6 replies to this topic

[tblade0123 TT Member]

Hey guys I am getting a bunch of things Hard Anodized and Anodizing some myself.  My question is does anyone know why type of Aluminum is used for the Swing Arm, fork tubes and shock body?  I didn't think it was a big deal, but the hard coat company said it would help if they knew.  

Thanks,

Blair

[grayracer513]

The problem with things like the frame and swing arm on many bikes is that they aren't made from one kind of aluminum.  Yamaha in particular blends castings, extrusions, and milled billet parts into their frame assemblies, which gives them tremendous advantages in terms of production and control of a number of the performance attributes of the finished product.

Shock bodies are usually cast.  Fork tubes usually from billet tube stock.  Note that castings don't take as well to anodizing as extrusions or billet parts.  And anodized swing arm from a YZ, for example, is apt to look like it's two different colors.

What bike are you working with?

[Kgmx856]

The anodizing (if you're adding color) also depends on the shine of the product. I had a guy who does anodizing in his garage do my TT drz case guards in blue. It was just the raw rolled aluminum. It came out dull grainy blue. If you were to do the swinger like that, it would be similar. Fork tubes will look like they do now. The shock body will look awful. I saw the finished product of cast CBR rims in red, and it was awful.

Then again, if all you're wanting to do is a clear hard ano, go for it. Although the fork tubes are already anodized.

[KJ790]

Here's my take from the plating side (I'm currently an industrial engineer at a plating factory that specializes in anodize and hard anodize). Like the others have said, the alloy does matter, but a good plater should be able to figure out what aluminum it is when they go to clean the parts. 2000 series aluminum tends to anodize like crap. Even when it starts as a nice billet part, it will often have pits, blisters, streaks, and overall crappy apperance after anodizing. 7000 series aluminum is also hard to make look good, but it is possible. If they use any titanium hardware to hold a 7000 series aluminum part then it will come out like crap. 6000 series aluminum anodizes the nicest, and you can use titanium or aluminum hardware to rack it.

As for castings, not all castings are the same. Something like an A206 casting will anodize quite well, especially hard anodize. We do a lot of black hard anodize on castings like this. They will often come out with a grey-white powdery appearance, but a scrub with a brush in some hot water or a quick blast with low pressure plastic media will make them look nice and black. Some other castings will not anodize well at all. If you just want a natural undyed grey color then they are alright, but if you want them dyed then they will look like crap.

Frames and shock bodies tend to take hardcoat alright from what I have seen, but I have not anodized any myself.

[tblade0123 TT Member]

These parts would all be Hard Anodized Black.  The Swingarm is being lightly shot blasted with stainless steel, he's hoping that will give it a more uniformed look.   Well crossing my fingers!  Haha.

The bike is a 2010 KX450f, I am thinking the swingarm is two different types of aluminum like mentioned above.

[KJ790]

Your anodizer is going to blast with stainless steel? I would recommend against that, stainless steel can get embedded in the aluminum can cause pits and other issues with the anodize. Most bikes come with the swingarms clear anodized these days, so that will need to be stripped first.

If it were me doing it, I would strip the anodize first, then go through a desmut/deoxidizer. The swingarm should look uniform, but will be a bit dull from stripping the original anodize. Hard anodize will make the finish even more matte beyond that. If you really want more of a matte finish I would go through a satin etch, or media blast it with glass bead. If you want a really rough looking finish then blast with aluminum oxide before the hard anodize. All media blasting should be done in a cabinet that has never been used to blast steel or stainless steel. The media should also have never been used to blast steel or stainless.

Make sure that all threaded holes and bearing pockets get masked off before the hard anodizing so that you do not have dimension issues when you go to put the bearings in or thread in bolts.

Edited by KJ790, 11 June 2013 - 01:44 PM.

[tblade0123 TT Member]

Well parts came out very dark grey/whitish.  Plus they didn't anodize the inside of the shock body (one of the main reasons for doing it).  Fork tubes came out great.  Now I left the parts saying I wasn't happy with them.  Specially the lack of hard anodizing inside the shock body.  I wish I would of tried to scrub them a bid and see if they darkened up.  But I think they wouldn't of.   Now I have contacted Racetech and they say the guy that does there KYB shock bodies gets them blacker than night.  He's sending me some pics now.   Have a bad feeling my bill at the anodizing company is going to be through the roof, as they keep with the "well we could do this but thats your decision".   Argh.  Hot mess.