Coating/finishing of ally panels

[GordonG]

OK, since I got such excellent information (thanks all) on bonding ally skins to tube frames I'l try my luck again:

Recommendations for finishing ally panels to avoid/minimise scratching and corrosion?

My first option is powder coat, though I'm concerned that this might be heavy and/or flake.

Anodising: Soft (sulfuric?) anodizing is just that, soft, and AIUI will not give much abrasion protection (and will therefore look cr@p after a bit of use).

Hard anodising would appear to give excellent abrasion resistance, but will it give me serious fatigue problems? (planning to rivet every 40mm plus Sikaflex on each tube the panel touches - probably no more than 300mm max between tubes)

Chromate conversion: this looks like it might be good but I can only find limited information and without being a metalurgist cant work out whether it is suitable.

Spray painting: Use an etch primer and spray with cellulose or 2 pack - likely to scratch and add weight, unless someone knows of a super whizzy (DIY?) paint/coating?

Leave au naturel: cheap (£0), light(0g) but allows the ally to corrode, scratch etc.

These are the options I've found so far. Can anyone shed light on the relative pros and cons of the above (inc relative cost) or suggest any alterntives? I am on a budget but I do want this car to look good and stay that way if possible.

Thanks

Gordon

[ChironWSC]

We anodize our panels saves weight and looks great also is very hard wearing. You should not have a problem with fatigue as long as you bend and shape all panels before you get them anodized. Lasts for ever looks great and is light what more do you want. I would not even consider paint or powder coating but dont know about the others in your post.

Henry

[GordonG]

Thanks Henry.

Is that Sulphuric anodizing or hard anodising that you're using? Just spoke to my local plating company, who recon hard anodising is used for bearings etc, not for panels, and recommended AA25 (25 micron) architectural spec in blue (since this lends itself to this thickness of anodising).

Any idea what ballpark cost I should be looking at for the panels on a sports racer tub (think Radical), and/or recommended suppliers? This is a one off build for me.

Gordon

[ChironWSC]

Gordon

We use Redditch Anodising (Keith) 01527 526855 they can do big panels and are based in Redditch West Midlands. I know that our panels are not Hard Anodised but i am not sure of the spec Keith will recommend like he did for use.
Cost around £150-200. The anodise is hard wearing compared to paint or powder coat and looks real good recommend Blue or dark red. Where are you based?

Henry

[Cameron Winton]

Hard Anodise is used for wear resistance in mechanical components and is very hard (AL oxide is a ceramic)and brittle. I would not use it for corrosion protection which is the normal use of anodize. Corrosion protection anodize can be dyed any colour you want. Chromate conversion is a paint on type process but the stuff is nasty and my experience is that it gets used on small areas only after the anodize has been removed by reowrk or repair. It looks horrible as well.