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Post by Rex NZ on Dec 1, 2012 7:54:06 GMT -12
You can 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
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Post by thetinker on Dec 1, 2012 18:23:07 GMT -12
What chemicals are you using? Electrolysis seems to work well.
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Post by Rex NZ on Dec 2, 2012 7:49:11 GMT -12
I use these guys metalpolishers.co.nz/The chemical tanks are enormous & he can dip an entire car. The chemical process is a bit of a secret. It's very thorough, &, doesn't waste away any parent material. What I've concluded is * it can't be HCL acid, as there's no erosion or emergence of crystal grain * it can't be caustic because that will attack aluminium * it can't be methyl chloride as that doesn't do much to rust * I doubt an electroylzed process, as electrolyzed methods will struggle to deal with a concealed gallery My best guess so far is we are dealing with a fairly proprietary & aggressive chemical mix that doesn't react with any metallics. Having said that I'm not particularly inclined to back engineer the process too much, as Doug the owner does a good job & is making an honest living.
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Post by Rex NZ on Dec 13, 2012 6:53:57 GMT -12
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
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Post by 1650bullet on Dec 14, 2012 20:43:36 GMT -12
Would i be Wright to say that the acid baths thats used by your local engine reconditioners is ok for such things. Engine blocks and alloy pieces. I have seen alloy motor vehicle cyl heads get dipped and steam cleaned, and they look like brand new again. I have been thinking of sending a whole heap of parts to my engine reconditioner to clean and have them stored away properly for future projects.
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Post by Rex NZ on Dec 15, 2012 5:26:01 GMT -12
Bullet
Sounds like your re-conditioner is 'onto it'
I'd be very confident that whatever they're using will be fine
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Post by 1650bullet on Dec 16, 2012 22:44:02 GMT -12
I just herd about this. Dry Ice Blasting. The big advantage is it wont leave any abrasivness like sand or soda blasting. And you also dont have to worry about any grit getting stuck all over the place, You could blast all the alloy back to its original finish and all the ice just drys up leaving everything spotless and ready to assemble youtu.be/ZrHchu1tNycP-s Sorry about it being a 6-50min movie But it was the best one to show what it does to alloy.
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cobbadog
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Post by cobbadog on Jan 11, 2013 12:19:01 GMT -12
We have a few different types of toys we play with, the latest being a 1946 Lister 8hp diesel engine which is radiator cooled not tank. In a operators manual it states that; "If the cooling system becomes clogged with sediment or scale, soften with a weak solution of hydrochloric acid (1 - 20). Leave standing for 8 hours and wash out. Radiatorsare preferably treated with washing soda (caustic), 1.25lbs to 1 gallon of boiling water." I have not done this as yet to clean the cylinder and head but I will. I have also used hydrochloric acid in the aid to cleaning up some alloy parts of the David Brown carby we have. It did a really nice job but wear a face mask as it does give off gases. AS you may know caustic on alloy only makes it go black. Find some old alloy part and try the hydrochloric acid either with a brush or dip it into a small bath.
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Post by Rex NZ on Jan 15, 2013 6:08:34 GMT -12
Yes, Hydrochloric acid is very good at dissolving rust. The down-side is it's also good at dissolving the parent metal too. The old Lister is really tough & will handle this fine, especially given the acid is confined to just the cooling passages.
The Seagull block is a bit tricky. Here we want to immerse the entire block in a cleaning solution, but, not harm the bore finish
I really must chase down our sample & check progress now that the holidays are over.
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cobbadog
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Post by cobbadog on Jan 17, 2013 12:54:35 GMT -12
I look forward to seeing the result and finding out what it is that the engine reco guys use for cleaning. Maybe a slightly 'ETCHED' bore would be a bonus with a new set of rings to bed into it,
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Post by Rex NZ on Mar 15, 2013 12:00:53 GMT -12
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
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cobbadog
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Post by cobbadog on Mar 16, 2013 16:47:13 GMT -12
Now that is a great result! Have you found out what it is he is using in the tank for cleaning?
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Post by Rex NZ on Mar 17, 2013 6:31:53 GMT -12
Have come up with some possibilities * carbonic acid * lactic acid * Hydrochloric with some sort of inhibitor * other However still not really sure. Need to find a chemist. The fact that it completely removes the orange rust & partially the black might be a clue.
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cobbadog
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Post by cobbadog on Mar 20, 2013 18:51:55 GMT -12
Might be just as easy to ask the guy what it is he uses !!!
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