Advice For Building Custom Water Blocks?

I'm planning on adding my first watercooling loop to my PC. Thinking of manufacturing my own waterblocks, and was looking to get some other peoples opinions on my designs and plans.
A subject of, I suspect, some controversy, is that I think I'm going to make them of aluminium. This is mostly due to the cost of copper, and the fact that I happen to have a slab of aluminium lying around. I understand it may not be as efficient at cooling as copper, but my real concern is galvanic corrosion from mixing metal (copper in the radiator). I've read in various places that annodising the material will stop this. Does anyone have any experience with this?

Here are some pics of my designs so far.

I'm afraid I can't answer your question - but if you can do it, then very fair play to you - you are obviously very skilled!

I think it maybe a case of try it and see how it goes ...

I'm actually debating the same thing, JR23 seems like the man to Ask - I'm sort of interested in a large 6 x 5.25" panel for my new 8pack Lian-Li... that's more simply though as it's a res not block.

Nice designs though, I'm trying to learn Sketchup but have no time right now...

You will very likely get galvanic corrosion first around the fittings you screw into the aluminium. These will be nickel plated brass, the nickel will go first before the aluminium. You can avoid this by making the top out of a plastic material, i.e. acrylic or acetal, so you'll need a block of that too. To be honest I don't know why you are concerned with cost of a block of copper compared to aluminium, if you have the tools and skills to make a block then the time and effort surely will vastly outweigh the few quid it would save on not having the most appropriate material.

I get what your saying, but the time I'd spent doing this would only be slightly more using alu (if it goes right and doesn't break everything) and as its something I'd enjoy the time doesn't bother me. I think you're underestimating the cost of copper. To get enough of it, in the right dimensions I'd be looking at over £100, whereas I have tonnes of aluminium just lying around. Unless you know a place to buy cheap copper, which would be awesome.
Finding scrap and melting it down did cross my mind, but then I'd have to build a furnace and get a crucible etc etc and that's getting silly.
As far as corrosion goes, around the bolts doesn't concern me too much as they can be painted, its where the liquid contacts the block thats the problem.
I've more or less decided that this wont work unless I can get aluminium radiators, which I'm having trouble finding in the UK. Dont suppose anyone has any ideas? Koolance seem to do good one but shipping from the US is astronomical

It's tricky isn't it. On the one hand you have a desire to make something from scratch to fulfil some kind of Fred Dibnah/Isambard Kingdom Brunel type fantasy, using the fact you have some materials lying around, whilst agonising over the obvious shortcomings regards trying to make everything else in the loop fit around the one thing you want to make yourself. And on the other hand you have an EK CPU block you can buy ready made and of professional quality for about £50. It's an age old story seen it many a time in the water cooling community. Also painting your fittings wouldn't work, the paint would go when you screw them in, then water will get at the threads, instant galvanic loop.

You could plate your aluminium block after it's done and/or introduce a corrosion inhibitor to your coolant.

@Bubo, you've summed it up perfectly.
@LePhuronn, I've read that aluminium doesn't electroplate well but I might look into it again.

I did find some super cheap "chinese ebay special" aluminium radiators, but that would probably end badly.

Shortly after posting I remembered reading alu doesn't plate very well.

There is still the corrosion inhibitor though. I think Mayhems X1 actually has corrosion inhibitors in it already.

Better to melt down a load of cheap copper and cast it?