Hello

I am new to this forum and new to Blacksmithing so any advice is much appreciated.  I have been working with a 2 burner gas forge for a while and decided it was time to build my own coal forge.  I was planning on using a disk harrow blade as my fire box but after doing some more reading I am beginning to think it may be too shallow.   I am including some pictures of the forge being built and would welcome any input. 

Thanks in advance.  

Well, the old rivet forges didn't Evan have a fire pot. You don't need one either just build it up with some fire bricks on the other side and mound up the coal more.

                                                       Littleblacksmith 

Would it be better to use fire bricks or weld a rim on the back side of the disk?  I have plenty of steel.  I could do a 3 or 4 inch rim on the back side.  

Even a small disk is to big for a pot, and to shallow. Now that said, if you let ash accumulate and use a bullet grate you can make it work. Laying a layer of 2" brick on the whole table would work to get you to a workable deapth. When one sees a forge full of coal, what one doesn't see is the sand, ash or dirt underneath taking up space and forming the "fire pot".

now a note on brick, coal clinker sticks to vitrified clay like glue, so just use it to form a table and take up space.  

I still have the steel that was cut out to accommodate the disk. I could weld that back in and re cut a hole to fit a normal pot.  Would that be a better way to go?  And then use the firebrick as you suggest?  

A simple bullet grate is a 2" pipe cap with a 3/4" hole drilled in the center. Why a bullet grate you might ask? The clinker slides off and forms a donut shaped pool around it instead of ontop of your air holes. 

Small coal fires are relitivly shallow (a 6" fire ball needs only 3-4" from the bottom blast tuyere to the table) wile bigger fires need more depth. 

I think it would, one of the best, simplest I have seen was a 6" to 2" reducer bell, with a rim welded to it to keep it from falling threw the plate, then make an "S" out of 1/2 square for a grate. Gives you a small manageable fire (about 6" is all you can work by hand anyway), as I play with charcoal as well as coal I prefer a side blast, but to each their own. 

I don't have a 2" cap handy but I do have a 2" union that I can weld a plate on to make a cap.  

Thanks for the advice.

 

Welcome aboard Chris, glad to have you.

My big hardly ever used coal forge is a flat steel table 14 ga. I believe 3' x 4' with a 2" x 2" angle iron rim flange up. I won't go farther into it's construction other than to say you don't need plate for the bed, even under the fire. My tuyere is exhaust tubing, the vertical section is 4" big truck pipe with 2" horizontal for the air supply. The ash dump is an exhaust flap cap clamped to the bottom upside down. I welded a flange to the top end where it connects to the table. The table has a 3" dia hole drilled in it for the air. (I have lots of hole saws, wonderful tools they are.) My original design was a bunch of holes in the deck for the air grate and that worked for a couple hours before burning through. Next I drilled the 3" hole and repeated the bunch of holes air grate by drilling them in a piece of 10 ga. (Yes I used a hole saw. ) It lasted longer but was still problematical cleaning clinker and eventually burning out.

I replaced it with 1/2" dia. bar tacked with gaps and it works a treat.

The rest of my forge table is covered with fire brick and has a gap 2 bricks wide by 1 brick long over the air grate. I stack fire brick around it to define the fire size and shape I want. It's a sort of Duck's Nest forge with NO FIRE POT. I don't need one don't want one. I may not burn coal very often but when I do this forge is a treat to use. It's much easier and more efficient than my hand crank blown rivet forge.

Frosty The Lucky.

A plate on a union dosnt work so well, it's the crown of the Cap that sheds the slag. 

Personaly, I would just weld a wall on the open side and dump a bag of play sand in it. No need to weld the plate back in, keep the disk and sorce a 2" cap.  Note we usualy work from the side, and need to pass stock all the way grew the fire and off the far side of the tabble...

4 hours ago, Frosty said:

Welcome aboard Chris, glad to have you.

My big hardly ever used coal forge is a flat steel table 14 ga. I believe 3' x 4' with a 2" x 2" angle iron rim flange up. I won't go farther into it's construction other than to say you don't need plate for the bed, even under the fire. My tuyere is exhaust tubing, the vertical section is 4" big truck pipe with 2" horizontal for the air supply. The ash dump is an exhaust flap cap clamped to the bottom upside down. I welded a flange to the top end where it connects to the table. The table has a 3" dia hole drilled in it for the air. (I have lots of hole saws, wonderful tools they are.) My original design was a bunch of holes in the deck for the air grate and that worked for a couple hours before burning through. Next I drilled the 3" hole and repeated the bunch of holes air grate by drilling them in a piece of 10 ga. (Yes I used a hole saw. ) It lasted longer but was still problematical cleaning clinker and eventually burning out.

I replaced it with 1/2" dia. bar tacked with gaps and it works a treat.

