Case hardening is also not easy to do. It involves packing the item in a sealed container which is filled with some kind of carbon source, and putting it in a furnace and heated at high temperature (I believe you want it glowing cherry red) for hours. Idea is to get the extra carbon to diffuse into the metal.
In the trades “mild steel” refer to 1018 steel, the 18 refers to their carbon content which is around 0.18%. These are used for construction, not knives. With knives you want very high carbon content. They use them in construction because they can be easily welded, and is fairly cheap. High carbon steel is going to be in excess of 0.80% to 0.95% (you don’t want to go much higher than this, it will result in brittle iron instead).
Or if you have a TIG welder you can take a piece of low carbon steel and simply hard face the edge by using high carbon steel filler wire.
And if you’d said that originally, I wouldn’t have complained.
Perhaps you can try to identify the difference between that statement, which looks broadly true, and “mild steel is low carbon steel, with less than 0.18% of carbon in the steel”, which isn’t (moreover, it isn’t even true for 1018 steel, where as you say the carbon content is 0.18% as specified in the name).
Or the difference between “difficult to weld” and “cannot be welded under any circumstance”, or between “soft” and “soft as butter”, or between “difficult to harden” and “will never, ever harden no matter what”.
The point is, you don’t need to exaggerate and embellish every single thing, and you don’t need to write all the time outside of things you know. Nobody asked you what the carbon content of mild steel/low-carbon steel is, and with a few exceptions I doubt many on Forumosa know or care.
It’s totally fine not to know what the carbon content of mild steel/low-carbon steel is, but if you’re going to bring it up you could try to get it right. Otherwise, no need to mention it. Just… is it that difficult to not write about every topic so carelessly? If you do that, you’ll get fewer people complaining at you.
I’m sure I’ve said this before, but an important feature of “facts” is that they’re factual.
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You’re not providing “facts”, you’re insisting on “facts” which are clearly untrue and will potentially lead to problems for anyone who believes them.
You’re even contradicting yourself. High carbon steel can and is regulalry welded by industries requiring it. It’s not “cannot be welded under any circumstance” or “theoretically be welded”, it can and is welded.
It can and is welded, have welded many a fire grate in my youth.
Or other methods, cold rolling for one.
LOL, are you “in the trades”? Mild steel is not only 1018, look it up.
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Back on topic.
@d1234 ,
Keep the creativity, but pick up a little black book, like a moleskin format. Every stationery store in Taiwan will have something, often with graph paper.
Every 3 pages gets an idea. Flowers in a knife handle? Flowers in the blade? Put that on page 3. (1&2 for your exhaustive table of contents)
Group all your craziest stuff on one page, then when you have time, or learn something in school that informs a given idea, give it a page. Kicking the tires of one idea often leads to a few others cropping up.
Do well in your engineering classes. If the school has an art department, poke your head around there. You might find a similar disinterest in your flower idea, as they may be distracted by ‘serious’ art questions, just as your professors are distracted by ‘serious’ science.
Art and Science inflect into each other, once in a while. Materials science as a field is where this inflection occurs, perhaps most frequently.
Still, make friends with a few ceramists, if you can find any. Google metal and glass art exhibitions, and find those people. You’re bound to be intrigued by some of their work, enough to ask how they did it, but you may also be in the place that both science and art like the most - asking the question : “what if you…?”
Fairly quickly, your new artists friends will ask you : " how do you…?" “can I…?” “Do you know anything about…?” They’ll ask questions you never imagined, and many may be impossible. Your service to the world will be to determine how or why they’re impossible, or if an alternative to the same (or better) effect exists.
Study early, study often, finals are around the corner!
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I’ve heard about people welding cast iron, but the problem is what welds fine this time may not weld at all next time, insisting on cracking anytime you get a bead on it. Point is there’s a huge amount of variability in cast iron, and it’s like a box of chocolate. A lot of cast iron is scrap metal thrown into a furnace. I believe they use nickel rods to weld it, but even then success is often not guaranteed. Simply better to braze it with silicon bronze.
How many times have you welded cast iron?
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I have not tried. If I have broken cast iron items I will most likely silicon bronze braze it.
