[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 The reason that so much gear was originally made with veg tan leather was due to animals (especially horses) and humans experiencing adverse skin reactions to the chromium salts-- and not a corrosion issue at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. I did not write the above information. I merely copied and paste, but it fairly well echoes my opinion.