Igor, thanks. I was assuming that the majority of folks on the list would be in possession of rubbing alcohol rather then spectroscopic grade. :-)
But in any event, part of what makes contact cleaner a better idea than either pure or impure isopropyl is what it _does_ leave on the surfaces: anti-oxidant lubricant. That prevents the contact surfaces from re-oxidizing right away. On Tue, Nov 13, 2012 at 1:01 PM, Igor Roshchin <[email protected]> wrote: > > Bruce, > > Thank you. An electronic contact cleaner spray might be a good idea. > I didn't think about it. > > Just a quick comment about isopropanol. > You brought up an important point that can be overseen often. > However, for the purpose of "full disclosure", err. information: > The amount of residue left behind by an evaporating solvent depends > on the solvent, but even more depends on the purity of the solvent. > The 70% isopropanol that is sold at a pharmacy as "rubbing alcohol" > probably has plenty of impurities that don't evaporate. > > High purity (e.g. spectroscopic grade) solvents leave very small residue > (between 1ppb and 1ppm, depending on the solvent). > Isopropanol of high purity grades is frequently used for cleaning > Ultra-high-vacuum (UHV) components for the reason that it leaves very > small amount of residue on the surface, and also that it can be removed by > baking the surface. Methanol that is used for the same purpose, while > being more volatile overall, IIRC, may leave a bit more impurities behind. > > Many typical wafer cleaning procedures include IPA (isopropanol) or > methanol as the last step, - to remove residues left by other solvents, > e.g. acetone. > > > Igor > > > > Tue Nov 13 12:29:00 EST 2012 > Bruce Walker wrote: > > I use an electronic contact cleaner spray which I apply with a Q-tip. > Hosa D5S-6 DeoxIT, by Caig Laboratories. > > Dirty hotshoe contacts (and battery contacts too; don't forget those) > are the source of practically all my flash misfires. It similarly > affects the radio trigger devices. > > I'd be leery of using isopropanol though. Better than nothing, but I > have found it may leave a non-conductive residue. > > > On Tue, Nov 13, 2012 at 12:09 PM, Igor Roshchin <str at komkon.org> > wrote: >> >> >> In the recent past, my flash (Metz AF58-1) in combination with K-7 >> developed a problem. In some cases, I do not get the flash-ready >> confirmation symbol in the viewfinder. In other cases, even if I do >> get that confirmation at first, the flash (in PTTL mode) goes off full >> capacity, as if the PTTL did not work, yielding extremely overlit >> images. In those cases, often, on the subsequent shots, there is >> no flash confirmation symbol. >> >> All those problems can be fixed by tweaking the hotshoe in the socket >> (sliding it slightly in or out), but it takes a few times to find the >> "right" position. >> I am thinking if this can be fixed by cleaning the contacts. >> >> What are the options of cleaning the contacts besides the obvious of >> using a q-tip soaked in isopropanol? >> >> Any other thoughts on what else might be causing such hot-shoe issues? >> >> Igor > > -- > PDML Pentax-Discuss Mail List > [email protected] > http://pdml.net/mailman/listinfo/pdml_pdml.net > to UNSUBSCRIBE from the PDML, please visit the link directly above and follow > the directions. -- -bmw -- PDML Pentax-Discuss Mail List [email protected] http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
