Home Built Forge 2.0

I am still very proud of my boys for building the large forge as their summer project. It was the first post I put on this blog. I did however run into an issue with the forge, it's a fuel hog. I figure that if you had 4 or more people all needing a forge at the same time the large forge is awesome but, unless you're working on something big the forge turns out to be too large for just 1 person. So a new project was born, to design and build a smaller more fuel efficient and more versatile forge. I again did some scrounging for materials and came up with what I think is a good design.

So I based my design on the brake drum ideas that are popular online. However I felt that the normal brake drum forges where too shallow so I got 2 matching drums and welded the open ends together. I then cut the top off to make a nice deep fire pot. I used some rebar for handles and supports and tubing for legs and tuyere. I also added an ash dump to this design. 

First thing that you notice is the handles. I made them taller and centered so that I can use a rod, pipe or anything through the handles to remove the lid or place the lid on while the forge is hot without being burnt. You'll also notice the tabs coming down from the lid. These lock into the ridges and keep the lid stable.

I wanted my fire pot to be removable for cleaning or any needed repairs. So to do this I welded small stubs of 1/2 inch rebar to the old rim to match the bolt hole pattern in the bottom of the fire pot. This allows the fire pot to easily be removed but, keeps it study for operation. The fire pot also holds down my diffuser plate. That way if it ever gets damaged it can simply be removed and replaced at a later date without having to rebuild anything.

I added the ring of rebar to act as a handle be able to move the forge when needed, to act as a buffer to help keep anyone from getting burnt and to give me a place to hang s few tools to tend the fire. The ring could also act a s a base for a support if I ever needed to add one.

Here you can see that I made a fairly deep fire pot in order to get some good controlled heats while at the same time attempting to conserve fuel. Both the large forge and this small forge were built with the idea of using wood and charcoal as fuel but, from what I've been told coal or coke could be used as well. I don't know of any coal suppliers near me in the middle of the Arizona desert but, we have lots of mesquite hard wood. I cook with mesquite cuttings all year long and always have some on hand.

I also did some research and found out that the EPA allows you to burn used oil and wood scraps form construction sites to pallets as a fuel source in forges, heaters, boilers, foundries and more. According to the EPA this is allowed, legal and considered recycling because none of it ends up in landfills and since it's considered waste the EPA sees it as using that energy for another purpose with little to no waste product left.

You can see here that I made 2 removable cutouts. I bent some rebar to match the curve of the fire pot to attach to the cutouts. Then I added 2 upright bars connected to the fire pot at an angle so the cutouts could be removed when needed.

My idea here was to be able to remove either side as needed or for longer work I could remove both cutouts in order to heat small sections at a time.

The nice thing about this design is the flexibility. This allows me to use a relatively small forge for many things and since the smaller forge is more fuel efficient I can conserve fuel, which is always a good thing.

Here is a picture with the cutouts removed and the top on. I plan on using this option for anything that needs concentrated heat like the forge welding of pattern steel.

Also I left the bolt and axle holes open in the top. I wanted use the top to get a chimney effect but, not blow all the heat out of the cutout openings.

I also had planned to use the cutouts in place and the top on when I was finished in order to help extinguish the fuel rather that just burn everything out every time.

Just a note on the fire pot. As you can see from this picture I did not try to completely weld the seem of the 2 brake drums. I was afraid that if I did then the weld may crack during a heating or cooling cycle. Once a crack starts it will run the entire length of the entire weld. So by only welding short beads if one cracks I don't have to worry about the entire upper half of the fire pot suddenly coming apart from a  crack that occurred during a heating or cooling cycle. This would be very bad to have happen while the forge was being fired. So I thought it would be a good idea to try and avoid that and not make a continuous weld.

I added an ash dump on this forge. The angle iron that I used wasn't wide enough so I had to add short triangular pieces to each side to make the closer wide enough to seal the bottom of the tuyere pipe. I just used 2 oversized nuts for the hinge point welded to 2 small steel plates to provide enough space for the pivot. I used a nut and bolt or the pivot pin and welded the angle iron to the pivot pin. I lined up the angle iron and the bottom of the tuyere to get a good seal and welded the steel plates to the tuyere.

I also decided to weld on some counter weight to the end of the angle iron to counter act the force of the air coming in through the tuyere. Depending on the force of the air that I need to use I ma have to add a little more counter weight.

Once I use the forge for a little while and I make sure everything is working right I'll give it a coat of black heat resistant paint to clean it up.

I also wanted to say that all of the material I used foe this forge was also scrounged for free so there was no cost for any of these materials.

The only other thing that I may end up doing is to add some clay and sand refractory around the base or the fire pot inside the old rim to help reflect the hat back to the fire pot instead of radiating out. I'll use the forge and test it out first to see if I need to add it or not.

