I ordered several additional meters of nitinol and constantan wire (.8mm). It took some work to find similar diameters.
On Thu, Jan 24, 2013 at 5:52 AM, Jack Cole <jcol...@gmail.com> wrote: > Thanks for the suggestions Jones. I will give that a try. > > > On Wed, Jan 23, 2013 at 9:19 PM, Jones Beene <jone...@pacbell.net> wrote: > >> A combination of vinegar and hydrogen peroxide works with nickel-copper >> and is very safe. This is often used to etch PCBs. Using a few volts with >> the wire as cathode should also load H2. The muriatic may work better on >> Nitinol.**** >> >> ** ** >> >> This is not precise calorimetry – Terry… you can to call it “thermometry” >> and be sure to stir. Just a simple way to gauge the comparative ability to >> raise the temp of a known mass of water. Using the specific heat to arrive >> at joules and logging the P-in, you can get a ballpark but the basic idea >> is *comparative* between a wire that may be slightly gainful and one >> that may be slightly endothermic.**** >> >> ** ** >> >> The idea is to see if there is anything “obvious” there, before incurring >> the expense and time of doing it right. For instance, going from 25C to 75C >> in an hour with Constantan at (x)watts P-in vs. 25 C to 65 C with Nitinol >> (both wires of the same Ohmic resistance) and everything else being the >> same … that would be interesting enough to dig deeper, no?**** >> >> ** ** >> >> Ahern’s finding of anomalous endotherm with nickel-titanium is ‘out >> there’ in the public record and ought to be corroborated or debunked.**** >> >> ** ** >> >> *From:* Jack Cole **** >> >> ** ** >> >> I could run some low power electrolysis for a day or two in some diluted >> hydrochloric acid. Think that would do the trick? Or do you have another >> idea for the acid?**** >> >> Hydrogen loading will surely be necessary at some level, but can possibly >> be accommodated by combination of low pH electrolyte, not so low as to >> dissolve the wires… or preferably by preloading etched wires for a day >> under H2 pressure and modest heat, or even the simplest expedient which >> would be during a slow electro-etching in weak acid- with the wires as >> cathodes. The last would be the easiest to try for anyone without H2.**** >> >> **** >> >> ** ** >> > >
