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Brandonk42

Question on heating metal

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Hello all!

First off great site and great contributors! I've learned a lot and I am very anxious to learn more.

My question is about the time it should take to heat metal. I just built a 55 gallon drum forge using the plans on this site. I am wondering if I was successful. About how long should it take to heat metal to the correct temp? I was testing it out on a railroad spike I had laying around and it seemed to take quite awhile. I was using coal and coke as it is abundant in this area. My air source was a hair dryer. I have a feeling I may have put the metal in before the fire was hot enough in my excitement.

Any tips as well would be greatly appreciated as I'm definitely very much the rookie.

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The color of your fire ie red, orange, yellow,up to white; will be as hot as your metal gets .
I hope this helps!

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Once you get the coal burning, wait till you get a good solid clump of orange coals. They will stick together as they coke so take your fire rake and break it up. You simply need a good bed of coals equal to or larger than the piece you plan to heat. Your fire is ready to use when most of the smoke stops and you have a bed of coals. Have you ever grilled hamburgers using charcoal? It's the same principle. Best of luck!!!!

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This question is sort of like "how fast will my car go?" without giving us any information but that it's a ford and runs on regular unleaded.

If the coal is gooey and smoking it is not ready for metal yet.

Note always save some coke from your last fire so you can start *fast* with your next fire with the old coke core ready to use while the new coal is coking along the perimeter. One sign of a newbie is they want to burn the fire all the way down at quitting time leaving them nothing to start with the next time and so making start up *very* slow.

The first heat is the longest as the steel has to go from ambient to forging hot. The following heats the piece should still be around 800-900 degF when it goes into the fire and so re-heats a lot faster.

Knifemaking alloys are often sensitive to sulfur in the coal and so should be only heated in well coked fires---I tend to have a "lower grade" project like pointing tent stakes to do while a new fire is burning itself clean before working on a blade.

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Thank you everyone for all the useful information! That's why I love this site. I hope I can pay it forward one day.

I'm going to use this information and give it a go again in the morning. It seems I put the metal in before the forge was heated up properly and didn't have a nice bed of coals on the bottom like the one poster mentioned. It did heat the metal but it took a real long time.

Good tips on the fire color and also on how deep to make it as well.

Thanks again!

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welcome to ifi!

before you heat your metal, make sure that the fire is glowing orange to white. railroad spikes are sort of thick compared to the stock that a lot of beginners work with. It should take a few minutes to get it up to heat at first but once you heat it up, it'll be faster to reheat (unless you cool it down completely).

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As for "paying it forward" nothing is better for everybody's education than a good question. I learned more from the two regularish students I showed the basics than all the reading and practicing I'd done till then. Answering questions like, "WHY did you do THAT?" makes you think about it so you can explain it. I'd been doing things by feel and experience so long there were quite a few processes I used but had no clue as to why except they worked.

Fire management is one of the most important aspects of smithing and there's a lot of experience based "feel" to getting it right. Getting the fire right depends a lot on fuel, fire shape, blast type and source. For example a side blast works differently than a bottom blast forge and you need different senses to manage them. Don't worry, it's not magic and far from secret brotherhood stuff.

Probably the easiest way I can say it is, Make the heart of your fire (right) the color you want to work your steel. Once the fire's right, iinsert your stock and be patient. Then when your stock is the same color as the fire and has been for a minute it's ready for some forging. Now for a detail, cold steel will come to temp on the outside before the center is to temp so you need to let it soak. Soaking means letting the heat soak into the center and time depends on the thickness of the steel and I'm sure someone will post the general times, I don't recall. Detail two being, REheating steel takes less time as the center will cool more slowly than the outside so it'll take less soaking.

Here's a last (for now) tip. You can learn to judge steel's forgability/working temp by ear, heck feel. Listen closely as you learn and you'll discover the different sounds steel makes as it cools. In general yellow steel sounds soft when you drop it on the anvil or hit it with the hammer, like (REALLY) stiff modeling clay. then it'll start thunking then you'll start hearing a tinky quality to the thunk, this means you're getting close to dropping below good working temp. If it starts clinking or WORSE ringing it's below working temp stick it back in the fire.