I hope this has helped answer some questions or maybe given you some ideas.

Home Built Forge

Two of my teenage sons decided that instead of sitting around playing video games or staring at the television this summer, they wanted to build a forge and learn how to use it. I figured this was a great idea. They have been interested and wanting to learn blacksmithing for some time and I feel that these are great skills to have. So we begin our adventure in blacksmithing with our home built forge.

My two boys Jason and Charles invited their friend Jordan over to help with the project. I want to say that I'm proud of the three boys, they did the majority of the work.

We started out looking for materials to build the forge out of so we didn't have to spend any money. We found a steel drum, rebar and galvanized steel fence posts to use.

We split the steel drum down it's length. Charles got the fun job of cleaning out all the dried paint out of the drum. 

 

 

 

We then welded the two open ends of the drum together to form the trough of the forge.

After welding the trough together we cut some of the tubing to make a frame and started welding the frame and trough together.

Here's Jordan welding up the frame to the trough. This was Jordan's first welding experience and he got right in there eager to learn and do it. He did pretty good.

The next step was to measure and cut the angle on the ends of the legs so we could attach them to the side of the frame and trough.

Here we're setting the legs in place and tack welding them. After I tack welded the legs in place I let the boys finish up the welding.

The boys really did most of the cutting and welding. I only supervised, taught, explained and fixed a few things. They did almost all of the work.

 

 

 

We cut and welded some smaller pieces of pipe to act as supports from the frame to the legs. We also cut and welded rebar across as a brace between the legs. Finally we cut the legs down.

Here is the forge for the first time standing on it's legs. After we stood it up for the first time we cut, ground down and filed the edge of the trough so that it was fairly level and not sharp.

Next was to add the tuyere. Ya I know, you asking what the heck is a tuyere? Basically a tuyere is the air pipe that you attach to a bellows, fan or other forced air source.

The forced air is what increases the heat of the coals in order to get metal to the desired temperature. The more air the higher the temperature. 

 

Also you'll notice that one end of the tuyere extends away from the forge. This is for the connection to the forced air source. The other end will just have a removable cap so that it could be use as a clean out if needed.

So now that the tuyere was welded in place we need to come up with something to use as a diffuser. The job of the diffuser is to distribute the forced air evenly so all of the coals are heated the same at the same time producing even heat through the forge.

We had some very hard steel posts with holes in them all the way down the front. The posts reminded of street sign posts with holes to bolt the signs through. 

We cut them to length and then set them at an angle so there was an opening in the center and the holes were pointed to the sides. I welded only about one inch every six inches or so. This was to allow the center slot to stay open for air down the center.

So now that we have our diffuser done our next step is to place the forge out in the open away from anything flammable.  We cleared everything so we were down the dirt, and here in Arizona we have a lot of dirt! Now that it's in a safe place to use it we can move on to the refractory.

Ok what is the refractory and why are using it? The refractory is a substance used to reflect the heat back towards the coals. This helps to concentrate the heat towards the center of the forge where the metal is placed. The refractory also helps to protect the metal barrel and frame from over heating during use.

 

Since we do have so much dirt here in Arizona and the clay content is so high we used the dirt for our refractory. We also went to a local wash (dried stream bed) to collect sand to use in the refractory mix.

We used a screen to sift out any rocks, organic matter or anything other than fine clay particles and fine sand.

We mixed the refractory and applied it in layers. 

For the first layer we mixed two parts sand to one part clay. Only enough water was added to make the mix stiff and sticky.

We let the base refractory layer dry in the 110 degree weather so it didn't take too long. 

We the places a small amount of charcoal down the center on top of the diffuser. I wanted to dry the refractory a little faster and find the cracks caused by the heat early so they could be filled before the second layer is put on.

The first firing lasted for about an hour. When it was done several cracks had appeared but, overall the refractory stayed intact and worked very well.

We waited until the next day and cleaned out all of the ashes. We then made another mix of the refractory. 

 

This time however the mix was made one part sifted sand to one part sifted clay. The refractory mix was also mixed a little wetter than the first batch so that it could be pressed into all of the cracks.

A wetter mix is stickier and adheres to to the first layer better.

We applied the second layer to make sure there was enough thickness to make to refractory even and effective.

We'll have to wait until tomorrow to check for cracks and begin to fire cure the refractory.

We did also spend some time building a box to house a a recycled vacuum impeller and motor. Unfortunately the motor bearings self destructed after it ran for about 10 minutes. So we had to scrap that part of the project. 

 

Our current backup forced air supply is to use the exhaust port from a shop vac. We've tested it and it seems to work well enough.

Tomorrow we'll check for cracks and fill anything that have shown up and maybe begin to fire cure the refractory. 

I'm proud of Jason, Charles and Jordan for all of their hard work.