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Discussion Starter · #1 ·
So if I were to cut a piece of aluminum stock (1/8" thick 6061) how would I go about getting it to look like the aluminum bits on the bike already?? Would I need to paint, and clearcoat? Powdercoat? Will bare aluminum rust if exposed to the elements? Metal experts I need your sage like advice here. Keep in mind I am a cheap bastard.

cheers, jason
 

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You'd need to dress (grind, buff, sandpaper, etc.) the finish to look like whatever finish you're trying to copy. Yes, aluminum will oxidize so you'll need to clearcoat the piece(s).
 

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I'm no expert but I have been working with metal all my life and I also am cheap. Aluminium does not rust but it can corrode when it does it gets a chalky look to it. Factory finishes are usually brushed you can achieve this by sanding it smooth and using scotchbrite to get uniform scratches in the surface. This is very time consuming and very tedious work. When you get the desired look you should clear coat it or get clear powder coat or anodising to protect it. You can polish it to a mirror finish by taking emory paper and wet sanding. I usually use 220, 400, 600, 800, 1000, 1500 and 2000 grit papers in that order. Then get some Mother's polish and buff the heck out of it. I would recommend a clear powder coat on that also to keep it nice. It's alot of work either way but if you like doing it yourself it can be rewarding. I can go into more detail if you wish.

[ This message was edited by: meanchuck on 2007-01-09 07:51 ]
 

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You can get clear coat in a rattlecan but I do not know how well it would hold to bare aluminium or if the finish would look good. The clear is not degsined for bare metal and might fisheye real bad. I have a friend that has a powdercoat shop so for me it is cheap to go that route.
 

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Discussion Starter · #6 ·
So I could probaly get away with rattlecan clearcoat after scotchbrite on the surface? I would powdercoat, but I am already looking at about $70 for cutting the piece, and about $25 for the aluminium. I can only imagine having it powdercoated would cost at least $50?

What about taking the bare cut piece of aluminium and rattlecanning it "aluminium" with paint and then clearcoat from a rattlecan. Would that have a similar effect to buffing, and all that?
 

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That would work too and would save you some work, it would look like the silver finish usually on factory cast wheels. I recommend Dupli-color, it's pricey but it's the best rattle can I found. They have have wheel paint that works well on frame parts or whatever you are making and is a little tougher that the standard stuff. I used it to paint a rollbar for my Miata and four years later it still looks great. They also have a graphite gray in the wheel paint that looks really trick. If you use this stuff go exactly by the directions or it will run.
 

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I've done quite a bit of wetsanding and aluminum polishing in my day. I highly recommend not putting any kind of clearcoat or powdercoat over the aluminum. Aluminum oxidation is nothing close to as bad as iron oxidation. As stated before, aluminum just turns kind of chalky but that is over many years and if not taken care of, could pit from salt as well. A big problem with putting a clearcoat over aluminum is it usually will pit/peel. Look at some aluminum rims on some of the cars here in WI, most of them look like ***** due to the clearcoat peeling, which can be started from just a knick. The clearcoat on the valvecovers of my Thrux aren't really peeling but looks like it might start soon right around where the gasket is, I'm assuming that is due to the heat. Keep the aluminum bare, polish it with Mothers metal polish everyonce in awhile to brighten it up, that is all you have to do!


What are you making now by the way? If you wanted the aluminum to exactly match the look of the stock engine covers, headlight brackets, etc... then you'd have to create some minor scratches in the aluminum (using a more coarse sandpaper such as 800 or something) to give it the "brushed" look and then clear coat it.
 

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On 2007-01-09 15:50, OldSkoolFool wrote:
I highly recommend not putting any kind of clearcoat or powdercoat over the aluminum.

........you'd have to create some minor scratches.......... to give it the "brushed" look and then clear coat it.
Huh??? :???: :???:
 

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I have succesfully polished and used turtle wax to preserve the finish on exposed raw aluminum...I have some spikes on my Harley (front axel covers...very exposed) and they look fine...4 years of riding and a quick polish and wax once a year seems to work fine.

Bike has been wet, dry snowed on and baked...no corrosion or lack of luster on these parts...I only wish the steel and chrome would hold up this well.

[ This message was edited by: dcw on 2007-01-09 20:35 ]
 

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Discussion Starter · #12 ·
OldSkoolFool, I have another one of my diabolic projects in the works. (cue the diabolic laughing) and if I am successful, I will pass the info on to my fellow riders!

So if I have bare cut aluminium, I will just have to polish every once in a while to keep its appearance? And to get a similar look to what the bike has (engine covers, triple trees) I just have to sand and then clear? Or just sand. I might be getting confused.
 

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Yes, if you have bare aluminum you'll just have to polish every once in a while to keep it looking it's best.

