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Discussion Starter #1
So yeah, the bloke who is machining my bores up at the moment has told me that I shouldn't paint my aluminium engine parts because it'll come off within a year.

Has anyone had experience of painting a lump? Is there high temp etch primer that can be used? Any good?

How should you prep aluminium? I've only every painted steel bodywork.

Cheers!
 

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Im with the machinist on this one mate. I have seen them polished and powder coated but i think paint ia very bad idea. If you really want to try it, start by having the casses blasted with a soft media like Walnut shells, follow that with an acid etch primer (dont scimp on the primer, quality will count here). Then use your chosen engine specific paint.

If all you are trying to avoid is suface oxidation, a simple trick is to soak the cases in penetrating oil straight after they have been blasted and leave them to dry. I do this with all my alloy parts and never have a problem.

All the best
Rod
 

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Discussion Starter #3
Okay, certainly something to think about!

I want to paint the whole engine black so it's going to look terrible if it ever flakes!
 

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I don't know what they used but the late Thunderbirds sold in the UK (not in the states?) had an all black engine and it seemed to last. And the Tiger Trail

A guy down my pub in the late 70's had a sort of what I'd now call a flat tracker that had all black engine and chrome covers. It looked great - but chrome covers can look really poor after a few years.
 

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Powder coating seems to stick ok. A friend has a bike shop and has done several engines for himself and for customers (mainly Guzzis and Harleys but a few big Jap engines too). He's always done them in silver as far as I know, and it seems to last very well. I presume they are powder coated straight after being blasted, though I've no idea how he prevents any blasting grit getting where it shouldn't.

Having said that, I sprayed my Guzzi top ends with WD40 as soon as they'd been bead blasted (got that tip from someone) and they stayed looking like new, never a hint of white rust.
 

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Discussion Starter #7
Awesome, I have spoken to local powder coating place now and they reckon I can do the entire engine for about £160. Happy days!

I heard from one bloke that powder coating is bad for heat transfer as they are air cooled but I really can't see it making that much difference. I'll just stick a NH oil cooler on to be safe :)

Cheers mate!
 

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Just be careful about that 'grit where you don't want it' matter! In my experience, powder coating / grit blasting firms tend to sound very reassuring about not getting the grit where it shouldn't end up, but when you get the stuff back, you find it's got just about everywhere. I'd suggest either talking to the person who will actually be doing it and sussing whether you can trust him/her, or being very careful to mask everything yourself before they get their hands on it...
 

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Discussion Starter #9
Yeah, everyone I know has said to go to the same place because of how good they are! He does work for a lot of nodding companies and stuff. I'll be sure to check it when it gets back!
 
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