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  1. #1

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    Metal getting eaten in developer or fix

    I have a film rack for tanks that I had to fashion a handle too, b/c the orginal one fell of. It was actually easy, as I bought a screen door handle and used two small bolts and nuts through the cage. Viola...or so I thought.

    I ran two batches of film this evening and noticed on the first batch the reels were really dirty. I thought it was strange, but didn't panic, so I wiped them down. Then on the second run of film, I noticed the reels were worse and that there was gold color flakes running all over the film. Lame. I got most of it off, though it was really everywhere. It quickly occurred to me the bolts were black and corroding, and it appears the handle is too.

    So, a few questions. First out of curiosity: What is it, and what is eating it? Then the more practical questions: is there hardware that will work for this? If it was flaking in the developer, any guesses if these metal flakes pose any adverse effects to my tank of developer (replenished). And/or any effects to the film I've processed (opposed to the obvious fact that there are flakes of metal on it.)

    Unless I'm missing something else getting eaten...I'm surprised at how much of this grit there appears to be so quickly.

    Advice and wisdom greatly appreciated!
    Attached Thumbnails Attached Thumbnails IMG00130-20100330-2214.jpg  

  2. #2
    KOG
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    It looks like the handle is aluminum or chrome plate, the screw and the nut are carbon steel, and the basket maybe made of stainless steel. When you combine dissimilar metals in acidic or base solutions, one of the metals will transfer to plate one of the other metals. Just like the chrome plating process.

    Make sure all the metals are the same, and it is best to use stainless steel.

    Kevin

  3. #3
    MartinCrabtree's Avatar
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    The reels,racks and tanks are made from stainless steel for a reason.It's high resistance to corrosion fostered by the chemicals.The handle has no such resistance.Remove it and fab something up from an old rack/reel or some stainless.If you go looking for some stainless use 301/302/304 stainless.It can be found here but you'll have to buy like 6 feet of it.It is handy stuff to have around if you like fixing stuff to overkill status.

  4. #4
    richard ide's Avatar
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    Type 316 stainless is the only metal recommended for photographic applications. All others will corrode.
    Richard

    Why are there no speaker jacks on a stereo camera?

  5. #5
    MartinCrabtree's Avatar
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    Well I didn't know that.316 aint cheap.

  6. #6

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    Awesome info guys. I obviously had no clue.

    Any idea on the possibility of it contaminating my developer? I'll find out sooner or later, but wondering if there's an obvious answer to that too?

  7. #7

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    And also any advice on uncaking it...I'm just seeing now the extent...stuff got everywhere.

  8. #8
    richard ide's Avatar
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    You developer may have become contaminated the second time you used the rack. Apart from washing it with nitric acid which I do not recommend from a safety standpoint, I suggest getting a small stainless steel wire brush from a welding supply shop and giving the whole rack a good cleaning.
    Richard

    Why are there no speaker jacks on a stereo camera?

  9. #9
    wclark5179's Avatar
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    Perhaps this will help:

    http://en.wikipedia.org/wiki/Galvanic_corrosion

    When I was in the Navy the ship I was stationed on was made from the main deck up of aluminum alloy and below was a steel alloy. Everywhere they met there was plastic that separated the two metals otherwise corrosion would take place. Certain chemicals, present in a solution such as water & types of metals can speed up the process, the article in the link above addresses those and others.

    Hope this helps you.
    Last edited by wclark5179; 03-31-2010 at 07:37 AM. Click to view previous post history.
    Bill Clark

  10. #10
    Mike Wilde's Avatar
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    Back in college I had a job picking steels, including stainless to crane in from a storage yard in to a fabrication shop for cutting for manufacture of pulp and paper and sewage treatment and mining gear.

    I used to sort offcuts as they came back into 316, 316LS, 304, and a real exotic one 254smo, and then periodically have to test them with some mega nasty acids and bases to make sure the stuff was grease pencil marked correctly.

    The 254smo stuff was dear enough we even used to keep the drill and saw shavings along with too small offcuts and sell them back to the distrubutor.
    my real name, imagine that.

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