Saving Old Seagulls

The block were still in electrolytic derusting procedure. I had some results. The rust was removed mostly from points that had eye contact with the sacrificial electrode. You can see that in the broken side much rust was removed, but in the side of the exhaust and from the secret chamber is still there. I get bored with the procedure, studied a little chemistry and now I am up to a method similar to this with the zink. I 'll let you know if it was successful. The condition of the block after all this electrolytic derusting.








The red rust appeared in the surface of the block can be removed easily with a rag. It appears as the water evaporate.

I hope to enjoy my posts

A lot of 'stress relief'. Would it be that hard to get new castings made? Better materials? Maybe an amalgam of brass ?

I think that blocks had it mate

Certainly..!

Well I have news.. The effort to swop zinc with aluminium didn't work. So at this time I have the block in a solution of dissolved zinc with really high PH. Waiting to see results. I weight the block (dry) before this. We will see.

This thing has become frustrating.
I bought some bars or pure zinc, caustic soda (NaOH) and made a solution of NaOH, dip the zinc inside and start dissolving. After that I placed in the solution the block. It was supposed that now positive zinc ions would attack the rust. Zinc anions would steal the oxygen from ferric oxide (rust). But I see nothing happening. All that have happened on a stove on nearly 90-100C. I "cured" the block this way several hours. If anyone could help I would highly appreciated. The procedure I follow comes from here http://www.btc-bci.com/~billben/rust.htm

Be careful, if anyone try to attempt it wear protective equipment. Mask, goggles, gloves etc. The solution penetrate my glove and I felt my finger soapy. That's the red alert, I have started getting burnt from caustic soda. I dip my finger immediately in vinegar and wash my hands. This way prevent burning without pain or signs..

I'm fairly sure derusting with zinc requires the zinc to be in fairly good electrical contact with the iron. Try packing zinc granules into the block then immersing in the saturated zinc alkali solution. The linked page probably has excess metallic zinc suspended in solution as fine particles. The author's knowledge of electrochemistry and redox reactions is even more lacking than mine!

Thank you! You may have saved the game!
I drill a bar of zinc and stuff the turnings in the water ways. One bigger piece put it in the exhaust. Seems to be working. There is something floating on the solution. According to the theory it must be iron, former rust. I can't wait to kill the rust!

Righto, I've heard enough yapping. Going to show you guys how it's done

You get rusty bits cleaned up with chemical cleaning

Complex shapes like engine blocks with hidden galleries are not a problem

Does not remove any parent metal, so is safe to use on honed bores, unlike grit-blasting or acid dipping.

This is the 'Before' picture, weighing in at 215 grams



Should have the 'after' picture in a week or so

I'm re-starting my demo using a new sample.

It was something of an oversight on my part that the crud in the prior sample was casting core material, & not rust, so wasn't a good choice for a valid demo

This new sample uses a Century 100 block cut-away to show the hidden exhaust cooling gallery, which is totally blocked. Obviously mechanical cleaning, like scraping or blasting can't clean this gallery

This is the 'Before' picture, weighing in at 1856 grams

The results are in - at last





Notes;
* 122 grams of rust material removed, that's 7% mass loss
* no harm to the bore
* the light surface rust comes from the final water-blasting wash
* the water gallery behind the exhaust port is now open
* the orange rust is completely removed, However, some of the black corrosion remains

What method did you use?

Which bit do you mean re the hidden exhaust gallery? I'm trying to understand the route the cooling water takes around the exhaust area..

Firstly i'm a fan of head removal and a good grind/drill out of the hard corrosion. But it'll be go to apply a treatment after the mechanical cleaning.


At work we have a chemical called Deoxidine. Anyone heard of it?

In the past i have immersed rusty items into the fluid. It fizzes off the corrosion as soon as it hits the liquid, afterwards you are left with bare metal and the deeper corrosion leaves black looking holes. I havent used it for a few years and it'll be worth trying again.

Bloody stinks though.


Deoxidine 186

Deoxidine 186 is a phosphoric/sulphuric acid based metal cleaner and surface de-ruster for ferrous substrates. It can be used in a spray or immersion system to remove rust, light deposits of mill oil and corrosion initiators. It is optimised for steel surfaces, and can be used under specific conditions on aluminium and zinc (both of which will be lightly etched). This product should not be used on magnesium or yellow metals.

Deoxidine can be used to prepare suitable surfaces for the application of a conversion coating, and where production volume is large, a spray application, in place of dipping, is recommended for economy and handling considerations.

Work coated with mill oil would normally require no pre-cleaning, however heavy deposits of grease or drawing compounds should be removed prior to Deoxidine 186 treatment.

As Deoxidine 186 contains phosphoric acid and sulphuric acid the rule of safe handling of hazardous products should be followed – appropriate protective clothing and footwear should be worn, together with chemical goggles/face shield (meeting BS2092). Good ventilation also applies.

Since it is contains phosphoric acid it should be good. It is the correct acid to kill rust. If you have some it would worth the try to see if it will kill also water jacket's deposits. Never use HCl to kill rust. Rust will return stronger. I will also try a rust remover which contains phosphoric acid. I suggest that after use to neutralize the item with ammonia or lye unless the manual says something else.