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I Forge Iron

The 55 Forge, bottom and side blast.


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The following is a quick summery of the 55 Forge. More in depth design and discussion can be found on the site.


The original 55 Forge was bottom blast. The fire shown is a little shallow, so if there is a question, just add more fuel.



The  tuyere was a piece of auto exhaust pipe with 1/4 inch holes to accept 1/4 inch round bar in a X pattern to form a grate. Lots of open room for air to move up and into the bottom of the fire.



The next test modification was to put a brake drum into the 55 forge as a fire pot. You can see the cone shape to the ash and the rim of the fire pot. The bricks were added to give the fire more depth for the project at hand.


Ash will build up to the top of the tuyere in the bottom blast in a fire or two. There is a T configuration below the bottom of the forge that is not shown. The T section is close to the bottom of the forge and the down pipe is 12 to 18 inches long (what ever you have on hand).  Clinker is not really a problem due to the size of the tuyere. Just let the fire idle for a minute or two and the clinker will solid up and can be hooked out. Ash will at times fill the down pipe and need cleaned out.

I have run this forge using coal dust or breeze. Once the fuel starts to coke ( a couple of minutes into the fire ) there is very little fuel that falls into the down pipe.


The next modification was to make the 55 Forge a side blast forge. Just cut a slice in the side of the wall and add an air pipe. The depth of the slice was to the top of a house brick laid on its side. It was available. The fire shown is a little shallow, so if there is a question, just add more fuel.


I like this design as it is so simple to build and works. That is an aluminum clothes dryer vent pipe being used to transfer air from the blower to the forge. With the side blast version the ash and any clinker builds up under the fire. 


On either 55 forge, the cut edges of the metal as they are sharp. You can roll them over, or cut a 2 inch piece of metal from the parent drum, fold it in half long ways, and place it over the cut edge of the metal pan. 


The 55 forge was developed so that any one in any third world country could have a forge with little or no cost.

The forge runs on solid fuel, coal, coke, wood, charcoal, lumbar, pallets, etc. As has been stated many times before, Fuel does not make the fire hot, Air makes the fire hot.  If there is a question about how hot, then add more fuel and more air.  It can and has reached welding heat. It has also melted the metal if you do not pay attention to what your doing. ( Do not ask how I know this as I was not paying attention.)

The 55 Forge is a great design that is simple and works. It is easily modified to adjust the size of the fire pot, the depth of the fire pot, different tuyere configurations, and the list goes on and on. Folks thought a brake drum was needed, so I tried both a brake drum and rotor. Each has advantages and disadvantages and in the end were not required. It simply adds a level of complexity to the system and overcomplicates simple. The fun part of the 55 Forge is make one, use it, modify it as you wish. When you finish there is another 55 Forge on the other end of the drum as a spare.

The label on a drum is NOT accurate, it only means that is what the drum contained just before the label was applied. I found a empty drum at a auto repair shop. The label said 5W30 motor oil with a brand I immediately recognized. Somehow the top of the drum was hooved or domed a bit. When I removed the bung plug from the bung hole there was release of pressure and an overpowering aroma of gasoline and other very volatile materials. I ask the shop manager about the drum and he said "Oh that was the one they used for racing fuel last weekend."  

ALWAYS choose a drum that you can pronounce what it contained before you brought it home. NEVER use anything that throws off heat or sparks when you open a closed container or drum. If in doubt, have someone else cut the drum in half while you go get a burger and fries for the both of you for lunch.

The 55 Forge is just a way to get you started quickly, so you can play in the fire while you research and plan on what your second forge design will look like.

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  • 10 months later...

Glen, correct me if I'm wrong. Looking at the picture and reading the description on the side blast 55 above it looks like..

First you cut the end of the drum off to about 6 inches or so.  Then you notched out for your tuyere so it would be level with the edge of a masonry brick. It looks like you just packed coal all the way around the drum, level with the top of the tuyere brick, with a larger mound in the center of the drum. Then run your pipe across and in to the bottom of the mound in the center. Hook your air supply up and get some flames going.

Is that pretty much the size of it?

And I guess from there if you wanted to tweak it a little you could fabricate a hood and flue for the top and maybe a decent stand to set it all on.

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That is the simplest form,  a bit more elegance can be obtained buy not cutting all the drum away/ say cut all but a third, cutting up and then back to the front. If this is a deheaded drum split the front and forma cone to attach the flue. 

I personally recommend a hole to fit 3/4” schedule 40 pipe ( heats 1” easy) 5” from the top of the pan or optimally 6” for coal with side notches. Ash and fenders are classic fills but cheap cat litter may be a good substitute. Charcoal can’t be used to bank the fire so fill must be used.



