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Thread: copper scales??
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11-04-2009, 04:19 AM #21
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11-04-2009, 04:25 AM #22
I took 3 mm black acrylic and superglued it to the copper for added strength (thought about using just the copper but it seemed to bend too much). Also, the idea of unlike metals touching seemed like a case for corrosion so enter the acrylic sheet (found at Tap plastics here locally).
I thought by thining the copper I could lessen weight (which may have occured but unsure) and just happened to get a cool effect in the process that I liked
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11-04-2009, 04:22 PM #23
I love the way these look, especially with the pitting! I'm looking forward to seeing pics of the assembled razor. Well done, sir.
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ElChatico (11-05-2009)
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11-04-2009, 11:24 PM #24
Very very nice! The acrylic liner, maybe a different metal in the pivot pin and washer, and it sounds like you won't see any electrical badness. Again, very nice!
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ElChatico (11-05-2009)
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11-04-2009, 11:37 PM #25
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Thanked: 324I think the worries about electrolysis are largely unfounded. How many steel razors have had their brass pins eaten away by electrolysis? Even over the course of a couple hundred years, I've never seen it become a problem in vintage razors. That goes for the wedge end, also, which were often brass pins with lead wedges.
Now put those into an ionic solution of electrolytes and pass a mild current through them and you've got problems when the disparate metals act as electrodes. But that's not what we do with our razors.
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11-05-2009, 01:11 AM #26
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11-05-2009, 01:36 PM #27
Galvanic corrosion can be a real problem. You can see it all the time in buildings: plumbing connections of different metals without dielectric fittings, or pipes running through steel stud walls.
For pins holding a blade, it is a very small surface area, so the corrosion would just be where they are actually in contact, After the surface corrosion forms, it protects against further corrosion, as the corrosion/rust is not very conductive. How often have you seen shiny brass pins in a shiny steel hole in a razor? They have a small protective layer of surface corrosion.
With copper scales, the whole length of the blade is susceptible. Granted, the entire length would not be in direct contact with the scales, but where they touch near the spine would very likely be pitted. And every time you would clean the blade, removing the corrosion, a clear path for ion transfer- and more corrosion- would reappear. The acrylic is a very good idea.
If anyone is interested, here is a good link regarding metal compatibility with regard to galvanic corrosion:
http://www.engineersedge.com/galvanic_capatability.htm
Sorry for the boring post.
Matt
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ElChatico (11-05-2009)
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11-06-2009, 01:04 PM #28
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Thanked: 324
Didn't mean to rain on anyone's parade or get anyone cussing on their soapbox. I'm just saying I've seen brass pins used in razors and knives for centuries. Brass washers have been used in razors for a couple hundred years at least. (they're the real contact point for the spine/scales, anyway). I've seen silver scales that didn't destroy the razor and I've seen old guns with gold inlays that seemed to survive the galvanic corrosion that should have caused. I wasn't challenging anyone's expertise or trying to prove anyone wrong. Just saying brass/copper have been used in cutlery applications for a long time without serious problems. Sorry if I ruffled anyone's feathers or challenged anyone's authority.Last edited by PapaBull; 11-06-2009 at 01:11 PM.
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11-06-2009, 02:25 PM #29
Hey Robert-
The soapbox was meant to be sarcastic...and I have no authority here.
Like I said, a small coating of corrosion can stop the galvanic reaction, when things are dry and exposure to air is limited.
With pure copper scales, the removal of corrosion from the blade would allow the reaction to continue. Also, really drying the razor each time would have extra importance.
The brass pins would survive, of course. It is the steel, which is more anodic, which corrodes. Again, not a huge deal at the pin end, but worse at the blade. And brass reacts less with steel than does copper.
As an aside, I do have several old Sheffield blades where there is a steel collar between the brass pins and the steel blade. I assume the collar is to take whatever corrosion comes about, instead of the blade.
Keep your blade dry and keep cleaning it, be viligant, then copper scales may not be a problem. Or add an acrylic backing, and avoid the problem entirely.
The pipes in the wall analogy I gave has the worst of both worlds: water, lots of area exposed to air, and no one seeing it within a wall. Bad news.
Didn't mean to cause a fuss, either,
Matt
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11-11-2009, 06:19 PM #30
Awesome looking scales! I was about to comment on how the oxidization might adversely affect the blade, but I see in reading further you've addressed this already! Very cool.
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ElChatico (11-12-2009)