In air, aluminum oxide forms nearly instantly. You have never seen pure aluminum, because it does not exist where a human can stay alive to view it.
Therefore, sanding is a useless activity, if the goal is to remove aluminum oxide. You can do it, but you can't stop it from reforming. I suppose it is possible the layer is reduced in thickness, but I am not buying that that matters. I don't like the idea of sanding terminals. You want then to have the flat machined surface they have leaving the factory o get a good bolted joint with as much contact area as possible. If the terminals are clean and un-corroded I would leave them alone. I suppose one might prove whether the resistance is changed for the better if you have a really good instrument to check it. But this will not be your garden variety multi-meter. The magic creme noalox, is alleged to pierce the ALO2 crust with zinc particles improving contact conductance and maintaining it for some time to come. I would like to see some sort of evidence of this that is not anecdotal. But it might be true. As discussed here ad nauseum, I believe in clean joints that are torqued properly with good quality flat washers. I think a conductive grease that excludes moisture may be a good idea. I am less fond of dielectric (high resistance) greases, but they may not hinder conduction much, as the current passes predominantly through crushed asperities - metal to metal contact. On Wed, Jul 30, 2014 at 8:57 PM, EVDL Administrator via EV < [email protected]> wrote: > On 30 Jul 2014 at 17:05, Dennis Miles via EV wrote: > > > Silicone dioxide is glass, and aluminum oxide is clay, which when > > heated becomes ceramic, for example... > > Maybe it's splitting hairs, but (even though I took freshman chem a LONG > time ago) I don't know that I'd say "aluminum oxide is clay." > > If I'm not mistaken, potter's clay contains aluminum compounds (silicates). > I think you can chemically extract Al2O3 from it. Maybe you could say that > potter's clay CONTAINS aluminum oxide, but aluminum oxide isn't clay per > se. > > I would further disagree with "Silicone dioxide is glass," for two reasons. > > First, as with clay, glass does CONTAIN silicon dioxide. However, it also > contains other compounds, such as sodium carbonate and lime. > > And being a language stickler, I should also point out that the words > "silicon" and "silicone" are not interchangeable. Silicone CONTAINS > silicon, but silicone is not an element, nor does it occur in nature. It's > a synthetic (man-made) chemical compound. There is no such critter as > "silicone dioxide." > > To bring this back on topic, aluminum is not the best conductor, and > aluminum oxide is a pretty poor one. Unfortunately making al requires a > lot > of energy to reduce the bauxite, and this high embedded energy means that > Al > is always in a big hurry to turn itself into aluminum oxide. > > To keep this from happening, you have to keep air away from it. In > practice, you apply your NoAlOx or other grease within moments after you > abrade aluminum terminals (and aluminum wire, if you're using it). In fact > the instructions with at least one of those glops tells you to slather it > on > the (aluminum) wire, then wirebrush the wire with the goop already on it. > > As a side note, aluminum's high embedded energy and eagerness to oxidize > also makes it potentially (pun not intended) useful to power EVs. In the > past, EV projects have tried out aluminum-air batteries. (Unique Mobility > teamed up with AlCan for one of them in the 1980s.) > > There are big problems with al-air, though. For one thing, they're primary > (non-rechargeable) cells - in some ways more similar to fuel cells than to > batteries. Thus, you don't recharge them, you replace them, or at least > rebuild them in place. > > Also, al-air batteries aren't very efficient. They deliver only about 15% > of the energy that went into refining the aluminum. I don't think that > includes any energy use factors for transporting the alumnum to where the > EVs would load it in, so that would make for a further efficiency hit. > > David Roden - Akron, Ohio, USA > EVDL Administrator > > = = = = = = = = = = = = = = = = = = = = = = = = = = = = = > EVDL Information: http://www.evdl.org/help/ > = = = = = = = = = = = = = = = = = = = = = = = = = = = = = > Note: mail sent to "evpost" and "etpost" addresses will not > reach me. To send a private message, please obtain my > email address from the webpage http://www.evdl.org/help/ . > = = = = = = = = = = = = = = = = = = = = = = = = = = = = = > > > _______________________________________________ > UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub > http://lists.evdl.org/listinfo.cgi/ev-evdl.org > For EV drag racing discussion, please use NEDRA ( > http://groups.yahoo.com/group/NEDRA) > > -- Put this question to yourself: should I use everyone else to attain happiness, or should I help others gain happiness? *Dalai Lama * Tell me what it is you plan to do With your one wild and precious life? Mary Oliver, "The summer day." To invent, you need a good imagination and a pile of junk. Thomas A. Edison <http://www.brainyquote.com/quotes/quotes/t/thomasaed125362.html> A public-opinion poll is no substitute for thought. *Warren Buffet* Michael E. Ross (919) 550-2430 Land (919) 576-0824 <https://www.google.com/voice/b/0?pli=1#phones> Google Phone (919) 631-1451 Cell (919) 513-0418 Desk [email protected] <[email protected]> -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20140730/612c2059/attachment.htm> _______________________________________________ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA)
