Hi all, At the request of Joost Heijnen, I have created this guide to creating patinas, using yellow mustard, on your blades. In this example, I am using an Opinel #6, but you can use any high carbon, non-stainless steel blade. The idea behind forcing a patina onto your blade is to create good "blue" rust. A patina is a protective coating of blue rust that prevents the creation of bad "red" rust, which is the red/orange nasty rust you see on old car wrecks and whatnot. This guide will be split into two sections. The first section details how to create a rippled pattern, and the basics to create any patterned patina you want, basically. The second part creates similar results to those you would get from an orange/lemon, a very speckled pattern. Two key tips about using mustard though: a) Remember that it is not the area under the mustard that blues, but the areas around the mustard that oxidises into the patina. b) Mustard has a far quicker working time (in open air) than an orange, lemon, potato, onion etc pattern. Onto the guide. The Rippled Pattern The first step is to wipe down your blade, to get rid of smudges, oils, etc. If I intend to do a patterned mustard patina, I give the blade a soak in plain white vinegar for about an hour or so, just to provide an even coating of protection along the blade which the mustard application might miss. After giving it a good soak, I then arrange the blade so that it presents as much of the blade as possible The key ingredient. I use French's Classic Yellow Mustard. To apply a pattern, I typically use a cotton bud or fine point paint brush. The first layer of our rippled pattern. At a rough angle of 30ish degrees, I "draw" thin stripes along the blade. It doesn't matter if it's smudged, just don't glob it on. Come back in roughly 30 minutes time, rinse the blade under water, remove the mustard, dry the blade, and you get this: For some, this may be all you want. Rinse and repeat on the other side if you only want a single stripe layer pattern. To create the ripples, we then apply another layer of mustard at an alternate pattern to what we did originally. Wait another half hour, rinse the blade, clean it down, and admire your finished product (well, at least half the finished product). Note the blue tinges in the stripes: This is the good rust that we want to protect our precious blades. Repeat the above steps for the other side, and you are finished! The Speckled Pattern You do not need to give this method a vinegar bath, unless you so desire. Apply a generous amount of mustard to the blade, but do not glob it on. Using your cotton bud or brush, stipple the mustard to create something similar to this: Ideally, about half as what I put on. Oops. Wait half an hour, and admire your results! I botched the Opinel, but here is my Svord Peasant's Knife with the same technique: Happy Patina'ing!