Slip gauges - dealing with patches of rust

I have just been given a set of imperial slip gauges that have been sitting in a garage for some years. A number of the gauges are slightly pitted with rust.

Any suggestions for getting the gauges back to a state where I can at least use them for setting and testing measurements accepting they may not be good enough to be part of a stack.

Scotchbrite (or B&Q's cheap imitation of it) and WD40 works on my lathe chuck and slide tops if rust spots appear. They disappear as if they'd never been - visually at least.

Edited By Mick B1 on 16/03/2020 11:49:12

Any abrasive is likely to remove material, but since we are unlikely to be working to hundredths of a thou, in a temperature and humidity controlled environment, it probably won't matter.

The object is to remove any rust standing above the hardened surface. Rust pits below the surface will not affect the dimension, although unsightly.

They may now be incapable of being wrung together, but should suffice for most purposes.

Just use the finest grade of Scotchbrite that you can get, which may be red, I think.

Howard

I was given an old set of slips, unfortunately poorly stored so quite rusty in some places, I soaked them in citric acid for a few days which got rid of the rust, left it with an overall grey colour then went over them with fine scotchbrite and WD40.

Still pitted but the pits are below the working surface and the rust has all gone , they are good enough for anything I'm likely to do, I find them very useful, just used them to set up loco slidebars, maybe if they were pristine I might be more reluctant to use them!

Dave

My workshop is definitely not temperature controlled!

Before going as far as an abrasive like Scotchbrite, the motorcyclist's trick for removing rusts spots from polished chrome, is to use crushed aluminium foil and Coke ( or a brand equivalent that still has a bit of phosphoric acid in it.)

I've soaked rusty stuff in normal vinegar, which seems to turn the rust black, and soften it; might take several hours, or even overnight, so it will be hard to monitor for possible damage.
I've personally not had it affect the parent metal.
One than then just brush it with a soft stainless brush under a hot tap, and immediately spray with a water repellent such as WD 40
The hot tap means it will self dry after a wipe with a towel, as re-rusting starts very quickly.

N.B. I've never tried either of the above with slip gauges.

Bill

Leave to soak in molasses (Black Treacle) for a while.

I have used this successfully on rusty camera parts - aperture blades

Nick

Nick. Interesting - what does molasses do to the blueing/blacking on the iris blades?

For the slips, I suppose the safest and most effective rust removal method is electrolytic.

I would try a brass brush and oil, but make sure the brush is real, not plated steel.

I was curious to see whether the top-right-hand-of-home-page search would be defeated by the typo in the thread title - I think it does. Could it be corrected for the benefit of posterity?

Thank you.

I meant to post in the current thread rather than this correctly-spelt one.

Edited By ega on 17/01/2022 11:46:45

Edited By ega on 17/01/2022 11:47:07

Edited By ega on 17/01/2022 11:49:56

I use electrolysis to remove rust. This doesn’t seem to damage the underlying material either and washing soda is very cheap in the supermarkets.

Definitely +1 for using chemical as opposed to mechanical or manual (Abrasive ) means of removal.

Howard