GTA
General Discussion To Gateway To Airguns => Gamo Gate => : cnsjones July 06, 2009, 10:01:56 PM
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I read this post while becoming familiar with the site (i am a newbie here).
As an engineer, I remembered somethin about Copper/Steel galvanic corrosion, and commented on the old thread. In the off-chance that others might try that method, and missed my comment, I offer the following:
Copper and steel is somewhat galvanic.
See: http://www2.mtec.or.th/th/research/famd/corro%5chowmetals.htm#table...
The relationship is shown in Table 2 near the end of the article.
You may end up with some corrosion that you do not like. CDT, what do you think?
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Well Fuller, I am not CDT but learned many years ago about mixing certain metals and the corrosion that would follow. That is a great chart you have there.
May I use it in the GTA Library
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Hey Gene,
Don't see why not-- It is on the Web at the site I linked. What I usually do in putting such like on a permanent page ior in a book or article I am writings to simply show the source. In this case there is NO copyright notice, and the source is not readily available. BEFORE I POSTED, I searched the following link, which was shown on the Google entry that I found the article on. http://www.mtec.or.th/th/research/famd/corro%5Chowmetals.htm
All that gave me was the exact page I linked. I looked up "mteC.or.th and found that it is a foreign entity in Indonesia. as is "Chow Metals"--- I was unable to come up with anything else.
I am sensitive to copyright issues as i am an author of sorts, and am very careful.
In this case, as Kiwi would probably say: "NO WORRIES MATE!"
If anything at all, I would put "Internet Source Accessed July 2009" after the article or whatever part you want to use.
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I just posted some follow-up information on that thread http://www.gatewaytoairguns.com/airguns/forums/thread-view.asp?tid=16951&posts=32#M158267 as to my copper end cap. So far, so good. I will keep an eye on it, however, I wonder if the blueing of the rifle's action offers up enough protection that the metals do not experience the galvanic reaction. Worst case I would think that if the copper endcap was coated with something thin (paint?) it would prevent the reaction as well. Thinkin' out loud...
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Notes on Bluing
Bluing is a chemical conversion coating, and is typically no thicker than 0.0001 inch;
plating provides better protection against wear and corrosion.
Gun bluing will provide limited resistance against rust of the gun, and will only slightly improve surface durability
to reduce susceptibility to scratches.
All blued parts should be properly oiled to prevent rust.
PM to Gene
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See Attached (If I can do it right!)
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Ok Fuller, I got it and will post it in the GTA Library. Thanks for your chart. It will come in handy for those who want to put bling on there air guns.
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One thing that I noted of interest in that table is that is doesn't tell you that galvanized steel is overlayed with a thin layer of Zinc. Also, it only address active stainless steel, and doesn't really show regular iron or steel. One other thing to remember is that in order for the galvanic reaction to occur, some sort of electrolyte needs to be present in order for the two metals to electrically couple (this is mentioned in the article you posted).
Where I am here in Colorado, atmospheric humidity is usually quite low (~20% most of the time), so that would slow any potential corrosion. Also, some sort of electrically resistive grease could be used between the two parts to further isolate them, which would also prevent moisture penetration.
PS - FWIW, I am an aerospace engineer and deal with this kind of stuff all the time for a living. IMHO, the table you posted is almost too basic and doesn't give you enough information about the reaction potential.
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I agree 100% that it is basic info. I also am an aerospace engineer (retired) and ignored the fundamentals that you correctlyu point out. I am in Florida on the Space Coast, and we have one of the most corrosive atmospheres around with a prevailing seabreeze from the Atlantic. Those in a dry climate need not worry as much. Your points are well taken.
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I was wondering if you were also an AE. Nice! Betcha can't guess what I'm working on right now... 8)
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Almost 35 years at Uncle Sammy's Rocket Ranch launching the things. Started with ABMA in Huntsville with the Von Braun team (1958)Almost 40 years in aerospace all told (retired in 1995).
Don't have a clue (what is in Colorado??-- you at Lockheed Martin??) but I HOPE/WISH it is missile defense!!!
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That is cool! Those were the heyday of rockets! I work with a few guys from the Apollo era and love to hear some of their stories. I am working on the next big thing to get launched at the cape - Orion (yes, at LM).
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As a follow up on this, I recently removed the endcap and have no corrosion of any kind showing.
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and that it in fact does nothing to hold the pin? Im going to have the same issue when I do mine but Im probably going to cover the opening a different way without considering 'holding" the pin.
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If your talking about changing stocks on your whisper to the hunter 440, I think they have changed it, at least the one I got they had, I did not have to use the copper end cap, I was able to use the plastic one that came with my whisper.
Jeff
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I mentioned in another thread; looks like they switched the 440 design to match the newer stocks. Likely the reason you can get a wooden Whisper from the factory.