Material for custom header? (quick answer appreciated)

[Top Nurse]

Need to know something fast. I am using a HWL cooler which I assume is made out of copper, correct? However, when drilling the attached mount the chips look like brass and the fins look like copper.

If I make the part out of aluminum will I have major corrosion problems or is this modified by the use of anti-corrosion agents such as the Super Coolant I currently use? I can electrically isolate the header from the system by using non-conductive materials to mount it to my case.

 

[HeThatKnows]

What HWL cooler and what exactly are you trying to do?

 

[Top Nurse]

I'm using a 120mm HWL radiator (see link above I just edited in and scroll to bottom of page) and I will be making the adapter you see in the pic. The fittings are nickel plated brass and the block material I use is the question

 

[HeThatKnows]

Your rad has brass tanks and sides and copper fins.

You'd be better of making your splitter out of brass (and nickel and/or chrome plating it, if you like).

Aluminum is a corrosion risk, particularly where you have a good mechanical interface (like threads). Corrosion inhibitors do/will help, but with fittings there's the tendency to have a small amount of coolant stagnate in/around/near the threads. The stagnant coolant will deplete its inhibitors fairly quick.

Another thing is the ratio of anode/cathode suface area. Your cathodes (the brass interior of the rad/the gold-plated interior of the blocks) have a lot more wetted surface than your splitter would. Make your splitter from Al and you concentrate all the potential for galvanic corrosion into a small area, which has the possibility of it being eaten fairly quickly.

Edit: If you don't feel the need to use metal, delrin is an awesome plastic to use.

 

[zer0signal667]

Another thing is the ratio of anode/cathode suface area. Your cathodes (the brass interior of the rad/the gold-plated interior of the blocks) have a lot more wetted surface than your splitter would. Make your splitter from Al and you concentrate all the potential for galvanic corrosion into a small area, which has the possibility of it being eaten fairly quickly.

Edit: If you don't feel the need to use metal, delrin is an awesome plastic to use.

This is exactly the reason why I don't trust anodized Aluminum - it often has small pores that can corrode in a pitting manner. I would go with copper if you prefer metal, it will be compatible with your other parts and fairly easy to machine if all you're doing is drilling and tapping. Delrin is indeed a good plastic, Nylon of HDPE (high density poly-ethylene) would probably also work pretty well. You'd want to stay away from brittle plastics like acrylic or PMMA (Plexiglas).

 

[HeThatKnows]

Yeah, if you have any flaws in anodization, it just concentrates and accelerates the corrosion in that spot. That's how Koolance 'gets away with' using mixed metals -- the large area of bare aluminum in the rads spreads out the corrosion reaction, so that it would take a long time for any given point point to be eaten through.

 

[Top Nurse]

I thought the reason Koolance doesn't have a problem is because their coolers are gold plated copper?

 

[HeThatKnows]

Gold is even more cathodic than copper, which is why gold doesn't corrode (except very rarely). A gold/aluminum galvanic couple has a higher voltage and higher reaction potential than a copper/aluminum one. The gold is for looks, not usefullness.

Galvanic series chart ,with voltages, but they don't list gold.
Another galvanic series with gold listed, but no voltage potentials.

 

[Top Nurse]

Hmmm....my friend says he has some kind of plastic that is easy to machine so I think I will use that. Especially since Koolance isn't giving out the aluminum block headers in their EXOS II design. Maybe they know something we don't about their coolers and aluminum...