Using Our Billets
Firstly, thanks for using our steel! We really appreciate the support and hope you will enjoy using our billets. Please tag us in social media posts, we always love seeing what you create.
Here are some techniques and order of operations to get good results with our billets. We assume everyone using these billets will have made at least a couple of knives before, so this guide will be focused on working with san-mai and pattern welded steel, with some extra tips to get the best results. Any feedback is appreciated.
Straightening:
Straightening is important as you can’t grind san-mai straight or the pattern will be uneven. Don’t let this put you off though, these billets are easy to work with.
Our billets come annealed and ready for grinding, they are usually pretty straight however some may need a slight adjustment. Straightening can be done during heat treatment while the blade is hot, or by hammering over a soft surface while the steel is annealed. Keep this to a minimum as it can induce stress in the steel. If you have any issues please feel free to email us.
Post heat treat straightening can be done by a number of methods, stick to what you know. Personally, I like to heat treat with a partial quench and finish between aluminium plates, this keeps them straight, but further adjustments can be made if necessary. One method is to bend it a little past straight and heat carefully until you feel the tension release. Don’t over do it, it’s easy to bend more if needed. Cooling with water on one side can add or take a little bit of bend as well. If the blade is pretty straight I recommend starting your bevels first to relieve a some stress in the steel and to make sure you don’t over heat the edge. A carbide hammer to peen one side can also work very well. Do not grind a bent san-mai blade straight.
Heat treat:
We offer a heat treat service, please contact us if needed. Heat treat with other companies at your own risk.
Heat treat will be unique to the steel type used so I will include instructions in the listings for the billets, all I will say is that a thick coat of oil on carbon steel cladded billets, before they go in the kiln will help prevent and partially reverse decarb. Beveling at 45 degrees all the way round can also reduce the risk of cracking the core. This usually only happens with billets made from different materials, for example stainless or wrought iron over carbon steel.
Bevelling:
I like to do all my bevels post-heat treat, this makes straightening easier and ensures your bevels are decarb free, which is important for a smooth dark etch. I would highly recommend using an old 80 grit to grind in 45-60 degree bevels before going with a fresh 36 grit. This will increase the life of your coarse belts and give you some rough guidelines for centering the edge. The exact center will be found through grinding symmetrically using the nickel lines as a guide. Go slow, keep checking your edge thickness and look down the blade to make sure stays straight. Occasionally you can see the blade bend as you’re grinding, this is more common in billets with a softer outer cladding like wrought iron or stainless steel. Switching sides often will help. Be careful not to remove too much material from any areas that may have warped towards the belt. I like to grind to 3/4 bevel height and to where the nickel is just visible along the whole blade on both sides, then start to neaten everything up with an 80 grit belt, checking it over thoroughly before moving to finer belts. Changing the angle your blade is on the platen at will help give you a flatter surface. Grinding vertically will help you get the most consistent edge and pattern and with a waterfall platen, you can neaten up your plunge lines as well. For kitchen knives, I like to grind the edge down to around 0.2-0.4mm depending on desired durability, and then convex to sharp.
Finishing:
Again, stick to what you know. There are so many ways to finish out these billets, you really have to figure out what works for you. I take mine to 320 grit on the belt sander, this gives a good level of flatness for hand sanding. If done well you can start hand sanding at 1000 grit however most likely you will need to work up the grits to properly smooth out the surface and remove all rougher scratches. I would recommend starting at 320/400 and taking it up to 1000. Rhinowet paper is the best I’ve found for this. Some people prefer stones, just stay away from cheap silicone carbide paper. If it is neat, a 400 grit satin finish can look very nice and save some time, it's all personal preference. Cleaning and de-greasing is a very important step with etching, it can take a bit of practice and there is plenty of info elsewhere online so I am not going to explain it here. Warm water and dish soap works well. Check after a very short etch to make sure you didn't miss any areas. Every carbon steel blade needs a bit of protection, we highly recommend our leather-and-knife-balm. It's a carnauba wax based product that lasts longer than oil and doesn't leave any streaky marks visible in photos.
Dark-Mai:
I can’t give away the details for our ‘special black’ finish but you can get close with repeated polishing and etching with coffee. Most of our etching is done in ferric chloride. I personally love the look of etching in ferric and then buffing off the oxides to a smooth satin grey colour which contrasts the polished nickel line nicely. If you want a dark black finish, try a few repeats of etching and cleaning off with fine wire wool, and when it comes out the ferric for the third time, neutralize and dry with compressed air without touching. This will let the oxides ‘set’ and become more durable. Add a bit of wd40, and let sit overnight.
Stainless clad:
The stainless san-mai can be finished in the same way as the dark san-mai. Finer surface finishes and polishing post etch may decrease the carbon migration colours. This may be a good thing, or you may want to bring it back with another etch. I like a couple of etching and polishing cycles followed by an orange juice etch. Clean off and oil without touching.
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