On that note carefully note how it feels in your tong hand and how the hammer reacts. After a while you'll note the differences between stricking hot steel and cooling.

Believe it or not eyeball judging the work's temp (color) is close to the bottom of the indicaters I use. On the ANVIL the old mark one eyeball is the only thing I use in the fire.

The best and fastest way to learn all these tricks is to find the local club, a local smith, etc. you'll learn more in a few hours under instruction or just watching first hand than in weeks of teaching yourself. And yeah, I taught myself for a loooong time and learned more faster and better the first time I worked with someone else. I ALWAYS learn something watching someone else at the forge, even if it's DON'T do THAT!!!!:o

Frosty the Lucky.

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Bumping this to once again thank everyone! With all your advise I got my forge working wonderfully! Definitely was hot enough. I wasn't leaving enough coals on the bottom in my initial attempt and it was taking so long to heat that I thought I was doing something wrong. (Of course I was) After reading your posts I actually was surprised at how much faster the metal got to working temp. In fact it surprised me it worked so quickly that I melted a piece on the first spike I put in there. Learned something right there as well.

I made my first knife today and although it's not close to perfect it was a great practice run in which I learned a lot from the hands on aspect. And man am I loving it!

Thanks everyone and happy forging!

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Glad to hear it Brandon! There are few things in life so fine to play with as a good fire. Beating an innocent piece of steel into submission is close but FIRE . . . Mmmmmmmm, good.;)

What are you working for the knife? Don't sweat even trying to get it "perfect", that's what grinders are for. Whatcha grinding with? If you don't have a decent belt grinder you might consider a scraper. Hand scraping isn't as hard nor time consuming as you might think. I can't remember what the Japanese scrapers are called and I'm blaming the TREE! Gotta LOVE a good excuse.B) Oh wait, just as I was ready to hit "Post" it came to me, they're called Sen.

I think, If I'm wrong it's the TREE, I'm blaming the darn TREE!

Frosty the Lucky

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The scraper is called a Sen. I made one but dont believe i have the correct bevel. Should the scraper be pretty blunt as opposed to an acute knife like angle?

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The scraper is called a Sen. I made one but dont believe i have the correct bevel. Should the scraper be pretty blunt as opposed to an acute knife like angle?


Yes. Edge angles of something like 70-85 degrees seem to be common. Some people make them a sharper than that, but think lathe bit, or at most drawknife, rather than regular knife blade.

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Think a short draw knife with a more obtuse bevel. The only one I've gotten to play with you slid on the flat and let the edge take off the high spots. It was amazingly fast, faster than I was using my belt grinder. The angle is for relief so there's room for the cuttings, the bevel lifts them from the parent stock and more importantly breaks the cuttings into chips rather than curls. A more acute bevel would tend to dig in and mark the stock.

Frosty the Lucky

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I have never used a sen. Would you scrape with it before hardening or afterward? Before hardening seems most viable to me. I guess that you'd need pretty high carbon steel for such a scraper... would 1095 work okay? Do you turn the edge like a card scraper? Do you leave them full hard? Or temper them to what color? I am guessing that you'd harden only the edge rather than the whole tool?

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I don't know much about Sen other than that they work well.

I would assume you'd use them for general shaping before heat treat. The edge isn't rolled, it's functionally the same as a wood chisel, not a scraper. The edge being obtuse is robust so it may not need tempering but I don't know. The one I used and those I've seen weren't very deep though they were around 3/8" thick and not long, 3" or so maybe. It makes me think hardening the whole thing wouldn't hurt a thing, even if you tend to drop stuff. I think 1095 would be good, worth a try for sure.

One last time, I'm mostly making guesstimates as I don't actually know much about Sen. I suggest NOT basing anything important on what I say about the things. Maybe as a departure point for experimenting but . . . :blink:

Frosty the Lucky

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