I just heat treated a 1080 blade in my gas forge and I didn't realize that my thermocouple placement in the forge was wrong and registering 600 C when it was actually maxed out (1000C) for who knows how long. This was only the second knife I had done so I was a little slow to pick up on things. The knife was glowing orange for quite a while (two minutes?!?!). I dont know how hot the blade got but it was definitely over 1500 C. How much wiggle room do I have in temp and how bad could the blade be now after over heating it? Is there a way to tell? I washed the oil off before tempering it and it was weird that some of the black rubbed off...but that was on the handle where it sits on the fire bricks in the forge (forge is too small and I don't have the tools to hold on to the blade while it is heating up.
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How hot is too hot (when heat treating)
- Thread starter dzlvs8
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Consolidate your threads. You could have asked the other questions in this one too.
The answers to all those questions are in the stickies as well. Suppliers, HT info, etc etc etc.
Cheers.
The answers to all those questions are in the stickies as well. Suppliers, HT info, etc etc etc.
Cheers.
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For one I doubt it got over 1500C, that would be way above welding heat and you would have probably scene sparklers comiing off of it. If that is the case its toast. If it just got into the orange or yellows then you can do some normalizing and grain refinement and redo the heat treat.
In a forge unless its a PID controlled one you still need to watch colors and keep a close eye on it. I generally like to do my HT at night so I can see without a doubt the shade changes in the blade and to ensure uniformity.
Do you have a muffler? It would probably help if you dont have one to try one out.
In a forge unless its a PID controlled one you still need to watch colors and keep a close eye on it. I generally like to do my HT at night so I can see without a doubt the shade changes in the blade and to ensure uniformity.
Do you have a muffler? It would probably help if you dont have one to try one out.
Nearly every answer ever needed about knife making is in the stickies. Since people shouldn't ask questions that have answers contained in the stickies, then there really shouldn't even be a Q&A section. I've read a lot of the stickies a while ago. There are multiple stickies on the same topic. Each write up can be pages and pages and pages and pages long. Others dont have the info I am looking for. There can be a point to having too much info and that is the case with these stickies. However, they are an amazing wealth of knowledge. It takes a very long time of rereading stuff i already have read only to find out my answer isn't contained in the particular stickies that I read on the topic. If I cant find it quickly, I head to the Q&A's.
I ground my knives MONTHS ago and casually researched the stickies and youtube videos over the past months to acquire my knowledge on what to do next. I can't remember every detail that wasn't crucial at the moment (things like overtemping a knife), thus, the Q&A's.
I made separate posts because equipment finding and over heating a knife is two separate topics. I fell the thread discussion would be a mess if I consolidated them.
Quint:
My gas forge gets up to 1000C in about a minute, I cant read temps after that but I assume it gets a lot hotter fairly quickly. Anyway, it was orange for a long time. It never turned yellowish. So I am going to assume it is ok?!?! I did not see sparkles, my knife was orange and became at least a shade or two (or more) brighter, and the knife was not magnetic anymore. Thanks for the info
Another question. I want some cheese sticks. Is it safe to make cheese sticks in the oven while tempering a knife or is there some sort of chemical release from the knife that happens during this process? I know that isn't in the stickies.
I ground my knives MONTHS ago and casually researched the stickies and youtube videos over the past months to acquire my knowledge on what to do next. I can't remember every detail that wasn't crucial at the moment (things like overtemping a knife), thus, the Q&A's.
I made separate posts because equipment finding and over heating a knife is two separate topics. I fell the thread discussion would be a mess if I consolidated them.
Quint:
My gas forge gets up to 1000C in about a minute, I cant read temps after that but I assume it gets a lot hotter fairly quickly. Anyway, it was orange for a long time. It never turned yellowish. So I am going to assume it is ok?!?! I did not see sparkles, my knife was orange and became at least a shade or two (or more) brighter, and the knife was not magnetic anymore. Thanks for the info
Another question. I want some cheese sticks. Is it safe to make cheese sticks in the oven while tempering a knife or is there some sort of chemical release from the knife that happens during this process? I know that isn't in the stickies.
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I have made fish sticks while snap tempering. I am not dead ...................yet.
I agree. I am having a hard time finding a good tool for cheap. The best I have found so far is a $35 temp readout and k thermocouple on ebay but that only goes to 1300C. I know there have to be better options out there, but its hard to search temp readouts by max temp!
You probably got the blade @ 1800 degrees Fahrenheit, @ 1000 C. Based on what most smiths have said you probably have some grain growth, but 2 minutes isn't a long time. You can re heat treat the blade to reduce the grain size and quench from just above non magnetic (bright red).
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Ok the cheese stick thing is pretty ridiculous and probably wont help you get any more of your questions answered. There is a ton of information in the stickies to get you doing the right thing and not setting your self up for a knife hitting 2000F by lack of setup or attention.
