Quote:
Originally posted by winewood
I have seen some people RAG on others for putting brass barbs in their blocks. They said it was adding another metal to the gavanistic corrosion tantrum. Sounds like the little brass that makes up the barbs is nothing to the brass comprising the hc.
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Some people included myself. You have to understand the situation. You leaving a HELL of a lot of details out and trying (maybe unintentional) to generalize.
First off putting brass barbs on a AL block that is not anodized is not good. Why? because the metals are
pysically touching each other. Bad stuff happens when you throw water into a mix of metals touching each other that don't react well with each other.
Second how is a Heater core connected to the block? Through hose and water. The only thing that can cause issues is the water that connects the brass core to the AL block. Being the metals are not pysically touching the effect is not as substantial as if the metals are pysicaly touching being the corrosion process has to happen through the water. And it will, just takes more time.
Third, even if the block is well anodized, the threads on a brass barb are sharp. They can slice right through the anodizing layer and allow water to seep in. If that happens the corrosion effect can actually go UNDER the anodizing layer. Like rust under the paint of a car. Can simply be worked around with plastic or non brass barbs.
You can simply add anti corrosive materials to the water, but then it is still just a matter of time. If you take steps to limit cross metal contamination in the first place and use anti corrosives then your as good as your going to get. If you use all brass/copper you can even get away with just distilled water for a long time (long time meaning a few months or so). AL on the other hand is pretty nasty, if it is not anodized. It gets ugly fast if you don't use anti corrosives. Aluminum has a terrible oxidation problem. It should simply not be used, but if it is then use anti freeze or similar. Even if you DON'T have brass/copper in the system AL will cause issues. Brass/Copper will to but it takes a hell of a lot longer. AL will however work and work decent as long as anti corrosives are utilized.
This is how I come to understand it from a non scientific point of view. If I am wrong please correct me. I am sure some of this is not completely accurate.