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Corro Dip - If you were wondering.....

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jimi43

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Over on the HAND TOOLS forum, those interested will have watched the slow restoration of the German Horned Smoother.......yesterday's only bootfair find.

I thought it would be interesting for those readers of the GENERAL FORUM to post the result of a night in warm CORRO DIP...my favourite rust removal chemical.



Quite impressive eh!?

It's not cheap stuff but as can be seen....quite effective!

The key to this stuff is that unlike any other process...the crispness of the mark is retained. All too often you get softened or obliterated marks as a result of over-zealous rubbing on wire brushes, abrasive papers and polishers.

For the historical restoration of old and valuable tools...this has to be one of the best methods which retains the maximum amount of the unaffected metal.

Jim
 

wallace

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Blimey its expensive, over £100 for 5 ltr. How many times can you use the solution, does it depend on how rusty an item is.
Mark
 

jimi43

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wallace":1udeiixe said:
Blimey its expensive, over £100 for 5 ltr. How many times can you use the solution, does it depend on how rusty an item is.
Mark
Hi Mark

That is concentrated.

You only need 1 litre...which dilutes 5:1 to give 6 litres for about £20

It is totally reusable....so I just filter off the rubbish at the bottom each time and put it back in the tub,

It doesn't appear to have lost its effectiveness....and I still have about 1/2 ltr of concentrate left.

It is also totally user friendly...I just dip my hands in it to remove the bits. Much nicer than using concentrated phosphoric acid...more effective by far...and less dangerous.

Jim
 

Eric The Viking

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That is impressive!

And timely too as I have some work to do of that sort, soon. I'm going to try electrolysis too (just rebuilt a battery charger for the porpoise), but Corro dip is on the list for the tricky bits.

Thanks for posting Jimi.

E.
 

9fingers

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Never tried corro dip but I can thoroughly recommend the electrolytic method Eric, but keep the current down for best results to minimise gassing as the bubbles interfere with the process. Less than an amp unless the object is huge.

Bob
 

DrPhill

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9fingers":3g1iqa24 said:
Less than an amp unless the object is huge.
It is quite large - it is a porpoise!

Eric The Viking":3g1iqa24 said:
(just rebuilt a battery charger for the porpoise)
(Sorry Eric :D )

Looks like excellent stuff though. Very impressive.
 

Eric The Viking

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DrPhill":r1uv1jt9 said:
9fingers":r1uv1jt9 said:
Less than an amp unless the object is huge.
It is quite large - it is a porpoise!

Eric The Viking":r1uv1jt9 said:
(just rebuilt a battery charger for the porpoise)
(Sorry Eric :D )
It's fine.

You weren't to know I'm restoring a Cetaceanary engine. :)

I'll get me trunks an' flippers...
 

Steve Maskery

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I'm not sure that would make much difference. The electrolyte only allows the current to flow, I think it can be just about anything. My chemistry is a tad dated, though, so I may be missing something. But I think that as long as it is more electro-positive, the oxide will move from the cathode to the anode. Or is it the other way round? Nurse! NURSE!
S
 

thick_mike

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A couple of notes on electrolytic rust removal from my experiments:

You just need to put a salt of some sort into solution to allow the current to flow. Bicarb or washing soda will work. Table salt (NaCl) is less preferable as chlorine gas (toxic) can be discharged at the anode.

You're basically electrolysing water so you get hydrogen gas given off at the cathode and oxygen gas given off at the anode (you can check this by holding a match to the bubbles formed, they do the squeaky pop you might remember from chemistry in school). The electrolysis doesn't plate iron onto the surface of the part you are de-rusting (the cathode).

The hydrogen seems to reduce the iron from Fe2O3 to Fe3O4. The Fe3O4 is sometimes called black iron oxide, which is not crumbly like normal rust. So the surface is cleaned and more robust, but it isn't shiny metal.

That is my experience and of course your mileage may vary.

I'd love to know what the active ingredient is in the corro-dip. It would defy the laws of chemistry if it carried on working for ever, so it must lose effectiveness eventually. It certainly brings the shiny though!
 

DTR

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I'm about to take the plunge (not literally) on this corro dip stuff. My only concern is that it will ruin the logo etch on a saw plate. Fair enough if there is rust beneath the etch, but what if there's not?...
 

jimi43

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DTR":3bah36ww said:
I'm about to take the plunge (not literally) on this corro dip stuff. My only concern is that it will ruin the logo etch on a saw plate. Fair enough if there is rust beneath the etch, but what if there's not?...
My personal view is that it will possibly destroy the colouring of any etch but not necessarily the depression which can be recoloured afterwards.

If I were thinking about doing a saw of potential value...monetary or sentimental...then I would try it on an old S&J first or knackered Disston...

This applies to any unknown..including finishes, polishes etc.

Jim
 

marcros

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has anybody found a source other than the manufacturer direct?
 
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