Anything wrong with painting bare aluminum (engine) parts? Experiences?

Vtx531

Vtx531

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I've been on a spray painting binge today. I had a new belt tensioner shipped to me. It comes in bare aluminum. I don't see any reason why other than cost savings? My old tensioner was pretty corroded (can see it in background of the photo).

I painted the new one and the alternator bracket with self etch primer and hi temp silver paint (that's just what I happened to have on the shelf, not that I needed high temp). Self etch was advice from some bodyshop trade website I came across.

Just wondering if anyone else has done this or any experience? If it is bad then too late now. I probably should have asked first before I did it but oh well.

Bonus was removing the pulley and putting antisieze on it so it might actually come off if I need to remove it in a few years...or come off on it's own unexpectedly one day haha. Definitely going to put antiseize on the mounting surface and pegs too because one of them on the old tensioner got stuck in my bracket and I had drill it out.

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I painted aluminum panels when I worked in a sign shop back in the day. I used an etching primer made for aluminum after that regular paint worked OK. What you did should be OK because heat should not be a problem and I do not think those parts will see any flexing. Pressure washer might take it off though.
 
Hal said:
Acid etch, Aldine, prime, paint.. steps used on almost aircraft aluminum components..
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Will have to look up aldine now because I'm curious. What type of acid? Phosphoric? Is there a special primer and paint for aluminum or is regular old enamel suitable (considering this isn't an airplane)?
 
It will radiate more heat unpainted. It will never really corrode away unpainted. I know you have one that seems bad but it's probably not really anywhere near failure. Do whatever makes you happy, no "correct" answers here.
 
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bucky said:
I painted aluminum panels when I worked in a sign shop back in the day. I used an etching primer made for aluminum after that regular paint worked OK. What you did should be OK because heat should not be a problem and I do not think those parts will see any flexing. Pressure washer might take it off though.
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I suppose if a pressure washer takes it off then I'm no worse off than I started with! This will be an experiment of sorts...
 
Do you need an etch? Maybe. Is it more important to get the parts totally clean? yes.
Only things in the engine bay I'd paint are the block (maybe) with a heat dissipating coat. Or anything steel or iron, for that matter. But all that stuff is meaningless in a non-racecar, IMO. So I paint stuff for rust protection and that's about it.
 
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chimmike said:
Do you need an etch? Maybe. Is it more important to get the parts totally clean? yes.
Only things in the engine bay I'd paint are the block (maybe) with a heat dissipating coat. Or anything steel or iron, for that matter. But all that stuff is meaningless in a non-racecar, IMO. So I paint stuff for rust protection and that's about it.
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Re: parts totally clean. That's why I figured I need to do it now when it is new. Just did a quick wipe with mineral spirits. Not sure if that is good enough.

I lightly sandblasted the old bracket but I didn't do an entirely thorough job so that one might not hold up very well.
 
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jjvw said:
aesthetically corroded or structurally corroded?
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I would say just aesthetically. It did bust apart and leave one of the pegs stuck in the bracket and I blew through the side of it when I was knocking on it with a punch. I think antiseize on the pegs and mounting surfaces would fix that.

Upon further research, it may not be bare aluminum after all. Sounds like the manufacturers might acid dip and do a conversion coating. First two steps in post #2. So it would look nice for a year or two.
 
Vtx531 said:
Will have to look up aldine now because I'm curious. What type of acid? Phosphoric? Is there a special primer and paint for aluminum or is regular old enamel suitable (considering this isn't an airplane)?
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Check with aircraft spruce..they should have supply and details.. ps we even used it on the aluminum engine case.. the acid need to be applied and washed off, as does the Aladin, once dry.. prime and paint with appropriate paint. Once done right it almost lasts a lifetime.. stop by a maintenance shop at a airport.. the love to talk..
 
Apparition said:
Buffer and polish, make it shiny
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man, if this were a show jeep that never got dirty I'd say, sure. But the amount of work to polish, and then maintaining polished aluminum shine, is a pain in the ass. only one on here I see doing polished aluminum/chrome stuff is maybe @mrblaine , he seems like a guy who likes his bling? :ROFLMAO:
 
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chimmike said:
man, if this were a show jeep that never got dirty I'd say, sure. But the amount of work to polish, and then maintaining polished aluminum shine, is a pain in the ass. only one on here I see doing polished aluminum/chrome stuff is maybe @mrblaine , he seems like a guy who likes his bling? :ROFLMAO:
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I hear that, I polished the engine on my Banshee years ago. Still looks good but it's been garage kept and unused.
 
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chimmike said:
man, if this were a show jeep that never got dirty I'd say, sure. But the amount of work to polish, and then maintaining polished aluminum shine, is a pain in the ass. only one on here I see doing polished aluminum/chrome stuff is maybe @mrblaine , he seems like a guy who likes his bling? :ROFLMAO:
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Keeping my alternator bracket bright and shiny sure is a lot of work, but it sure is worth it!
 
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I cleaned up a set of cylinder heads with oven cleaner and a pressure washer. I am trying to remember if I used Rustoleum self etching primer or engine primer, but I used Rustoleum engine paint. Been a year since painted and since April when driving around and has held up great so far.

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