The rest of my forge table is covered with fire brick and has a gap 2 bricks wide by 1 brick long over the air grate. I stack fire brick around it to define the fire size and shape I want. It's a sort of Duck's Nest forge with NO FIRE POT. I don't need one don't want one. I may not burn coal very often but when I do this forge is a treat to use. It's much easier and more efficient than my hand crank blown rivet forge.

Frosty The Lucky.

The base construction of your table is very simlilar to mine as you can see in the picture except that I cut a big round hole in mine.   Your idea sounds very interesting.  I like the idea of being able to adjust the size of the fire.

4 hours ago, Charles R. Stevens said:

A plate on a union dosnt work so well, it's the crown of the Cap that sheds the slag. 

Personaly, I would just weld a wall on the open side and dump a bag of play sand in it. No need to weld the plate back in, keep the disk and sorce a 2" cap.  Note we usualy work from the side, and need to pass stock all the way grew the fire and off the far side of the tabble...

I understand what you are saying about the cap.  I can get one close to work.  I have also noticed as you point out, many of the forge tables I have seen pics of are set up to work from the side.  

How important is it to work a klinker breaker into the design?

A clinker breaker is more for controlling the air blast than clearing clinker. Sure it breaks and clears clinker but they're more of a final valve and sort of directional . . . nozzle. No more of a deflector. Turned one way and there's a small slit so the fire stays localized, turned another way and the blast is spread out for a larger fire.

We'd have to start a poll but I don't think many guys using a coal forge use clinker breakers.

Below is a pic of my coal forge though there isn't much for scale except the bricks.

Frosty The Lucky.

Clinker breaker. I call it the Clinkernator. It destroys clinker. Twist the handle when the air flow is a bit diminished. How do I know? I listen for the whooooshhhh sound as I rotate the crank. I can also feel the resistance to turning the crank when the passage is partially blocked..

Awsome, thanks for the Pics.  As they say a picture is worth a thousand words.  

 

Frosty

I am really leaning toward your design.  I like the flexibility and as I really don't know what I am doing yet it will give am a change to mess around with differant configurations until I learn what works best for me.  

Chance not change

3 hours ago, SReynolds said:

Clinker breaker. I call it the Clinkernator. It destroys clinker. Twist the handle when the air flow is a bit diminished. How do I know? I listen for the whooooshhhh sound as I rotate the crank. I can also feel the resistance to turning the crank when the passage is partially blocked..

Awesome clinker breaker.  You should market those.

 

thanks. Yea, there is a demand for me to market my forge and blower pipe. I doubt I will. It works better than it looks. twist the handle and you never poke anything down into it. I use a commercial forge at this blacksmith shop who is nameless and it has a breaker.l It serves absolutely ZERO purpose. I have to jam a rod down into it, about every 15/20 min.

It's not MY design Chris, it's just old school clayed pan forge.  My big "shop" forge has a piece of 1/4" plate with 3/8" holes drilled in it for an air grate. I ended up closing most of the holes  with rivets dropped in them. I've used a forge with the bar grate and like it a LOT better.

My old pan forge has the original Buffalo(?) domed air grate and I just rake the clinker out as part of fire management. I've used an old "real" cast fire pot forge too and it was okay but I don't need a fire that big 99% of the time and coal costs $ so why burn more than I need?

Of course that's just my opinion and I'm a gas forge guy. I could be wrong.

Frosty The Lucky.

5 hours ago, Frosty said:

It's not MY design Chris, it's just old school clayed pan forge.  My big "shop" forge has a piece of 1/4" plate with 3/8" holes drilled in it for an air grate. I ended up closing most of the holes  with rivets dropped in them. I've used a forge with the bar grate and like it a LOT better.

My old pan forge has the original Buffalo(?) domed air grate and I just rake the clinker out as part of fire management. I've used an old "real" cast fire pot forge too and it was okay but I don't need a fire that big 99% of the time and coal costs $ so why burn more than I need?

Of course that's just my opinion and I'm a gas forge guy. I could be wrong.

Frosty The Lucky.

I liked what you were saying about using the fire bricks to form the fire pot.  I also like the idea of using a bullet grate.  

I dragged my pan forge out of the weeds and will be setting it up at the Mark Aspery workshop this weekend. I'll see if I can get some pics as I clay it and how it looks with the bricks in place. All I need to do is remember.

Frosty The Lucky.

8 hours ago, Frosty said:

I dragged my pan forge out of the weeds and will be setting it up at the Mark Aspery workshop this weekend. I'll see if I can get some pics as I clay it and how it looks with the bricks in place. All I need to do is remember.

Frosty The Lucky.

That would be great.   Thanks

Nobody wanted to burn coal but I didn't toss it back in the weeds it's standing out by the shop, maybe someone will want to come make stinky smoke. I'm not going to clay it till I use it, I didn't clean it out last time and I'm afraid the pan suffered for my neglect. I rarely if ever burn coal but I don't like letting even unused tools suffer unnecessarily.

Frosty The Lucky.