EDIT: its been some years since I've written this tutorial and I've made a few minor additions to clarify some things. I've also learned that this method does not work with O1 steel; I've only achieved erratic surface pitting and harldy any rust. I've heard of 01 being vulnerable to rust but I just dont see how thats possible given my results with this method. By popular request, here is a tutorial on the process I use to 'rust brown' and 'blue' carbon steel. This method is still in it's infancy, and I am still working on the finer details, but I'll try to make this as comprehensive as possible. So, here we go... Materials needed ........................................................................................................ For the rusting: ---------------- 3% Hydrogen Peroxide (common household variety) Table salt For the bluing: -------------- Distilled water Accessories: ------------ Pot large enough to accommodate the object you are going to rust (do NOT use aluminum; stainless steel will work for this purpose but will likely rust; maybe a little, maybe a lot. Non-stick pans seem to be unaffected by the process, but your experience may vary) Toothbrush (for scrubbing and polishing) tongs (for moving and manipulating the item being rusted) Gloves (For keeping your greasy fingers off the steel- I use cotton) The process ..................................................................................................... Prep the steel: Before you begin to oxidize the steel, you must first remove all traces of paint, dirt, oil or coatings of any kind. Use acetone or alcohol to degrease the steel, and use your gloves when handling the object from this point on. The oils from your hands can cause an uneven corrosion, and fingerprints can even become permanently imprinted in the bluing process. *note* If you wish to preserve the edge on your blade and don't want it to rust, you can use fingernail polish to paint over the edge. Use a few coats, as a little of this may be removed in the boiling process. EDIT: since I made this tutorial I've had mixed experiences trying to preserve and protect the edges of several tools during this process. Sometimes the edge remains intact, much of the time the solution eats away any protective coating and leaves the edge vulnerable. If you choose to do a knife blade you should probably accept some degree of edge corrosion. With diligence and continual reapplication of the protective coating however you can keep the edge mostly intact, nothing you can't fix with a simple sharpening session. Its also important to note that as this solution bubbles and releases vapor, this vapor itself is highly corrosive and will also affect any bare metal not submerged in the liquid. Method 1- Browning the steel ------------ Step 1. In a steel pot carefully chosen, pour in enough peroxide that will fully cover the object to be worked. If rusting an axe, keep in mind that you will have to maneuver the head into a variety of positions to ensure even oxidation. Next, heat the peroxide over the burner to just under boiling temperature. A little under or a little over is no big deal; you just want the liquid hot, this part is no exact science. Once the peroxide is hot, start mixing in the salt. This may take a lot salt, just keep mixing it in until no more will dissolve into the liquid. You will know when enough is enough, as the salt will begin accumulating at the bottom of the pan. When this happens, the solution is ready. While the liquid is still hot, remove it from the burner and gently place in the steel with a pair of tongs. The peroxide/salt mixture will immediately begin reacting with the metal, and it will begin rusting right before your eyes. The length of time you need to leave it in depends on the steel, and on the size of the object being worked. Leave it in for just a minute at first, and then remove with the tongs and check to see how the rusting is coming along. It should look something like this: Once the steel is almost completely covered in rust, rinse it off under running water and dry thoroughly with a towel or napkin. Using a toothbrush, very gently start brushing away the loose rust; it should come off fairly easily. The goal here is to even out the layer of corrosion and make the surface smooth. This should result in a relatively uniform surface texture, though not all areas will be uniformly rusted at this stage. The finish may appear splotchy and uneven, and some areas may still appear to be bare metal; this is to be expected and is not a problem. We got some more work to do. Step 2. Step 2 is a repeat of Step 1. Now, place the object back in the peroxide bath for a second dip. If the peroxide/salt mixture is still hot, it can be used again for this second bath, and you can reheat it as necessary. Place in the object once again and let it begin to rust. This time it may react more slowly as the the solution becomes weaker. Of course you can always make up a new solution for each repeat cycle but I choose to reeuse for economy of materials. Continue the process from step one: Remove object from solution, rinse under water, dry, use toothbrush until surface is smooth and even. You should have a more uniform surface of rust this time. Continue this entire process until you have a nice, smooth, even layer that doesn't rub off. This make take a few cycles; it all depends on your steel and the size of the object. Once you are satisfied with the finish, you have successfully 'browned' your blade and can move on to the final step. Method 2--Bluing the steel ....................................................................................................... For this next step, you are basically going to boil your object in distilled water until the rust is converted into another type of oxide, and becomes black. In a pot (any will do, this step is perfectly safe and won't make trouble with the Misses by destroying her cookware ), pour in enough distilled water to cover the object to be blued. You will want to keep the object from touching the bottom of the pan, so you will have to rest it on something, or suspend it with wire or string. I like to simply put a few medium sized rocks or even a brick in the bottom of the pot, and place the object on top. Once it is set up, on a brick, or a collapsible steamer basket or whatever else, bring the water to a rolling boil and boil the object for about 10 minutes. Don't worry, the steel will only get as hot as the boiling water, and this will not affect the heat-treat in any manner. After about 10 minutes, depending on the size of the object, all, or most of the red rust should have turned black. You may have to flip the object into different positions during the boiling process so that the finish comes out even. This is what the steel looks like as it begins to change: After this process is repeated a few times, you should end up with a finish like this: Once this method is complete, you can go back to the peroxide oxidation process once again and repeat the entire process. This will build up several layers of oxidation and will ensure an even, sturdy coating. You can of course stop here; it all depends on the finish your trying to obtain. I like to rub the finished product down with a light coat of BLO. This is just a preference and is completely unnecessary for the final finish. Well, that's pretty much it. I welcome any questions or input on the methods described here. Hope this helps.