I’ve searched and haven’t come up with much and I’m not sure if this is the right place to ask. But, I'm considering having my mountain bike frame hard anodized over the winter. Hard anodize will be much more resilient than paint. But, will it be lighter? What about powder coating? I can have it media blasted (soda) and finished locally for less than $150.

I’d rather go the hard anodize route rather than color anodize due to durability and I like the olive green that hard anodizing yields.

I don't know the ramifications of anodizing on bikes, but anywhere else, it is the best finish for aluminum, hunting, marine, climbing. Hard anodizing can be done in a wide range of colours, bright, black, etc... It would be light since it is very thin, though worrying about the weight of paint or even powder seems a stretch. I assume your frame is aluminum.

A word of warning - aerospace frowns on hard anodizing unless it's entirely necessary as it can reduce the fatigue life of especially aluminium alloys (it's due to the difference in hardness and brittleness of the respective thick, dense coat of alumina to the soft, ductile parent metal) by as much as 40%.

And as for hard anodizing aluminium parts for a marine environment? I'd say no, actually. There's a reason why the navy paints its aluminium parts, not anodizes them.

Just wonder how expensive that could be. I would send that to powder coating but a really good one because it could be cheaper than anodizing?

Aluminum arrows, and bow risers are anodized. Arrows are heavily loaded, way beyond what a frame is. I wouldn't worry about it on a frame. Easton one of the big providers to the cycling industry uses a lot of anodizing, but I don't know what they use for bike tubes, since if it is to be welded, it wouldn't be pre-finished. As Falanx says, it has come up as a stress riser, and people criticize it on rims. So you take your best bet.

Marine wise, it is ubiquitous. US navy does a lot of good things and a lot of bad things. Cost is a big part of that, but they use both highly disposable stuff and stuff that is really expensive. Certainly anodization is used heavily in yachting as is stuff that looks like epoxy coating.

What is the norm on cycling parts? Seems like a lot of parts look anodized, but they tend to be thicker section than tubes just for starters.

The anodizing I'm thinking of trying is Type III/Industrial Hard coat, 1 to 3 mm thick. No coloring avaliable except for black and olive green due to the increased thickness of the anodized layer. The anodizing process for industrial hard coat is on and in the aluminium, where Type II/Type I anodize is just surface and thin.

No marine enviroment to worry about for me, I'm in a semi arid climate.

Type III/Industrial Hard coat, is 1 to 3 nano meters thick....not mm

It's 1-3 microns thick, not nanometres.

Third time lucky? :-)