo square is a Stanley #21 EM after using 
the coarse block for about 6 - 8 minutes I think.

It's really incomprehensible how well those sanding 
blocks worked and the minimal time it took to remove decades
of oxidation and tarnish etc….

I wanted to use coarse, medium, and then the fine, turns out the fine
block wasn't needed. Amazing. I had to use Oops cause they didn't have 
Goof Off and the results were similar.

The results were remarkable:









I'm looking forward to using all the blocks and the MAAS polishing
compound as well:


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## macgee (Dec 1, 2013)

Hey Wahoo,

Glad my recommendation was helpful.

Another cleaner I can recommend is Evapourust (biodegradable), you can find it at Autozone's. It's really works with stuff that's rusted and hard to reach (like the inside of socket sets), cheap vinegar is also a good alternative (Submerge the whole item for best results for 12+ hrs). The only thing with both is that it can cause a darkish patina to the metal. I just used it on a vise and then used the hand blocks and the dark patina came off afterwards, it's work well and now have a shiny rust free vise.

I also strongly suggest putting paint on afterward on the blades, then wipe it off so there's only paint in groove markings and the surface is clean, it's really easy to do. It will make a huge difference making it legible again. Im also refraining from using the medium and fine blocks. The rulers get too shiny making it hard to read and I like the satin finish that the course block leaves and maybe not even polish it. I do use the fine block to finish the square head, knobs and other parts.

While using the MAAS polish, only apply a very thin coating and let it dry (not long), you benefit the most with two wipe downs. The first wipe removes most of the excess polish, then use a second clean cloth and really wipe the item, this is when you get the best finish. The polish really work's well on table saws surfaces, it leaves a very smooth finish and wood slides very well over it. Anything with chrome benefits really well. I even clean my watches, bike parts, chisels and cuffs links…..etc with it.

Just be careful using the polish and not to go over with printing, stickers, thin paint and labels….etc; it can quickly remove light paint and lettering. Sharpie pen marks will come off immediately.

Cheers!


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## exelectrician (Oct 3, 2011)

MSC industrial supply has brand new 12" SPI brand rules for $18.29 the 24" is $28.15 
I am sure there a many more suppliers out there of these common rules.
Once you start sanding a rule it will NEVER be dead straight again. So why waste all that time and effort to get an inaccurate tool? Just does not make sense, unless of course want to put it in a glass case and not use it.


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## JohnMcD348 (Jan 10, 2014)

Another option you might try, and cheaper since you probably already have it around the house is, White Vinegar. I used it on some old rusty tools some time back after reading about it and was quite surprised. It won't probably work as quickly as some of the commercial cleaners but it will take the rust off and cleanup is finished with plain old steel wool.


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## macgee (Dec 1, 2013)

exelectrician:

First of all, some people don't like throwing away there old favorite tools. Why not try to save your grandfathers square? This method of cleaning applies to all sort of things in a shop.

2nd: You only need to clean the top and bottoms, I'm going to go waaaay out on a limb and say that the majority of people do not use the engraved areas as a straight reference area and if cleaning is done properly (described above) with some common sense it has no bearing on the area that is used as a reference.

Third: I have a room full of measuring equipment that includes digital dials and a surface plates…etc. I've checked the blades and there is under a .0015-.002" of change over 12" before and after, if anything the edges are improved and still totally within the required tolerances for fine wood working. Of course if the edge is badly pitted or dented then you have problems.

If you want to buy a new blade or square head I suggest buying a PEC (USA made), do a search on line and see about the debates between, PEC, Starrett and Mitutoyo. The good part is you can buy a PEC for way less than the other two.

Here's a really good and cheap source for combo squares and blades. 12" square for $24.
http://store.harryepstein.com/cp/Squares/7131-4R.html

Have a good evening


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## mathscienceguy (Jul 29, 2014)

Thanks, macgee, for an excellent post!


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## comboprof (Aug 26, 2013)

Evapo-rust is amazing and safe for the environment and wood. I saw an experiment that shows among the available products it is in the long run cheapest, because it can be reused over and over again longer then other products. It works fastest when warm. I.e. use it in direct sunlight or heat it on say a stove. But it will still work well at 65 degrees. For the squares I've done. I soak it it for a few hours in evapo-rust rinse with water, dry it with a towel, and then hit it with a wire wheel or 400 grit wet/dry paper. I repeat all of this if necessary. I've used gun blueing instead of the black paint to raise the numbers. but maybe the black paint is easier.


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## paulm12 (Oct 31, 2014)

as a beginning woodworker, thanks much. I am going to try this on my Dad's old square, has been hanging on the wall for 10 years, waiting for me to get going.


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