The inconel and the candy of the knife maker.
The knife maker’s candy is called inconel, and it is the “tight dress” for the knife when it goes into temper.
Now it’s not something you need but if you want to take the level and quality of the temper to the next level this is one way.
The aim is to create a dress at the knife trying to bring out all the air inside what is called “candy” in the jargon.
Also consider that there are “fine techniques” of performing the knife-tempering process called “candy”.
These blade seals are used to prevent carbon from being dispersed.
The candy consists of wrapping the knife inside an inconel material isolating it and helping to preserve the amount of carbon during the remediation phase.
The inconel is steel for tempra thick 0.05mm is an element that is often seen used by makers who perform the tempering themselves.
Two types are mainly used in the knife shop:
The 321 and 309 which are both valid but with a small difference in the maximum operating temperature.
The 309 is best suited for temperatures above 1050 degrees Celsius.
Personally, I sometimes take my knives to a specialized company that operates in the automotive sector that in addition to the hardening certifies me the hardness in HRC reached by each knife.
This is useful to make qualitative comparisons on the same knife, same material and see the quality level achieved.
Now Rockwell certification in HRC is fiery because it’s an objective value.
But when you use your temper oven or your friend’s, wrapping the blade in the hardening steel (candy) is essential because you have to harden the blade in the absence of oxygen.
The reason to make candy
The reason is because at high temperatures in the presence of oxygen the decarbura steel which means that it loses surface carbon forming small chamois.
Camolatures are deep enough holes that are difficult to remove, thus ruining the surface, and this carbon loss compromises the final properties of steel.
The sheets of steel to tempre
To avoid this you have to make candy with sheets to tempre or there are also compounds resistant to high temperatures made especially for these applications.
I have a friend who uses this technique a lot and has never had any problems, always if it applies with the necessary precautions but you have to do tests or have you explain.
How to make candy
Wrap the blade or blades in the inconel and before closing the package insert in the blanks (holes in the cod, blade curvature) of the combustible material (paper, cotton, cigarette filters).
Close the candy very well, re-cutting the edges with the hammer so that it is airtight.
With a wooden spatula, shape the inconel around the blade you inserted, sticking the blade well to minimize empty spasms.
Reached the temp. take the weather and take the time off, pull the candy out of the oven, cut the edge of the inconel quickly and dip the blade in the oil (possibly hot).
Keep in mind that sticking the inconel to the blade (with the wooden instrument), on the one hand helps to limit any decarbonation of steel, but on the other it makes it difficult to extract the blade from the candy.
For shutdown depends on what the steel requires or with tempering oil possibly hot 60 degrees C or even in the air but also this is a delicate but fundamental phase the container that must be wide to allow either the total horizontal or vertical immersion.
My advice is to do cold-bladed movement tests by switching from the cold oven to the container filled with water several times to understand the sensation (excluding heat).
If you do the shutdown with air you can also not extract the blade from the Inconel but it is a different type of shutdown /heat shock and depends on the type of steel.
If the inconel is very thin and very tight, you may dare to turn off the blade and candy together but I do not guarantee the good quality of the shutdown.
Ps. In the water I unconsiglo because the thermal shock too abrupt can create the twisting of the blade especially on some steels.
Pss. The landcoming is essential to do it at the right temperature that can be from 250 degrees C for about 1 hour and 1/2 and that you can do it using an oven from home but other steels require temperatures from 550 degrees C for about 1 hour and 1/2 and that therefore you have to use the temper oven or have 2.
Again there are several theory about making the find right away or that you can do even the day after that nothing changes.
Turning off in hot oil with candy
You can not dip the knife inside the candy to harden it but you always have to extract it, otherwise there are points of the steel sheet that adhere to the blade and others do not.
If you don’t, this creates a non-homogeneous cooling and you have a “spot” temper.
The resulting blade is all hardened but not evenly, so before soaking in oil/water/etc. you have to pull the blade out of the sealed candy.
She’s not a simple worker since you have a glowing piece in your hand.
Technique to extract the glowing knife from the candy
Safety (gloves, shoes/mask/apron/etc.) is important.
- With a clamp, pull the blade out of the oven.
- Take the scissors with your other hand and cut the inconel sheet at the bottom of the cod and open it for a few cm over the back of the cod.
- I support the scissors, and with the other pliers I phave the blade in the middle of the cod.
- With free tongs, remove the blade from the candy and immediately cool down.
- When you do the extraction pulls to extract but without making twisting movements otherwise you risk bending the blade.
- You have to do it in less than 10 seconds.
Where to find it
The alternative is the CONDURSAL Z1100
The CONDURSAL Z1100 is sold in 2.5 kg pots each and costs about 150 euros shipped.
- Bring the blade to the grain 400
- Grease the blade and apply the mixture with a brush (just a pass )
- You dry it well (even with a hair dryer to do first) and put it in the oven!
if you put it in a hot oven at 600 degrees you will see that when you turn off part of the product crumbles and the rest or takes it off by boiling water or with a sandpaper bottle always 400… maybe with a little svitol.
- When the first pass the paper kneads a little because it melts the product
Personally I prefer candy, I use it when they are knives to make fast and cheap and I feel good but my choice is the inconel.
Attention! it degreases the knife very well and if when you apply it it will give you a “shock” effect is not good.
The hardening phase is key and testing to find the best way is important.
Consider that a wrong temper and throw the knife.
Consider that you need to check the HRC hardness values of the steel table.
It is a science but that with the means available today even in your laboratory you can reach high levels of temper.
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