Got some old rusted machinery - AND IT WORKS NOW!

[elShoggotho]

To be exact, it's a small screw press. The whole thing is so rusted that it can't be moved at all. Soaking the screw in WD-40 right now, but I need some more hints.

EDIT: Thank you, everyone! Your hints, and some SCIENCE, have done it.

[Mr. Boltneck]

There are a number of people who swear by http://www.instructables.com/id/Electrolytic-Rust-Removal-aka-Magic/. I have no idea if this can work on an assembled device, though. There are also a number of chemical rust removal chemicals available (http://www.eastwood.com/rust-solutions.html for an example), some of which may not actually try to dissolve you.

[Wormster]

Bung the whole lot in a vat of diesel for a week or 2, that'll penetrate far better than WD40.

[elShoggotho]

Addendum: After a night in WD-40, I could loosen all the secondary screws. Removed what I could, including  the upper tool. Loosened the lower tool. I suspect that there's a thoroughly rusted spring down in the housing. Cleaned the outside with a wire brush, found some brass parts. Main body is cast iron, with machine forged tools. If I could, I'd sandblast the whole thing.

[Maets]

Sand blasting takes away too much.  Better to leave some age.  A wire cup brush on an angle grinder works wonders for places it can reach.  Chemically there is some stuff called Blaster that is by far the best stuff for loosening up parts that seem to be rusted into one.  www.BlasterProducts.com

[dingbat]

To be exact, it's a small screw press. The whole thing is so rusted that it can't be moved at all.

WD40 isn't much use - a real penetrating oil is better. Can you find Plus-Gas or similar?

The real solution though, especially as it's cast iron rather than steel, is to use electrolytic derusting. Web searching for this, especially under woodworking tools, should turn up something. You need a plastic bucket, a car battery charger, a piece of scrap steel (stainless is good, kitchen scrap is ideal) and a handful of washing soda. It's a simple and cheap technique, albeit a bit messy, and quite amazingly effective.

NB - Negative lead (black) to the thing you want to keep! The thing attached to the positive lead (red) will disappear!

A good setup will run at about 1A current for a woodworking hand tool, more for bigger pieces (I've used 150A for a canal boat). Expect it to take a day or two. The process is self-limiting, so even a week is no problem.

NB2 - Mains power switched OFF before you go near the wet part. If this is correctly earthed in the UK, you're unlikely to injure yourself. However a belt at this current is very painful.

[jringling]

Believe it or not... soak it for 2 days in clean water... take it out and wiggle everything. If it isn't loose, back into water for 2 days... take it out and wiggle everything. If it isn't loose, back into the water for 2 days... and so on...

Water got it stuck, so water will un-stuck it...

[elShoggotho]

A morsel of information: The inscription reads DAUDE No. 6 PARIS.

To be exact, it's a small screw press. The whole thing is so rusted that it can't be moved at all.

WD40 isn't much use - a real penetrating oil is better. Can you find Plus-Gas or similar?

The real solution though, especially as it's cast iron rather than steel, is to use electrolytic derusting. Web searching for this, especially under woodworking tools, should turn up something. You need a plastic bucket, a car battery charger, a piece of scrap steel (stainless is good, kitchen scrap is ideal) and a handful of washing soda. It's a simple and cheap technique, albeit a bit messy, and quite amazingly effective.

NB - Negative lead (black) to the thing you want to keep! The thing attached to the positive lead (red) will disappear!

A good setup will run at about 1A current for a woodworking hand tool, more for bigger pieces (I've used 150A for a canal boat). Expect it to take a day or two. The process is self-limiting, so even a week is no problem.

NB2 - Mains power switched OFF before you go near the wet part. If this is correctly earthed in the UK, you're unlikely to injure yourself. However a belt at this current is very painful.

Would caustic soda do? Strangely, I have more NAOH than washing soda.

[dingbat]

Would caustic soda do? Strangely, I have more NAOH than washing soda.

No. (No!) This would make the mix hazardous to handle, and also corrosive.

You could use almost anything here - you're just adding a source of ions to make the water conductive. However you should add something that won't bring its own problems. Bicarbonate of soda is rather ineffectual, common salt and especially caustic soda will cause future corrosion problems. Washing soda is benign, cheap, and also acts to emulsify oil and grease. If your iron is oily as well as rusty, you can sometimes get trouble where the oil layer acts as an insulator - washing soda helps remove this layer.

[Maets]

Vinegar works well. 

[elShoggotho]

IT WORKS!

In the end, the mix of WD-40, vinegar and slight percussive persuasion succeeded in reactivating the screw press. I just hit the arm with my hammer, to test if it budges. It did, so I hit it a bit more, until the screw came loose. Astoundingly, the return spring still works! It makes dents in steel goggle frames without any effort. Now I just need a cutting tool for it.

[architect]

 

[Mr. Phikset]

Is this Daude perchance a riveting machine?

[elShoggotho]

Well yes, it is - and it's manifique.

[Jedediah Solomon]

Actually, WD-40 comes in a liquid to be used in a spray-bottle and it works great for soaking.  The 'aerosol can' product usually dries up before it does anything effective

[Jedediah Solomon]

When restoring old gadgets, it is a bonus when  they work, but sometimes it  is cool just to have a mechanism that  just looks great. I am a licensed mechanic, and as such I have a lot of tools that I don't need to use all thee time but I daren't discard them ( the very next day would be the time I need it, right?)
I found an  ancient toolbox in my grandfather's  garage only to discover that many of the tools were rusted beyond use. I then de-rusted (is that even a  word?) them and welded studs onto the back, painted them and now use them as drawer-pulls on my drawers ..the old micrometer opens the drawer containing measuring devices, the Manifold wrench... wrenches of course and a "flashlight" (actually pipe with couplers made to look like a flashlight) opens the drawer to .. you guessed it.. flashlights ( also batteries and the like.)
all in all, the old stuff adds distinction and a bit of silliness butt also makes finding stuff easier ffor anyone who doesn't know their way around

[celephicus]

...
I am a licensed mechanic
...
I found an  ancient toolbox in my grandfather's  garage only to discover that many of the tools were rusted beyond use. I then de-rusted (is that even a  word?) them and welded studs onto the back, painted them and now use them as drawer-pulls on my drawers ..the old micrometer opens the drawer containing measuring devices, the Manifold wrench... wrenches of course and a "flashlight" (actually pipe with couplers made to look like a flashlight) opens the drawer to .. you guessed it.. flashlights ( also batteries and the like.)
all in all, the old stuff adds distinction and a bit of silliness butt also makes finding stuff easier ffor anyone who doesn't know their way around

I am an unlicensed mechanic, I hope that the union never catches me! De-rusted is a fine word Sir and I use it myself, let no-one tell you otherwise!

Do post some pictures, It sounds brilliant.

Myself I never label anything in the Inventory, as I don't want casual visitors knowing where my treasures are. Other mad scientists are similar, my colleague Prof. M.H had a set of wooden drawers from a gentleman's outfitters I should think, as it was labeled with the names of items of apparel. One of them was labelled "suspenders", which were actually for socks. Anyway, in the drawer marked "socks" was a Victorian era jar of murky objects in oil, which on examination turned out not to be fetta cheese but red phosphorus as a lump started smoking when I took it out of the oil! Moral: do not poke around in other peoples stuff!