Alloy deep clean

Paul Marx

Paul Marx

Hero member
Location
France
I'm looking into means of cleaning up crankcases, head and cylinder block on my burnt 3C. The parts are full of burnt oil. The crankcase will come out clean, I don't know about the other bits but I can only try.
There is vapour blasting with of course the need to keep the blast medium out of screw holes and oilways, and nooks and crannies. The process is available locally.
Also available locally is cryo blasting using carbonic ice and high pressure water cleaning. There's a company locally using the process, they work on parts for the aero industry. I'll phone them to enquire if the process is suitable for our soft alloy castings.

Any thoughts on the performance, advantages and disadvantages of the various options?

Paul
 
Paul Marx said:
Also available locally is cryo blasting using carbonic ice and high pressure water cleaning. There's a company locally using the process, they work on parts for the aero industry. I'll phone them to enquire if the process is suitable for our soft alloy castings.
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I met such a specialist when I was helping a friend after the flood disaster on the Ahr. At that time he successfully cleaned a lot of innards from complex machines with carbon dry ice.

The blasting material turns into gas and water and therefore has no harmful residues itself. What I can't tell is whether the blasted debris itself (such as the carbonized oil and other dirt) could become lodged in oil wells and cause downstream problems later.
 
Not sure if it works on burned oil, but maybe worth a try...? I have good success to remove any oil-based dirt on my bike with - WD40! Believe it or not, even tar or chain-lube comes off very easily.

You could first try it on the under-side of the engine case with a brush and let it work there for a while... Good luck!

EDIT: Diesel worked VERY well, too, on a 2 Stroke engine with lots of burned oil in the exhaust. Just let it sit some time (like a day or two)in the Diesel and see if that helps getting it off the aloy.
 
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Being burned on is a problem, I’d be worried it may be more than skin deep.
I know caustic oven cleaner is bad on AL but might be worth a trial. Based on only limited experience (the trays in my kitchen oven) you only leave it on long enough to soften the tar then scrub it off without delay and rinse with plenty of water, then treat with a little oil.

And be prepared to paint the whole engine black 🤔
 
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There are cleaning solutions which will remove carbon from pistons as an example. If i was in your place, I'd look in the yellow pages or the equivalent for suppliers of cleaning materials. Ask them what engine reconditioners or similar are using as a wash/soak liquid.

Did just that locally some years back and have been pleasantly surprised at how aggressive some of these solutions are.
Wear protective equipment - not latex gloves as some of this stuff goes straight through them.
 
Sir Sidney Ruffdiamond said:
I thought vapour blasting had no media ?
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Hi,
Vapour blasting or aqua blasting all use very small media (beads).
To descibe vapour blasting : Imagine a single glass bead fully encased in water. The bead is shot out at a high speed and once the water/bead contacts the component it immediately turns to steam (vapour) which tends to implode on the aluminium surface which removes crud etc. therefore creates a polishing action as the bead is 'bounced' off the aluminium, not like dry blasting which is abrasive (no cushioning).
Vapour blasting is very similar to boat propeller cavitation but leaves the propeller tips nice and shiny, however, metal erosion is a by product.
 
I use vapour blasting a lot, and I have a set of plugs to screw into every orifice including 9mm threads brazed to 10mm nuts, when I get the items back I make sure they are dry and then blow everything with 100PSI air, and work a tap into every single female thread with air as well, then when done into the dishwasher, and after more plain water under prssure (salt in dishwasher), finally good old soap and water and more rinsing, you do need an unimportant space with rough surface to do this, fortuantely my drive is only a rolled stone road, so this works well, with everything up on an aluminium perforated step.
the aerospace variety seemslike a good option to me, plenty of 50 and 60 year old light aircraft continually being rebuilt and maintaned to the required high standards near me (Biggin Hill) age does not seem to worry them, my favourite L/A is G-BSVM a four seat Piper PA28 Warrior, that I have flown a good few times over the last 20 years, it was 30+ years old the first time I was in it. Still looks very good to this day.
CLEM
 
Vapour blasting is what all the full rebuilds on Laverda engine's get here. At Italbrit. Just make sure you blank off any blind holes and thouraly clean out an media afterwards then blow out with compressed air.
 
I have used vapor blasting on several rebuilds on all aluminum parts. It is great for carb bodies. I wouldn’t blast anything that is assembled since it wouldn’t be possible to flush out media with hot soapy water. I would worry also that vapor blasting would alter the look of the rough cast Laverda cases.
 
I would dry blast crankcases as wet blasting will give a semi gloss finish. You can always blow out drillings later or even high pressure wash them to be sure I dont know about lavs but Ducati cases look awful if you wet blast them..
 
Scout63 said:
I have used vapor blasting on several rebuilds on all aluminum parts. It is great for carb bodies. I wouldn’t blast anything that is assembled since it wouldn’t be possible to flush out media with hot soapy water. I would worry also that vapor blasting would alter the look of the rough cast Laverda cases.
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It was vapour blasted first time around when I entrusted Keith Nairn with the engine. It looked great.
Paul
 
Surprised noone has mentioned soda blasting. My home setup is too low powered and slow for any large areas but great for cleaning small components, especially anodised stuff and plastics. Don't know how much more aggressive proper commercial setups are, but zero risk from any residual particles?
 
Thanks to all. Crankcases would come out ok with elbow grease. They clean up with brake cleaner and a brush.
Will phone around to see what the various local companies have to say about it.
Paul
 
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