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Hi,
Ive got a block and head casting that need a proper clean. Theyve been sat in a damp shed for years and have a fair build up of rust. Its not so much the accessable surfaces but the oil and water ways. Has anyone used any homebrewed solutions or companies that they can recommend?? Many Thanks

That "varnish" you get build up on everything is removed best by cellulose thinners.

For horrible crud, I'd use a strong solution of phosphoric acid.

I went to my chrome and zinc platers. They plunged a very grotty cast iron S block and fifty quid later out came a brand new one. Truly astonished inside and out no rust anywhere and nice shiny cast iron everywhere. Beats fannying around with wire wheels and scrapers just to make the outside look presentable IMO. Top top though, remove everything. I left my cam bearings in situ and it dissolved them good luck. Mark

I've had some success soaking rusty parts in white vinegar from the supermarket. It's very cheap ($1 for 2L) and it's also not dangerous to get on your skin or put down the sink.

Buy this.

http://www.kustomrama.com/index.php?title=StripAll

I cannot rate it high enough. It works as well as it says, maybe even better. Not very harmful.

FANTASTIC stuff.

A good mate of mine has done many castings by electrolysis method and it really surprised me just how well that works, I'd suggest googling it. I think it's pretty easy and cheap to do.

I use phosporic acid and works very well on rust, but can get expensive.

Rust removal works in a couple of ways and there is various chemical pathways appropriate to a variety of uses.

Here they are in order of increasing mentalness.

1. Oxalic Acid Solution. In this, oxaclic acid, which is like a double ended molecule of vinegar reacts with the rust forming water soluble iron oxalate. You need a strong solution of this and it needs to be hot to work well. The bonus is it will not f*&^ up your castings or leave stains.

2. Phosphoric Acid. Same as above, found in commercial rust remover....Converts rust to iron phosphate....this is a bit more gnarly to get rid of, but you scrub it off. This will play hell with more reactive metals. This is what I'd use.

3. Conc Sulphuric. This is what you use to burn holes in everything, including yourself. It strips everything, including fat, grease, rust and the surface of the iron itself. It is cheap and works.


The stuff Vegard is talking about is a mixture of a chelating agent (like a grabbing molecule) and enough hydroxide to make the pH right for it to work. To make this, you need to get EDTA. NOT THE SODIUM SALT. Ethylene-diamine-tetraacetic-acid....it's like oxalic acid, but moreso. I believe the standard recipe is to get EDTA and make up about a 5% (by volume) solution and then whack it up to about pH9 using caustic soda, or any other alkali you can get your hands on. This is a truly awesome recipe which works a treat. You should be able to get EDTA (not Na Salt) on ebay and NaOH from down at your hardware store

Thanks for all the replies, much appreciatted.

Vegard wrote:Buy this.

http://www.kustomrama.com/index.php?title=StripAll

I cannot rate it high enough. It works as well as it says, maybe even better. Not very harmful.

FANTASTIC stuff.

Veg, that looks like just the job!
Plenty of references like... ..."toxic waste"..........."extremely hazardous"........danger of death........etc, etc.....
How long before someone bans it in favour of an alternative that doesn't actually work!

Molasses . Ratio 4 water 1molasses
No nasties
Goff

In the shed wrote: The stuff Vegard is talking about is a mixture of a chelating agent (like a grabbing molecule) and enough hydroxide to make the pH right for it to work. To make this, you need to get EDTA. NOT THE SODIUM SALT. Ethylene-diamine-tetraacetic-acid....it's like oxalic acid, but moreso. I believe the standard recipe is to get EDTA and make up about a 5% (by volume) solution and then whack it up to about pH9 using caustic soda, or any other alkali you can get your hands on. This is a truly awesome recipe which works a treat. You should be able to get EDTA (not Na Salt) on ebay and NaOH from down at your hardware store

Agree with all you have said, would add that Citric has acidic and chelating properties also.

If you take 5% EDTA in acid form and add sodium Hydroxide won't you simply create the Sodium salt by neutralising the acid ? (4Na?)

Chelating agents still work well in Alkaline solutions too, I think you'll find Vegard's one is caustic (alkaline based).

I use phosphoric / Citric with a glycol ether solvent as a diluent, this dries quicker than water based solutions and does not introduce water to bare steel !

Gotta love da Chemistry!

I use citric acid (bought on ebay for making 'bath bombs') in water. Dead easy, cheap and very safe. It usually takes about 24 hours in the concentration that I usually use, however I recently did the inside of my petrol tank, so I mixed up everything I had in about 30 litres of water and used that. It took about 4 days.

Afterwards I wash off in hot water with a mildly caustic non-solvent degreaser which helps remove the grey residue that is left on the surface and neutralises any remaining acid. After that stuff stays bright for several days with no other treatment.

Tim

Vegard, that strip all looks pretty impressive, however they only sell it in Scandinavia.

I have always been a great believer in Hydrochloric acid, sold as brick cleaner. Followed by a neutralising dip of fairly dilute Caustic soda.

I have also used electrolysis, but this takes for ever.

That stuff sold in Norway looks awesome. I wonder if the powder could be exported via normal postal service. My suspicion is that it can't.

That is a very good point and one which I didn't think about. It would indeed form the sodium salt, which would block up the molecule!

masnarda wrote:Vegard, that strip all looks pretty impressive, however they only sell it in Scandinavia.

I'll check it out. Maybe it could be sent as cocaine or something to get through customs...

What an excellent idea!

You do appreciate the fact that the MK1 forum is now on a CIA database thanks to the above comment

I've talked to my supplier. He can send to England if you'd like.

Could be sent in 10kg containers. Cost is £80 + P&P. which would be around the £40 mark.

Worth EVERY penny!! Seriously.

Contact me if of interest.

Vegard,

How much stripping would 10kg do?

mk1 wrote:Vegard,

How much stripping would 10kg do?

50 liters of fluid. The fluid could be used MANY times. I have used 20 kg in 100 litres for two years. I guess I've stripped 20 blocks.