I have been using aluminium flat to connect screw mount reservoir capacitors in my power amplifier power supply. I prefer aluminium flat as it is clean and tindy with far less soldering to do. Conductivity is excellent given the thickness and width of the aluminium flat.
However, I have just looked up aluminium in Wikipedia, and found that aluminium when exposed in air forms a thin layer of aluminium oxide in a fraction of a second.
I am wondering if contact resistance is high with aluminium due to oxidation and whether it is a good idea or not to use aluminium flat or not.
However, I have just looked up aluminium in Wikipedia, and found that aluminium when exposed in air forms a thin layer of aluminium oxide in a fraction of a second.
I am wondering if contact resistance is high with aluminium due to oxidation and whether it is a good idea or not to use aluminium flat or not.
Clean the mating surfaces with a fine abrasive and connect together asap . I have seen plank like bus bar joints filed through a layer of vasaline to inhibit the oxidation , the surfaces then cleaned with more vasaline and the joint made and checked with a moving mirror galvanometer , but thats a bit extreme as they were going to carry hundreds of Amperes.
Thanks for your input.
My worry is that from the Wikipedia site it says that the oxidation occurs within a fraction of a second (in pS) and it is all done.
In theory, the oxide reduces conductivity. In reality, the multimeter does not show resistance. But then I can't trust the multimeter because it does not have the resolution.
I guess the safest way to do it is that the connection to the PCB is directly connected to the last cap's screw terminal, rather than on the aluminium flat. The small resistance between the caps probably does not matter.
My worry is that from the Wikipedia site it says that the oxidation occurs within a fraction of a second (in pS) and it is all done.
In theory, the oxide reduces conductivity. In reality, the multimeter does not show resistance. But then I can't trust the multimeter because it does not have the resolution.
I guess the safest way to do it is that the connection to the PCB is directly connected to the last cap's screw terminal, rather than on the aluminium flat. The small resistance between the caps probably does not matter.
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