Author Topic: Anodising a nex aluminium frame  (Read 528 times)

Anodising a nex aluminium frame
« on: 16 June, 2022, 05:22:51 pm »
I am sure that this subject has come up but probably in relation to an existing painted frame.
So, given a new, unpainted, aluminium frame would it be possible to get it anodised rather than painted? What would be the drawbacks? Would it be less hassle than trying to get the right etching uncercoat to paint a frame?
Also is it practical to powdercoat aluminium?
I am going to put in an order for an unpainted frame and am looking at the options. My Vitus 992 is anodised as far as I can see and I like that finish.

LittleWheelsandBig

  • Whimsy Rider
Re: Anodising a nex aluminium frame
« Reply #1 on: 16 June, 2022, 05:44:41 pm »
Most modern Al frames are welded (7005 or 6061) and weldable Al usually doesn’t anodise very well, particularly around the welds. The old Vitus and Alan frames were bonded together with higher strength Al (7075?) which anodises nicely.

In addition, a welded bicycle frame is quite large and requires a similarly large anodising bath while individual tubes only need a small bath.
Wheel meet again, don't know where, don't know when...

Re: Anodising a nex aluminium frame
« Reply #2 on: 17 June, 2022, 08:20:16 pm »
Most modern Al frames are welded (7005 or 6061) and weldable Al usually doesn’t anodise very well, particularly around the welds. The old Vitus and Alan frames were bonded together with higher strength Al (7075?) which anodises nicely.

In addition, a welded bicycle frame is quite large and requires a similarly large anodising bath while individual tubes only need a small bath.

Thanks LWaB that solves the question very nicely. I was wondering about bath size but hadn't thought of Vitus frames having the tubes anodized before fabricating the frame (not  frame that there aren't professionals with big enough baths of course - if one can find them). But the fact that a 7005 alloy isn't suited to the treatment rather finishes the subject. Oh well, have to see my preferred paint supplier for some etching undercoat; they're good at that sort of thing!

LittleWheelsandBig

  • Whimsy Rider
Re: Anodising a nex aluminium frame
« Reply #3 on: 17 June, 2022, 08:27:45 pm »
Don’t take me as gospel on this. This sort of thing is well away from my main interest but I hung around frame-painters and other interesting folk in my misspent youth.

There are ways around some of the hassles if they use the right TIG rod and are careful but most won’t spend the time and money needed. You won’t know what TIG rod has been used anyway.
Wheel meet again, don't know where, don't know when...

rr

Re: Anodising a nex aluminium frame
« Reply #4 on: 17 June, 2022, 10:13:22 pm »
The black rose is anodised.

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Re: Anodising a nex aluminium frame
« Reply #5 on: 19 June, 2022, 11:11:21 pm »
Don’t take me as gospel on this. This sort of thing is well away from my main interest but I hung around frame-painters and other interesting folk in my misspent youth.

There are ways around some of the hassles if they use the right TIG rod and are careful but most won’t spend the time and money needed. You won’t know what TIG rod has been used anyway.

The frame in question is 7005 and welded in Taiwan; I would hope that the rod used was chosen for the suitability of its mechanical qualities for welding bike frames (and not for responding to questions about anodising); beyond that I suppose that the essential factor in choice is cost!
7000 and 6000 requiring radically different heat treatments (iirc reading in a fabricant's tech doc - probably Columbus) I would expect them to also have very different responses to anodising (since they are basically very different alloys).

The black rose is anodised.

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I looked on what I presume to be the correct maker's site and I couldn't see what tubes they were using other than steel (Columbus). I couldn't work out anything from the tubing stickers, sorry!

rr

Re: Anodising a nex aluminium frame
« Reply #6 on: 19 June, 2022, 11:47:13 pm »
The black rose is anodised.

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It is labelled 7005 T6

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gibbo

  • Riding for fun, cake and beer.
    • Boxford Bike Club
Re: Anodising a nex aluminium frame
« Reply #7 on: 20 June, 2022, 01:29:19 pm »
I had my ali frame (originally painted) anodised blue and it came out great on all of the tubing and most of the welds. Some of welds had the same colour as the frame whilst others were quite dark, almost black.

Since you probably won't know what weld stick material was used you won't be predict the colour until it's been anodised.

That said, the weld and subsequent grind back on my frame is pretty good so the black banding is a consistent size and doesn't really detract from the overall appearance.