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Rust in collet system

My old faithful Black and Decker valve refacer has given perfect service for

15 years or so. It's spent most of that time in the garage subject to whatever vagaries of temperature and moisture exist in there and the last few years in the kitchen (don't ask). All was well until last year when the central heating boiler broke and I had to boil kettles for a bath every day. A few weeks after starting this I used the machine for the first time and the collet system was rusted solid. It's a double ended push collet with an internal 45 degree angle to the bore it sits in and another tube with same angle which screws against the back end of the collet to compress it. This tube is a very close sliding fit in the bore, both are hardened and ground and they'd rusted together. I cleaned the bore out with steel wool, same with the o/d of the tube but a few weeks later it was rusted tight again.

Hardened steel is reasonably rust proof but once it sets in you're buggered basically and it just comes back at the slightest opportunity. I can't use oil because the fit is so tight the oil film is enough to jam things up. WD40 would probably be better and I must go and get some. I'm just wondering if there's any way I can stabilise the rust that's already eaten through the hardening and is growing again out of the soft steel underneath. Naval jelly? If I don't fix it I'm going to end up with a scrap machine that is perfect in every other way and that will piss me off mightily.

So far it hasn't affected the operation because the rust patches only form part of the bearing surface so no actual play has developed. However if I keep using abrasive inside the bore and on the o/d of the tube I'll eventually end up with a sloppy fit between the two and then it's all but over.

Reply to
Dave Baker
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Did you take the coal out first ?

-- Regards,

John Stevenson Nottingham, England.

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Reply to
John Stevenson

Dave Baker wrote: I'm just wondering

Google "Electrolytic rust removal"

You'll need a battery charger and a bucket of water with some Daz in it.

Converts all the rust back to steel.

Reply to
bigegg

Very interesting, cheers.

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This would appear to be exactly what I'm after. I've got a workshop full of tools, milling cutters and other things that could benefit from this. Ummm, anyone know where I might get an industrial size battery charger and a plastic tank big enough to drop a Colchester Student into :)

Reply to
Dave Baker

I believe it will also work by holding the electrolyte in a wet sponge, so you don't necessarily have to immerse the object (yes, I did see the smiley but it's still a useful option !).

-adrian

Reply to
Adrian Godwin

Dave, Once you have done your de-rusting (and yes it does work!) consider storing those things that you can't lubricate in a cupboard that is gently heated. I use two standard, similarly rated, light bulbs connected in series across the mains this gives a total heat of about half the rated power of one bulb and ensures long life. two 60w bulbs giving 30watts total heats about 5cuft in my garage. Mount the bulbs at the bottom of the cupboard and arrange some wire mesh to protect them. The spiders love their new home and my precious tools stay rust free. hth

Bob

Reply to
Bob Minchin

In message , Bob Minchin writes

And while you are at it, drape a couple of good old blankets, candlewick bedspread or similar over that rusting lathe and put another low power bulb under that.

Better still, especially from the point of view of your electric light bill, take a look at the low luminosity high infra-red bulbs used for brooding day-old chicks (if such things are still available in this day and age).

Reply to
Mike H

I'm not sure about that.

I thought it worked by producing hydrogen at the surface of the metal which removes the rust.

There is also apparently a danger (theoretical?) of hydrogen embrittlement.

Russell

Reply to
Russell

Leaves a not-so-nice surface. I wouldn't use it on precision parts.

I would use a very fine 3M pad (1200 grit) and polish the rust off.

Nick

Reply to
Nick Mueller

Not exactly.

I don't know about the hydrogen embrittlement (I think that's caused by welding).

It works by electrolytically breaking down the FE02 to FE + 02

(ie, forces the rust back to iron and oxygen)

It won't work on flakey rust (you end up with flakes of iron) and won't fill holes.

Reply to
bigegg

I've tried this and it works very well at removing rust - but I hunted around for some more info as it's clearly more complicated than conversion of iron ions to iron as you see gas at both electrodes.

At the cathode positive ions will be reduced provided that they are in electrical contact with the electrode.

Hydrogen is definitely produced - you can see the bubbles and it is possible that ferrous ions at the boundary between the rust and the parent metal will be reduced to iron. It is the production of the hydrogen which leads to the possibility of hydrogen embrittlement but I have no idea whether this is more than a theoretical risk and I can't find any good info either.

There's an interesting link here which goes into more detail.

Russell

Reply to
Russell

but he forgot to include the link.

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Russell

Reply to
Russell

this. Ummm,

Well I did make a long thin tank out of 110 mm soil pipe to de-rust a Colchester Student lead screw a few years back and it came out an absolute dream - the oxygen gets sucked out of the rust and the 'steel' that is left falls away as a very fine powder that can be washed off.

AWEM

Reply to
Andrew Mawson

Just make sure the Anode and Cathode are the right way round once gave an item to out trainee to de rust and ended up with a badly pitted handle it only had light surface rust to start with

Andrew

Reply to
Andrew Bishop

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