Thread: Rust on Lathe parts.

Originally Posted by nearnexus

Well guys, my lathe purchase came off and if you look at the tool gloat thread you can see what I am going to de-rust pretty soon.

This is awesome.

Rob

That is great. We will be waiting for the restoration thread.

Dean

Oldneweng, rust stains left on machined cast iron surfaces, after rust removal, may present a problem to you if you are concerned with aesthetics.

Hand wheels etc are easily polished to remove blemishes. A different story for the bed.

This was a topic I dealt with some time ago, without satisfactory suggestions.

My lathe bed is now fully painted, and I would like to remove the rust stains, if possible. Can't use any acids now in case they attack the paint.

The photo below just shows the stains after rust removal. It's now fully painted.

Does anyone have any further suggestions?

Ken

Originally Posted by neksmerj

Oldneweng, rust stains left on machined cast iron surfaces, after rust removal, may present a problem to you if you are concerned with aesthetics.


Does anyone have any further suggestions?

Ken

I had a play around with a couple of things out of the laundry cupboard this morning:

Spirits of salts (soldering solution). No go

Tarn-Off. Yes this worked OK - this has sulfamic acid in it - used a toothbrush and rag with it on the ways and it didn't seem to worry the paint. Didn't get into the tiny pitting though, which is hardly surprising. It's advertised as getting rust stains off of cement, which it does, and for cleaning silver easily, which it also does.

Might get your stains out of the ways - worth a try.

Considered trying some hydrochloric acid, but didn't.

Then I hooked up the battery charger and got some washing soda going in a plastic bucket on a small rusty and partly painted bit.

At 12 v it's drawing 1.5 amp and gassing nicely. Scum rising to the top. But I think it's taking the paint off as well.

Will check it tomorrow.

Certainly doing something quite well


Rob

Thanks Oldneweng for the tip re Tarn off. Just rang my local Mitre 10 store. "Yep, we stock it, it's $25 for a 250ml bottle".

Bruddy ell, back in the 80's it was $6.99 according to Rosemary Margan.

Rosemary Margan - Classic "Tarn Off" Silver Polish Ad, 1984 - YouTube

Anyone know what's in it that makes it so expensive?

Ken

Originally Posted by nearnexus

At 12 v it's drawing 1.5 amp and gassing nicely. Scum rising to the top. But I think it's taking the paint off as well.

Rob

I think you will find any electrolyte will take the paint off. Some just do it faster then others.

I have recently found a product at Bunnys, it's in the paint section with
All the rust treatment products. I can't for the life of me think of the
Name, but it is a clear liquid and comes in 3 or 4 different size bottles.
This stuff is AWSOME !!!!!!!! You can use it straight or dilute it.
All you do is pour the appropriate amount into a plastic container and pop in your rusty part. Almost instantly you will see bubbles forming and hear them, kind of like soft drink fizzing. Depending on the severity of the rust, eg. Light surface rust remove after 10 or 15 min wash in warm water and the rust is complearly gone. Just oil to prevent re infection.

Originally Posted by Ueee

I think you will find any electrolyte will take the paint off. Some just do it faster then others.

Hi Ewan,

Yep, definitely taking off the paint as well.

That's a good thing as I'm going to completely strip this lathe.

Pulled the tailstock apart this arvo.

Cheers

Rob

Matthew_g, that's not good enough. You can't report a product and not know what it's called.

No one in Bunnies will have a clue if asked.

It's back to Bunnies for you to stroll up and down the isles looking for said product. Good excuse for the missus if she asks, "Just doing some research for the Forum dear".

Ken

HI

Swimming pool shops sell citric acid , the stuff found in lemons etc.

Quote from WIKI :

A solution with a 6% concentration of citric acid will remove hard water stains from glass without scrubbing. In industry, it is used to dissolve rust from steel.



And, dairy farmers use Citric acid wash to clean out the stainless steel pipes .

Originally Posted by matthew_g

I have recently found a product at Bunnys, it's in the paint section with
All the rust treatment products. I can't for the life of me think of the
Name, but it is a clear liquid and comes in 3 or 4 different size bottles.
This stuff is AWSOME !!!!!!!! You can use it straight or dilute it.
All you do is pour the appropriate amount into a plastic container and pop in your rusty part. Almost instantly you will see bubbles forming and hear them, kind of like soft drink fizzing. Depending on the severity of the rust, eg. Light surface rust remove after 10 or 15 min wash in warm water and the rust is complearly gone. Just oil to prevent re infection.

Could it be
CLR ?
Grahame

Phosphoric acid would be my bet. It's about half the price if you buy it from over in the 'real' builders supplies aisle, where it's sold for tile or concrete cleaning.

And you can buy citric acid from near where the driveway/garage floor paints are sold, as it is used to etch concrete prior to painting.

As long as you don't mind the fume, hydrochloric acid is a realllly good derusting agent. Just don't store the container near steel.

Originally Posted by morrisman

HI

Swimming pool shops sell citric acid , the stuff found in lemons etc.

Quote from WIKI :

A solution with a 6% concentration of citric acid will remove hard water stains from glass without scrubbing. In industry, it is used to dissolve rust from steel.



And, dairy farmers use Citric acid wash to clean out the stainless steel pipes .

I don't know anything about the dairy industry but in wineries citric acid is used to neutralize equipment such as stainless pipes after being cleaned with caustic.

I have all the acids mentioned here but I am not sure about using acid on precision ground surfaces. I wouold want to be completely sure it was the right thing to do before I did.

Dean

I cant imagine that in the short term citric acid is going to do much harm.....but I'm not sure I want to rinse my lathe in water... so how else would you remove it?(or is it so weak as to not be an issue?)

Isn't Phosphoric acid rust "converter" not "rust remover?
wiki agrees with me "Phosphoric acid may be used as a "rust converter", by direct application to rusted iron, steel tools, or surfaces. The phosphoric acid converts reddish-brown iron(III) oxide, Fe₂O₃ (rust) to black ferric phosphate, FePO₄."

Stuart

The washing soda works well to loosen the deep ingrained rust, but you still need to use a wire buff after you rinse off the bit, to remove the thin coating of dark stuff that sits there.

It comes off dead easy with the wheel. I also use a small wire wheel in my air die grinder to get right into the corners and tight spots. Fantastic tool.

Then I tossed the cleaned bits into a tin of diesel - to keep em shiny until I need them.

Have pulled the tailstock totally apart and the wear is not enough to be a problem. But there is wear, as you would expect. The bed looks 100%.

Rob