YouTube. Seriously; making knives has been super trendy and there are tons of good videos on it. Don’t go crazy thinking you need to forge this for your first one; just get a blank, shape it, heat treat, and sharpen.
Ha, yea, because DIY knife making is a practical application that most people should know.
Almost like that’s what you responded to with “will never, ever harden no matter what.”
there’s different ways.
So… how much depth do you need for a knife edge? 
This thing seems more like an experiment then something he’s really planning on getting into, so seems like a case hardened single beveled knife might be totally reasonable.
OP, if you want to do this with mild steel, see if you can get a hold of some kasenite (not available in the US anymore, don’t know about elsewhere) or cherry red (or some other hardening powder). Or, as TL suggests, just get some tool steel. No need to overcomplicate this if you just want to play with this, and no need to get hung up on the steel or hardness if you just want to experiment with it. If it’s fun,.worry about that on your 2nd or 8th one.
Ha. Most tradesmen aren’t going to be referring to any particular alloy, and there’s tons of different mild steels.
or, not.
You’re using some seriously absolute terms. Then heaping superlatives on it to reinforce the point.
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FB has lots of groups. If you just want to grind steel and make a knife and handle or if you want to make a mini foundry/forge for heat treating or even smithing…quite a few groups.
I was looking at these on YT a while back.
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I seen those light, foamy refractory things used in forges, ovens and such, what are those called? I got no idea where to get those in Taiwan. All I seen are fire bricks, but nothing like what I seen on youtube.
They feel like styrofoam, yet they can resist very high temperature.
What are they called in Chinese?
Ask a Taiwanese person? Or maybe google?
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Some kind of wool which is then coated but I’m not sure you really necessary need it unless you are getting more serious. Anyway this is one of the fibers
I’m sure the material exists but there’s not really a “refractory material supply store” in Taiwan to pick those up, and the tiny market means online vendors won’t really have it (as the number of people in Taiwan who’s interested in making knives is likely very small).
But I’m interested in finding good refractory material that’s easy to cut into shape to fit into metal cans. I’ve found fire bricks online but got rid of it when I moved house. A few stacked would work well for heat treating small items but aren’t convenient to use and are a bit heavy. That Kaowool stuff looks really good for stuffing a tin can to make a mini forge out of.
It isn’t always obvious to google and find it. Believe it or not Taobao is a really good source of “stuff” but the challenge is finding out what they are called in Chinese. Calling it by the wrong name means not finding it.
Edit:
Really not that complicated TL. I’ve done it numerous times and I can’t read Chinese. You’re Taiwanese and can.
Possible options:
- Google it until you find the correct term for what you’re looking for.
- Stick it into Google Translate to get an approximate term, then type that into Shopee/Taobao/whatever. There should be enough key characters in the approximate term to lead you to the standard/preferred term, then use that in a subsequent search.
- Ask ChatGPT for some search terms and repeat the above, even though you think ChatGPT is an unreliable source of information.
- Don’t build a forge in your bedroom.
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I just edited it, and I did find it on Taobao.
There is one that’s good up to 1200C and another one that is good up to 1400C (it is more expensive).
The 1200C one appears to be Kaowool, or has similar heat properties as Kaowool. Obviously not going to get the aluminum foil lined ones.
If I want to forge knives, I’ll look into it. It isn’t that expensive either, at about 25RMB per meter for a 5cm x 65 x 100 cm sized piece, while the higher temp version is more, at 65 RMB.
Anyways OP give it a thought if you want it, you can heat the forge using those 300nt BBQ torch. I’ve heat treated a few machined parts this way.
Let me know if you want to build one and maybe we can split an order, because I don’t think I need more than a meter of the stuff, if using a 3kg tin can as a forge body.
I can’t post Taobao link because you can’t follow it unless you have a Taobao account.
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Just Google what you are looking for in English and add Shopee on the end. Images of it usually show up in Chinese from shopee then click and see more products and the name.
Try out…forging supplies shopee
The problem with that is that Malaysia, the Philippines, and Singapore have Shopee too and are more likely to have English in the ads. That’s what just happened for me with your search term (nothing at all from Shopee Taiwan comes up, at least in the first few dozen results). Might work okay with a model number or something non-English.
The image search function of Shopee isn’t too bad though, IME.