I have an old carpenter's square that is rusted. It's not so bad that the numbers on it are corroded or damaged, but the lack of contrast is such that I can't read it unless I'm in direct sunlight.

What is the best way to restore the surface of the square such that I don't erode the information stamped in the surface, but can still read it?

Thanks for your suggestions.

A

Oshpho will "eat" the rust. I have a gallon jug of the stuff in the hangar, if you want to come by and use some.

A guy who owned a chain of auto body shops turned me on to this stuff; we use it for dealing with rust in the rental machines.

quote:

Originally posted by V-Tail:
Oshpho will "eat" the rust. I have a gallon jug of the stuff in the hangar, if you want to come by and use some.

A guy who owned a chain of auto body shops turned me on to this stuff; we use it for dealing with rust in the rental machines.

This is probably your best bet, to use Ospho. Ospho also converts the rust so that it stops rusting, and can be painted over if you wish to do so.

If the marks are stamped or etched, sandpaper (80-150 grit) or CLR should take the rust off pretty easy.

I've removed rust from squares and other tools with by soaking them overnight in muriatic acid. It's generally near paint stripping chemicals at the hardware store. Another approach is to set up an electrolysis tank with an old battery charger or power supply. That takes a bit more time but works as well.

What I haven't figured out yet is how to paint the engraved numbers and measurement marks to get clean results.

I have a couple of ladder stands in the woods (for hunting) that have some rust. How would I apply the Oshpho? Is it something I could put in a spray bottle or does it need to be brushed on? (By spray bottle I'm talking a hand held bottle like you'd see with a stain remover for laundry or like you'd see with a window cleaner)

One review on Amazon says it needs to be washed off before you can paint over it - is that correct?

What happens if I don't paint over the top?

Ospho will work wonders.

I used a yellow crayon and "scribbled" on the marks of my old square. Then I wiped the excess off the surface of the square. It wasn't permanent but made the lines really easy to see.

quote:

Originally posted by SR:
I have a couple of ladder stands in the woods (for hunting) that have some rust. How would I apply the Oshpho? Is it something I could put in a spray bottle or does it need to be brushed on? (By spray bottle I'm talking a hand held bottle like you'd see with a stain remover for laundry or like you'd see with a window cleaner)

One review on Amazon says it needs to be washed off before you can paint over it - is that correct?

You can use a spray bottle to apply the ospho.....brush is the preferred method for larger areas. It should be rinsed off before painting.

quote:

One review on Amazon says it needs to be washed off before you can paint over it

On our rental equipment, we use a brush to paint it on the rusty area, let it dry, then use a wire brush to clean it up a bit, then apply paint (Rustoleum).

Does the Ospho leave a black/brown surface, or a shiny surface?

Yes, ospho converts the rust and it looks black.

I’d go with evaporust...it doesn’t leave the black converted rust.

https://evapo-rust.com/

Something like evapo-rust or naval jelly is what you want, to remove the rust and return the surface to bare metal so the numbers stand out.

Rust remover, not rust converter. (Rust converter chemically turns the rust into dark gray/black primer, which will obscure the numbers.)

You'll just need to keep that area oiled/greased/waxed afterwards, to prevent the rust from re-forming.

Thanks for all the information, everyone. I'm looking for the outcome RogueJSK mentions. I'd like to have contrast between brighter metal and darker lines. I will likely do naval jelly, a light polish, black paint into the markings, and then wax when it's all dry.

I’m just wondering if, once you’ve got the rust off, would spraying with a clear coat be effective?

I’m wondering because I’ve never sprayed metal without a primer coat and color first before clear coat.
.

quote:

Originally posted by OKCGene:
I’m just wondering if, once you’ve got the rust off, would spraying with a clear coat be effective?

I’m wondering because I’ve never sprayed metal without a primer coat and color first before clear coat.
.

When you buy them new, they come with a clear lacquer or clear plastic coat which prevents rust for some time. Eventually the finish crazes, and you get spidering rust all over which will eventually need to be stripped and cleaned up.

quote:

Originally posted by OKCGene:
I’m just wondering if, once you’ve got the rust off, would spraying with a clear coat be effective?

I’m wondering because I’ve never sprayed metal without a primer coat and color first before clear coat.
.

Ospho preps the metal like a primer would, so you can paint a clear coat directly after you do the Ospho process.

Possibly sand it all with 120 grit with an orbital (DA). The stamped markings should contrast the freshly sanded areas and stand out well. Then clearcoat.

Otherwise, evaporust and a maroon scotchbrite. If you don't soak it, which is hard anyway because of the size. Scotchbrite dipped in evaporust is pretty effective. Would still need a clearcoat to protect from rust.

soak in coke. Rinse and repeat until rust is all gone. Might take 3-5 times.

quote:

Originally posted by Hamden106:
soak in coke. Rinse and repeat until rust is all gone. Might take 3-5 times.

^^^^^^^^ That coke is == as in Coke a cola the soda pop drink. ........drill sgt.

Coke+1. That's where I was headed. Then see where you're at. Maybe wipe it down with some breakfree when done and buff it a bit. I'll bet you're good and respectably functional by then. Coke is my favorite acid. Slow, but safe.