The drum is the box that holds the dirt. The dirt shapes the fire. Again not strictly necisary with coal but it takes a lot of fuel to compleatly fill the table.


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Charles is correct and for simplicity start with the Just A Box Of Dirt design he suggests. It is a quick way to get a fire started at little or no expense.

This was the original 55 forge design which has been modified as it was used.  24 inches takes a lot of fuel (all of which is available for use) at the beginning.  That is why you see the bricks, to reduce the interior diameter of the forge, and deepen the fire. The beauty of the system is that you can change things and make the fire smaller, larger, deeper, etc as you need it for the project at hand. 

When I switched from coal to wood as fuel, the drum was cut about !/3 of the drum tall (12-16 inches) with a slot down one side so you could put the metal into the fire at whatever level you wanted. The rest of the drum would hold the wood, charcoal, and embers making the fire deeper. The embers would burn turning the charcoal to embers, the embers would turn the wood to charcoal, and new wood was added to the top as the fuel was consumed. 

The 55 Forge was, and is, a constant work in progress with many changes and modifications.  The only perfect design is the next one your about to build with the modifications your about to try out. (grin). 

Do not worry about cooling the side blast forge air pipe with water.The original 3/4 sch 40 pipe has not deteriorated since it was put in use. That has been several years now. And if it does start to show deterioration, just push it forward a bit. Pipe is expendable and cheap.

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Charles, you mean you can take a 55 gallon drum, remove the heads, then split the metal cylinder down the side to make a piece of 3 feet tall by 6 feet long piece of sheet metal for other projects? What a concept !! and a great source of sheet metal !! (grin)

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That’s where I thought you were going.

 The 55 forge series was an early inspiration. I have an aldays and onion style forge with constatina style bellows I built (I have to go back and change the valves). And have a couple of othe 55 forge builds in the planning stage. 

Buy using the conveniently sized pan and a convenient fill to fill the extra volume and shape an efficient fire for the job at hand, the 55 forge is a winner. Even more impressive is the fact one of our members built one on a mission trio to South America.  

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  • 1 year later...

I have an abundance of 55 gallon steel drums but they have an epoxy liner because the stuff that was in them before was not so friendly (I've gotten them all cleaned out from that crap) but i was wondering if anyone has had issues like this??? i know that it is inert and isn't really harmful but that was in reference to smokers and forges get a bit hotter so i was curious. Any input would be greatly appreciated!

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Personally, I would prefer a original drum that contained something I could pronounce, such as oil, grease, antifreeze, washer fluid, etc.  If you seek them out, these drums should be available. GTTS or go to the source such as a service center, truck stop, or somewhere that uses material in a quantity of 55 gallons at a time. Drums can be purchased new, but what is the fun in that?

A hole in the ground will work, Raise the hole in the ground to a convenient height, such as on to a table, and it is still a forge. A stack of bricks can work. You do not need a 55 gallon drum, The drum was chosen as a building material because you can find one most anywhere in the world, and even 3rd world countries. Look for any container such as an old hot or cold water tank, a plow disc, or some wood, and build a box (did I just say that? LOL)  Use what material is available to you at your location.

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I don't like building a fire in a mystery drum, even cutting them is dangerous and using a torch or cut off saw can be suicidal. A barrel header might not work so well having to break out an epoxy liner and a jig saw can strike sparks.

Once you've managed to cut it enough dirt could keep the drum from getting hot but it'll also absorb fumes and carry them to the fire.

Epoxy liners aren't used for common stuff. It really bears thinking about.

Frosty The Lucky.

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I have seen sparks from using a chisel and hammer to cut metal. 

Known drums from a known source can be a problem. I ask and was given permission to load up an Valvoline 10w30 oil drum outside a building that sells and repairs motorcycles, ATVs, quads, etc. Had it in hand and was about to put it in the truck when I noticed the top was hooved just a bit. Opening the bung hole let off a hiss (pressure). Ask the fellow about it and he said Oh, that was the drum we used to take racing fuel to the track over the weekend. I left it beside the building.

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  • 3 years later...

I think one advantage of bottom forge is that metal can be heated more on longer spot.
Yeah you cant hit at 4 inches good   in les then 10 seconds,  but, when steel get cold and you for example want to heat other spot for second heat sometimes in side  blast forge you will be limited at specific space.

In bottom blast forge i think you can choose if metal is heated more then you want it , just dont hit that spot, while you dont have sometimes that advantage at side blast forge.
For example forging tong reins is real struggle in side blast forge.

And  one disadvantage of bottom blast forge is that you need pipe bigger than 2"  in diameter , becasue ash get clocged easy at T spot

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