<html><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><div><div>On Jul 8, 2008, at 11:13 AM, Ken Zahringer wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite"><span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Garamond; font-size: 14px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0; ">Bluing is actually a chemical treatment.  The steel is immersed in a water-based chemical solution at or near the boiling point.  The hot solution promotes the chemical reaction, but it isn’t hot enough for the heat itself to do anything to the steel.  Look at<a href="http://en.wikipedia.org/wiki/Bluing_(steel)">http://en.wikipedia.org/wiki/Bluing_(steel)</a><span class="Apple-converted-space"> </span>for a good description of the process.<br><br>There have been “cold blue” products on the market for some time.  Gun owners commonly use them for touch-up.  As I understand it, these products produce the same chemical reaction on the surface as hot blue, just not as effectively since they operate at room temperature.  I always figured the pin blue stuff that Schaff sells was this sort of thing, but I have never used it.  I have no clue what the heck in on the nickel/blued thread pins.  That’s a color not found in nature.<br><br>Regards,<br>Ken Z.</span></blockquote></div><br><div>Hi Ken,</div><div><span class="Apple-tab-span" style="white-space:pre"> </span>Thanks for the info and link! Seems like bluing is even less important than I had thought, in terms of "functional utility" (I thought it might add a bit of surface hardness as well as minor rust resistance, though, come to think of it, the bluing scratches pretty easily, so I should have known that was wrong). In any case, I would say that none of the threads in the photos Kendall posted were blued. <br></div><div><br></div><div><div><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><div><br class="Apple-interchange-newline">Regards,</div><div>Fred Sturm</div><div>University of New Mexico</div><div><a href="mailto:fssturm@unm.edu">fssturm@unm.edu</a></div><div><br class="webkit-block-placeholder"></div></div></div><br><div></div></div></body></html>