Alloy engine casting protective

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I have painstakingly cleaned (Dishwashers are great !! ) and glass bead
blasted an old Lambretta engine casting. Part of a restoration project to re
live my youth.
Looks better than new now ( if that is possible? ) and was wondering if any
of you kind folks have any suggestions as to how to keep it looking this
way. My natural instinct is to spray it in clear lacquer........ but I'm no
finishing expert.
All I want is that the casing does not start to dull and then oxidise back
with the white stuff that likes to grow on alloy.
Grateful to any advice received.
Bob
Reply to
Nospam
project to re
oxidise back
It'll all be dirty again by the time you have blasted down to Brighton and had 'meaningful discussions' with the Rocker opposition from the safety of your massed group of Mods !!!!!!
AWEM
Reply to
Andrew Mawson
Well the bikes of the era were no problem as the aluminium castings were not a hotch potch of metals and so a bit of Solvol Autosol and they come up like new.
I suspect the scooters had die cast bits and bobs, just like the Japanese stuff, made with a wicked mixture of metals you don't want to let see water, so I presume they were lacquered. Thats why you so often see the maggotty corrosion on old japanese engines where it has got through the coating and burrows its way under (oh dear, what a shame). I am not sure you can anodise such a mixture, but will be interested to hear otherwise.
Lets face it scooters were just a fashion accessory, designed to be thrown away - but I suppose it is worth keeping a few, just to give us bikers a laugh !
You might find advice from japanese bike restorers, I should think they have similar problems. Its not really a Model Engineering topic, try another newsgroup.
Steve
Reply to
Steve Richardson
Thanks. Your right, this is the wrong group for that question. I watch the articles on this group as I am actually involved in engineering on a commercial and hobby basis. I operate CNC and older emimec auto lathes. One day someone will want a Tom senior, or a vertical quill feed head for either the Tom or the Centec..................... Bob
Reply to
Nospam
Co snipped-for-privacy@gmail.com wrote:
My wife bought a cast iron statue of a chicken that was fairly rusty. I wire brushed it, but my wife did not want it painted. So I sprayed it with some stuff called Product 1900 Clear Corrosion Compound sold by CARE Laboratories in Collegeville PA. It dries slowly and is suppose to be able to be sprayed on surfaces that have salt water on them and it is suppose to displace the salt water. Developed for airplanes on aircraft carriers. Meets Mil-C-85054 ( AS ) Type 1.
I forget when I did that, but no rust so far.
Dan
The author of the reply was d cast snipped-for-privacy@krl.org, no idea whether that is the real email address, or not. He must have great spam filters if it is. Take out the spaces in the address, I put them in.
FWIW, anyway.
Regards,
Adam Smith, Midland, ON Canada
Reply to
Adam Smith
bead blasted an old Lambretta engine casting. Part of a restoration project to re live my youth.
if any of you kind folks have any suggestions as to how to keep it looking this way. My natural instinct is to spray it in clear lacquer........ but I'm no finishing expert.
back with the white stuff that likes to grow on alloy.
I have never found a solution other than not to take the bikes out! Are lambretta castings rough sandcast or smooth diecastings. Sandcast stuff is just a nightmare to keep fresh.
My Moto Morini crankcases would go off in about a week if they got wet! I cleaned mine initially with Phosphoric acid based cleaners. But there's only so much of that stuff the casting will take !
The only solutions are far as I know and they only upset the purists ;-) are Painting (a lot of jap bikes cases were painted) or some form of anodizing. But not all alloys are suitable, and if there are any ferrous inserts in the castings anodizing is out of the question.
Another method would be just to make them dirty with waxoil or something similar, at least it will wash off with a lot of work, but of course will attract all the crud.
Sorry to not have a solution.
BTW They're not "tossers" you just happened to walk straight into the usual banter in here ;-) At least your names not gareth ;-)
Wayne....
Reply to
Wayne Weedon
Lets put a few things right for you first.
These scooter enthusiasts today ..are not mods ........I've seen then at car shows etc ..they are more like the bikers of old .
EG Greasy not afraid to get there hands dirty and dedicated to their machines. :)
a scooter was probably better built and more durable than many Brit bikes of the time .. me... bikes used to run in my blood ...im not biased.
the casings
you got a number of choices .
laquire.............will begin to flake and corrosion will actually spread under the stuff.
my choice .............etch primer .........followed by "alloy wheel paint"...........will look great and last.
BTW ........... if you never take it out when salt is on the road ....your bare bones bead blasted finish will hold up for years ....and may just require the occasional wipe over with oily rag.
all the best...mark
Reply to
mark
engineering
Bob,
It is quite a friendly free-for-all here, so I am not complaining about your question, just pointing out that you may get better advice on a newsgroup that handles japanese bikes. As I have ridden the same Norton for 30 years, you can hardly image I wouldn't have a polite dig !
I am not sure about anodising die cast alloys - no one has jumped in on this yet, and if it is possible it may be the best protection, however I have a sneaky suspicion that it may not work due to the strange mixture of metals (Al, Cu, Mg. Zn, Fe, ...), normal sand castings are (I think) aluiminum with some silicon to improve the flow, and rarely such a complex mix. These seem to come up like chrome when polished, and stay bright and shiny a lot longer afterwards, but any decay due to muck and rubbish is alway very superficial and polishes off.
The die cast alloys need more protection, the metals in them are different places in the galvanic series, so they form their own little mini batteries, which is why you see this maggoty corrosion underneath a lacquer layer. While the lacquer stops the water getting in it is great, but when it is behind the lacquer, then it makes things worse (as does engine heat).
Steve
Reply to
Steve Richardson

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