Cleaning rusty nuts

[Triumphman]

I've got some nice vintage nuts and bolts for use on a job, they're not wasted just got surface rust and oil on them etc what can I dip them in to help clean them up?

 

[chunkolini]

Give them a scrub with soapy water and a soak in citric acid. This will remove the rust, will it remove the plating as well?

 

[AndyStobbs]

Can't be much in the way of plating on them if they've gone rusty in the first place.

 

[Burdekin]

Buy a container of concrete cleaner from B&Q. Make sure it's the one with hydrochloric acid and the B&Q one is the same as the Cementone one but is cheaper. Just check them every 10 or 15 minutes. It works a treat at removing rust.

 

[Sean]

tin of black treacle( molasses) in a 4l tub of warm water put the bolts in for a couple of days and itll all turn to black sludge - wont harm any paint or plating.

 

[CompoSimmonite]

White vinegar works fine for surface rust.

Paul H

 

[Ducky]

Bilt-Hamber Deox-C solution works well.

 

[MattF]

Black treacle or electrolysis, (preferable option), are the two methods which will cause none or least surface damage. Any form of acid will leave a slightly rougher and likely pickled looking surface.

If you do go down the hydrochloric path, make sure you keep that stuff in a well sealed container. It'll rust anything within spitting distance if it gets into the atmosphere, and as with any acid based method, rinse the parts in boiling water afterwards.

 

[hotrodder]

Any form of acid will leave a slightly rougher and likely pickled looking surface.

Many organic acids won't... citric, acetic (vinegar), oxalic (rhubarb), tannic and probably a few others all work in the same way as molasses/black treacle. Chelation, they eat rust but won't touch good steel.

The resized pic hides some of the detail and i've not a before that shows how rusty it was but this Dickson tool holder spent an hour or 2 in hot citric*, the colour difference on the top is from areas that were rusty enough to pit the steel i.e. all the rust has gone but the pits remain. Note that the origional machining marks are still visible on the sides and back



Citric is (one of/the main) active ingredient in Bilt Hamber Deox-C and many other commercial products along with probably some surficants to speed things up and (in the case of gels) a thickening agent. Hammerite/Kurust is Tannic acid based

* Boil kettle, add citric acid powder and leave for a few minutes/until it stops fizzing. With the inside of the kettle now spotlessly clean pour into another container covering the tool holder or whatever is rusty. Once cool/when there's no longer little bubbles cling to the parts remove, tickle with a wire brush to remove the residue and wipe with an oily rag. Citric acid can also be used to passivate stainless, clean and brighten aluminium, descale all sorts of things for those us that have hard water

 

[MattF]

Many organic acids won't... citric, acetic (vinegar), oxalic (rhubarb), tannic and probably a few others all work in the same way as molasses/black treacle. Chelation, they eat rust but won't touch good steel.

They will. What metal they're used on can make a vast difference to finish. The likes of that tool post would come out fine. Try the same solution on, say an old iron or cast part, however, and you'll find the finish is worlds apart. Acid isn't fussy. It reacts to some degree with any material available.

I've tried citric acid and still use it for odd jobs. I also have a basket of old pieces which it's left a bloody terrible finish on too, hence why I'm very selective about what it gets used for these days.

Just noticed one thing you mentioned, namely aluminium. That's one thing I've never tried citric with, so far. Does it remove heavy oxide from aluminium?

 

[hotrodder]

Being pedantic i did say will eat rust but not good steel As you say different metals are different, if i think a part i've got to repair is magnesium i use vinegar to test- can leave steel in vinegar for weeks but it reacts quickly with mag fizzing away producing hydrogen

Don't think citric will be so good at removing heavy Al oxide but it's not something i've tried either... i tend to use it as a cleaner/brightener rather than something to soak really manky ally in. Treadplate is the usual suspect due to the textured surface. I think one of the issues of soaking an ancient ally part is that the citric will react differently with the alloying elements- kinda like how a strong alkali cleaner would be followed by desmutting, especially with alloys containing much Cu and/or Si

 

[MattF]

Being pedantic i did say will eat rust but not good steel

That was a sneaky get out.

Don't think citric will be so good at removing heavy Al oxide but it's not something i've tried either... i tend to use it as a cleaner/brightener rather than something to soak really manky ally in. Treadplate is the usual suspect due to the textured surface. I think one of the issues of soaking an ancient ally part is that the citric will react differently with the alloying elements- kinda like how a strong alkali cleaner would be followed by desmutting, especially with alloys containing much Cu and/or Si

Suppose it might be worth a suck it and see session then. At least then we'll know for future reference. Have a few ally bits which have done the usual due to moisture exposure, but not too fussed on going the caustic route. I'll try a piece in the citric and see how it fares and post back. End of the day, it doesn't really matter if one of the parts ends up knacked, so I'll give it a whirl. Never even thought to try it 'til you mentioned though.