Ok so I have been making puukko's for a while now, I love making the traditional sheaths, wet formed over a wooden lesta and back stitched but lately I've been going nuts trying to resolve a recent problem I have been encountering. I first noticed the issue on a purple heart handle (a poor choice for color retention in the long run, I know now) I began to notice that the section of handle inside the sheath was paling, losing its purple color and basically turning brown. The handle outside the sheath is still a nice rich purple. I wasn't hugely worried about it initially, its my own knife and a user at that so color change doesn't affect its performance. It grew more noticeable over time however and I began to worry about why it was happening. Well a few weeks back I made a new puukko with bocote handle and traditional sheath to match, I put several coats of Formby's tung oil finish on the handle, and I mean 7 or 8, it just kept soaking it up. Finally I coated it with renaissance wax for good measure. Just today I noticed it TOO was beginning to show the same signs of losing its darker coloration where it was contacting the leather. The leather I use is from Tandy's, but its fairly high quality, imported from Italy and veg tanned. Its wonderful stuff to work with, it forms great and looks fantastic. It takes dye great too, but I have used it on both puukko's with the same result, the wood begins to pale after a few weeks where it contacts the leather. I don't add anything to the sheath outside of dyeing the outside, with pro oil dye. My question is this, is it normal for that to happen with puukko/pouch type sheaths? Is there a way to prevent it from happening? I'm wondering if the leather itself is just too acidic for this purpose. I suspect I may end up needing to do some more extensive sealing of the wood as a barrier to protect it but I would like to hear from anyone who might have had similar issues.