Motley, brushed aluminum, at least how I interpret it, is not a complete mirror finish as say chrome might be or aluminum that is polished all the way up to say 2000 grit sand paper and then polished with a buffing wheel (which will be very close to mirror finish). I believe Thrux-Ton-Up stripped his covers and polished them to the point of a near finish. Brushed aluminum has more of a texture look to it and you can get that look by not wet sanding/polishing the metal using very fine sandpaper as say 2000 grit. I haven't done it for a little while but a brushed aluminum look could be achieved by wet sanding from say 100 and stopping at 800 grit. The 800 grit will still leave minor scratches in the aluminum giving it that "brushed" look. If you look closely at the side covers on the Thrux engine you'll see what I'm talking about.
Jason, to get an EXACT look to the engine cover, you'll need to get the brushed aluminum look and clear coat it. If I remember correctly the tripple tree aluminum has more of a rough surface, the top if I remember still has the machining marks in it.

Does that clarify anything?

I guess you could look at brushed aluminum being half way to fully polished mirror like aluminum. It's not quite there but close, still has some minor scratches giving it a depth/texture.

[ This message was edited by: OldSkoolFool on 2007-01-09 20:23 ]
 

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Discussion Starter · #14 ·
Thanks guys I think this will help.

Shane, I am gonna take the bare aluminium and sand it to give it some scratches in the surface. And then just rattlecan it with some clear to give it some protection. I think that should do the trick. What grit sandpaper should I use to get that "brushed" look?

cheers, jason
 

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I used to have a cotton polishing wheel on an old dryer motor that I used to polish aluminum. Once you get the clearcoat off, you can use polishing compound, followed by polishing rouge and achieve a chrome-like brightness on bare aluminum. The polishing wheel really eliminates all the elbow grease...it really goes pretty quick. Once it's shined up, you need only dress it up with a chemical polish every so often. It classes up even the most mundane machines...
 

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Jason - check with a few local powder coaters. You may be surprised how inexpensive it is to get it coated in clear. I am having some items done now and small items like shock springs are 5-6 dollars to have coated. It's even cheaper when they do not have to do any metal stripping prior to the work. The powder coat will also last much longer than the factory clear coat that Triumph puts on their parts. You have to shop around though, PC prices run from mild to wild all for the same work. Many modern PC's call for a clear coat for depth and protection they will just throw your part in with the batch getting cleared - no big deal for them.

John
 

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Jason, depending on how rough the aluminum is to start with, just start at say 180 grit and keep wet sanding it using less coarse sandpaper untill you reach the desired brushed look. If you want, email me a pic of what you got. If it's a huge, rough peice of aluminum, your arms gonna fall off from sanding so much :-D

BTW, I'm still waiting to get my parts for the carbs/filters. I'll let ya know when I get em so you can give me a hand. In the meantime I shopped and found a replacement for the stock gauge pods, but it'll need a little modifying. Will look pretty schweeeet though, I'm excited! Gonna work on that this weekend.

[ This message was edited by: OldSkoolFool on 2007-01-10 09:02 ]
 

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Discussion Starter · #18 ·
Thanks again everybody, I will use shanes advice and sand the piece down, and then try and see what my painter will charge for clearcoating some powdercoat on it.

I got some bad news about the project today though, it seems that the waterjet place is gonna have to charge me another $75 for programming the machine to cut it! Thats in addition to the $65 for the cutting. Oh well, I think it will be worth it.

cheers, jason
 

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I have been hybrid polishing Chinese weapons for years. The way we do it to keep control of the evenness of the polishing is to cross hatch each grit while sanding.
In other words, sand at one angle at lets say 800 grit. Then sand at another angle at 1000 grit. Pay attention to when all the grit direction is gone from sanding the other direction. This will tell you when there is un-evenness as well when to change grits.
A good compound to sand with is Windex - Love it. Its clean and has the right amount of moisture before it evaporates. There are other options as well, but this is the cheapest and easiest. Do not use oil or water. Oil builds up unless it is a very light natural oil, such as they use to sharpen knives with and water can get into the metal.

Alrighty - Good luck
 

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On 2007-01-09 20:22, OldSkoolFool wrote:
Motley, brushed aluminum, at least how I interpret it, is not a complete mirror finish as say chrome might be or aluminum that is polished all the way up to say 2000 grit sand paper and then polished with a buffing wheel (which will be very close to mirror finish). I believe Thrux-Ton-Up stripped his covers and polished them to the point of a near finish. Brushed aluminum has more of a texture look to it and you can get that look by not wet sanding/polishing the metal

Does that clarify anything?
OldSkoolFool, the only thing that wasn't clear is that you stated in one paragraph that you highly recommended he not clearcoat the aluminum then in the next paragraph you told him to clearcoat. That's why I said "huh?".......eh. :wink:
 
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