Sunday, February 20, 2011

Mark's new Forge

Hello blog fans.  Unfortunately for you, you have a guest author today.  Since this post is about my new forge, Whit thought it would be best for me to write about it.

A little background on this project... 
I got interested in building a forge after meeting my friend Ryan Minchew of Minchew Knives and seeing his forge (click the link, this guy's knives are amazing).  I believe he uses his for heat treating some of his awesome knives as well as making damascus steel.  Anyway, after I returned from my field assignment in Texas, I took a look at my (tiny) garage and realized that the space was underutilized due to being overstuffed with power tools.  I had so many power tools in there that i had to pull out the table saw to use the drill press or the band saw.  This simple task kept me from many nights in the garage.  I decided that hand tools were the way to go.  Less space, less setup time, more workout.  I need the exercise... 

At the same time I started to realize that the biggest roadblock keeping me from pursuing more projects was moolah.  The cost of nice hand tools and hardwood (another post on wood coming soon to a blog near you) was keeping me from doing much of what I wanted to do.  An idea started to form in my head that would allow me to process scrap tool steel (leaf springs, coil springs, axles, old files, etc) and scrap wood (think brushpiles) into usable tools and lumber.  I sold off all my power tools on craigslist and used the money to build the forge you see below and to purchase a chainsaw and chainsaw mill.  

After much reading, I began gathering materials.  The basic idea for my forge comes from a forge I saw over at Zoeller Forge , where I later purchased my insulation, fire brick, and burner regulator.  Anyway, enough words.  more pictures.

I started with an old freon tank.

"this is how it will look honey!"

First burner test.  My burner is an atmospheric propane burner very similar to the Ron Reil burner.  The difference is that I used a Tweco 14T .030 GMAW contact tip as my gas orifice.  This makes the orifice replaceable if I ever decide I need more or less gas flow...therefore, more or less heat.  

First burner test

I just like this picture.  

When freon is burned, it makes phosgene gas (a nerve gas).  since I had to do some welding on my tank, I wanted to be sure all residual freon was removed.   My solution was to burn out the tank for 20 minutes or so in a safe environment (read -when I'm not leaning over the tank with an acetylene torch).  I'm not sure how hot the thing got, but it was hot enough to take some temper colors on the outside of the shell....also note the melted snow on the ground around it.  I wound up not needing the fan since it was a windy day.

After burning out the freon, I made a trip to my grandpa's where I welded in the burner tube (I won't show you the weld, it's ugly).  I painted the forge body with a can of spray grill paint, then insulated it with some 2300F ceramic fiber blanket.  I also bedded a 3000F firebrick in the bottom of the forge, then coated all interior surfaces with pilstix 900, a high emissivity coating.

My first heat was mid-day out in front of my house, trying to anneal some old files.  the daylight doesn't show the color of the metal or refractory very well.

After my first heat, I noted how "cold" the 3 inches nearest the door opening were, so I added a ceramic fiber blanket curtain in the door way.  This gives me a radiating plane to radiate the heat back into the forge.

My first heat, trying to anneal old files was unsuccessful.  I subsequently learned that I didn't hold the temperature long enough.  I was able to make and harden an easy out to remove some twisted off bolts from another project.

Here you can see the smaller opening allowed by the curtain.  Much hotter in there.  The rest of the photos were taken after dark, which shows the colors much better.  You can't see in this photo, but I also checked temperature with my thermocouple and multimeter this time.

My second attempt at annealing...  I held the temperature at around 1600F for an hour for one batch and 30 minutes for another.  I want to compare results.

Taking a file out of the forge after 1 hour at temperature

Posing for a picture

I shoved the hot steel into an old 5 gallon paint bucket full of cat litter to help the steel cool very slowly.  I may or may not have burned a hole in the side of the bucket trying to force an old lawnmower blade into the cat litter....maybe I'll be a bit more gentle in the future...

Now I just wait for them to cool overnight.  Hopefully it's more successful this time around!



  1. Dear Mark,
    I am going to pretend that I understand every word you just wrote. Every. Word. And in light of my understanding of every word, I am impressed. Even if I don't know what I'm impressed with.

    Dear Whit,
    You should put a "Warning: small brains may combust" disclaimer on posts like this.

    =D You two are awesome. Just saying.

  2. LOL I love your comment, Brit. It's okay... I don't understand most of what he says either. I just look at the pictures and say, "ooooh" and "ahhh" and "wow babe, that's really cool!" ...which it is... I just don't understand all the official language. lol =D


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