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A little information from a reddit post about chrome tanned leathers and chromium salts possibly causing corrosion. Copied the text below in case the post disappears or is otherwise inaccessible. Use at your own risk as there is no chemical information to back up the statement, but was made in good faith by the OP based on his research and conversations with a person that should know. Tom https://www.reddit.com/r/Leathercraft/comments/4y005l/solved_can_chrome_tanned_leathers_be_used_for/ Posted byu/B_Geisler Old Testament Mod 4 years ago [SOLVED] Can chrome tanned leathers be used for knife rolls/ sheaths, holsters, etc.? OR Are residual chromium salts/ alum/ iron salts in tanned leather corrosive, and if so, to what metals and to what degree? Tips & Tricks Can chrome tanned leathers be used for knife rolls/ sheaths, holsters, etc.? OR Are residual chromium salts/ alum/ iron salts in tanned leather corrosive, and if so, to what metals and to what degree? This question gets asked here with considerable frequency, especially when it comes to making items that will come in direct contact with metals-- sheaths, knife rolls, holsters, &etc. Barrels and blades, folks. Conventional wisdom says that we don't make these items from chrome tanned leather, supposedly due to the corrosive nature of residual chromium salts in the leather. I'm guilty of this one. I've said it, I've heard old timers say it, and you can't swing a cat without hitting an internet 'expert' that will agree. Chrome tanned leather is bad for barrels and blades. Right? I've asked chemists, leatherworkers, wholesalers, and retailers and the most common answer by far is "Chrome tan is supposed to be bad for barrels and blades, but I've never SEEN it." I've researched this topic extensively and, until now, have yet to find a definitive answer on the topic. I made a few calls and ended up on the phone with Tim Howes. Tim has worked in the leather industry for decades and has, at one time or another, worked for about every major tannery in the business. Tim currently works a technical sales consultant for Tannin Corp, a manufacturer and supplier of oils, waxes, fillers, slip agents and syntans for leather tanning, processing and finishing applications-- these are the guys that sell tanning liquors to essentially everyone in the business and Tim's the one answering the technical questions that make that possible. Per my conversation with Tim, there's a short answer and a long answer to the question. The short answer according to Tim, is no. Chrome tanned leathers from any of the big-name tanneries use such advanced tanning processes that the risk of corrosion or blueing from residual chromium salts is essentially none. The long answer is, no. The reason that so much gear was originally made with veg tan leather was due to animals (especially horses) and humans experiencing adverse skin reactions to the chromium salts-- and not a corrosion issue at all. While the salts ARE corrosive, they don't appear in high enough concentrations in tanned leather to pose any risk except possibly as a skin irritant. He said that he couldn't recall having corrosion issues arise with ferrous metals, brass, nickel plates, etc. and that copper is going to corrode anyway. After a thorough discussion with him about modern tanning processes, it became clear pretty quickly that the likelihood of residual chromium being an issue is very, very low. That said, he did caution that the same doesn't go for leathers tanned in non-commercial settings and tannages from less developed countries that don't follow modern tanning processes. The reason for this is that "you just don't know what these guys are doing, there's some, uh, pretty funky stuff out there. I mean chemically its all backwards, but it works somehow." Any corrosion risk comes from storing the gun/knife/etc. in leather-- the leather absorbs moisture from the surrounding air and creates a damp environment. Damp environments and metals don't mix. That's it. TLDR; For practical purposes, as long as you're buying your leather from a reputable tannery, feel free to make knife rolls/sheaths/holsters from whatever tickles your fancy-- chrome tan, veg tan, oiltan, etc. are all safe for use. EDIT: We're talking about this in the context of typical leather applications from reputable tanneries.

Hi guys, I have a buckle that's cast with zinc alloy and plated with brass. Wondering if there are any good rudimentary tests that I could run to see how well the plating will hold up. So far I've scrubbed a section with steel wool and am now soaking the piece in vinegar and the platting is still holding up. Obviously this isn't going to be an exact science, but I'm hoping to get a feel for its longevity. The hardware is going to be used on a bag that will experience some outdoor use (maybe some occasional rain), but nothing too serious. Has anyone had good experience with brass plated hardware? Thanks!

Hi folks! I'm a leather worker in Eugene, Oregon and have run across a problematic situation a couple of times with leather, making marks under or on the surface of fine steel blades. It's happened with a lower end production knife called 'The Seguaro Survival'. That time the rust was appearing before my eyes. It literally was like a viral growth and took considerable work to stop it before it did serious surface damage. I chalked that up to the quality of the blade. Lately I had another blemish appear on a blade. This one was a high end custom knife. The customer called after having the blade in the sheath for a month and said two small blemishes have shown up. He tried using a metal surface polisher to no avail. In this sheath, I cured the constructed sheath in a low heat oven for plenty of time. I'd hoped this would take the offending chemicals or interaction away. The sheath is lined with a 3-4 Hermann Oak. Outer is 7-8 HO. I used Eco Flo brown on the outer and on the lining. At this point I must assume the fault is with the Eco Flo. My mentor, Dave Shelgren suggested not dying sheaths and only Neetsfoot them. This would stop it, but would lend to a restricted product offering. Any thoughts? Thanks in advance, John.