Plus if you try doing a search using this https://www.google.com/cse/home?cx=011197018607028182644:qfobr3dlcra you will get better answers then using the search button here on the forums.
Check out auber instruments (which is in the stickies I might add) and get one of these
http://www.auberins.com/index.php?main_page=product_info&cPath=20_3&products_id=39
and
http://www.auberins.com/index.php?main_page=product_info&cPath=20_3&products_id=40
Then get one of these to hook it up to or something similar
http://www.auberins.com/index.php?main_page=product_info&cPath=1&products_id=237
You have not posted pics of your forge or whatever it is your using. May get alot of help with a pic of your contraption.
Plus if you try doing a search using this https://www.google.com/cse/home?cx=011197018607028182644:qfobr3dlcra you will get better answers then using the search button here on the forums.
Check out auber instruments (which is in the stickies I might add) and get one of these
http://www.auberins.com/index.php?main_page=product_info&cPath=20_3&products_id=39
and
http://www.auberins.com/index.php?main_page=product_info&cPath=20_3&products_id=40
Then get one of these to hook it up to or something similar
http://www.auberins.com/index.php?main_page=product_info&cPath=1&products_id=237
You have not posted pics of your forge or whatever it is your using. May get alot of help with a pic of your contraption.
It's odd. Some people suggest thermocouples, but they dont tell you the temp of anything but the forge. So judging the temp of the blade is still a craps shoot of looking at the color or using a magnet. I have an idea though. How about taking a piece of scrap bar stock that is thicker than the blade, drilling a hole in the side wall of the stock, sticking the thermocouple in and leaving it there. I would think that that would give me a way way way more accurate reading that would be closer to what the knifes actual temp would be.
I'm surprised that with all the experts out there, the only way they are judging when there knife is up to temp with out a PID controller is by color or by a magnet.
I'm surprised that with all the experts out there, the only way they are judging when there knife is up to temp with out a PID controller is by color or by a magnet.
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That wouldnt tell you the temp of the blade your working on either. If you know the temperature of the space the steel is in then letting the steel sit in that space for a certain amount of time will give you the temp of the steel. Thicker the steel longer its gotta hang out to equilize. Same thing is going to have to happen with the piece of steel you put a thermocouple in but if that steel is any different in size or geometry of the blade its not going to be accurate until some given time of soaking at that temp.
Also if you did that and used it as the input to a pid controlled forge then I would imagine you would get huge overshoots and undershoots, the forge would be blasting trying to get up to temp until the metal got to the determined temperature then it would slack off while the steel had to cool down a bit. This wouldnt be good for the blade which is at a different geometry and cooling and heating at different rates.
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Look, I'm no expert by any means. So please understand I'm not making assertions as if I'm God's gift to knifemaking or metallurgy. HOWEVER, this is what I did.
Your forge, kiln, whatever, use a thermocouple that gives consistent readings. The closer you can get it to the actual blade you're working on, the better. Get yourself a piece of 1095. Soak at critical for a few minutes, then quench (highly recommend using quenchant designed for the steel, not motor oil, or anything else. This is evidence based. Grain structure on knives I've made with both canola and motor oil mixes are more coarse than the likes of Parks 50. If you can't find parks, pm me and I can get you in touch with someone reputable). After quench, check with a file. Soft spots? Not hot enough. Bump your temp 10 degrees and try again. Do this until you get uniform results with the steel. No soft spots, etc. Now you can have a relatively close idea of what the variance in temp is from thermocouple to actual steel. So, lets say your thermo says 1516F when you achieve proper HT on 1095, and you know austentizing temp is 1475F, you know you have a variance of roughly 41F. Write it down, then try it with other steels. HT 5160 at 1566 (reading on your thermo/41 degrees higher than actual temp) and tweak your holdovers accordingly.
Your forge, kiln, whatever, use a thermocouple that gives consistent readings. The closer you can get it to the actual blade you're working on, the better. Get yourself a piece of 1095. Soak at critical for a few minutes, then quench (highly recommend using quenchant designed for the steel, not motor oil, or anything else. This is evidence based. Grain structure on knives I've made with both canola and motor oil mixes are more coarse than the likes of Parks 50. If you can't find parks, pm me and I can get you in touch with someone reputable). After quench, check with a file. Soft spots? Not hot enough. Bump your temp 10 degrees and try again. Do this until you get uniform results with the steel. No soft spots, etc. Now you can have a relatively close idea of what the variance in temp is from thermocouple to actual steel. So, lets say your thermo says 1516F when you achieve proper HT on 1095, and you know austentizing temp is 1475F, you know you have a variance of roughly 41F. Write it down, then try it with other steels. HT 5160 at 1566 (reading on your thermo/41 degrees higher than actual temp) and tweak your holdovers accordingly.