Propane Forge WIP

This is my WIP for my forge. With December being such a busy month, I finished assembly but haven't fired it up to dry it out yet (I will explain later). I am planning on doing it tomorrow, and I can post some updated pics at that point. I will include various measurements and why I did what I did. Questions are welcome.

I am extremely knew to knife making. I've not built a knife yet. I have plans for everything, and tons of books, but I knew I needed equipment first before I could get going. I'd decided after being allowed to participate in smithing a few things with a friend that I would learn to forge knives. I wanted to assemble tools slowly, and I honestly felt I could build my forge cheaper than an assembled version and also one that is better suited to what I *think* my needs will be. So, with that I decided to get started on my forge.


I searched everywhere for information, and tons of plans and examples were available but most were for coal forges or used Kaowool or equivalent fiber based blanket. I'm in Florida, and coal isn't readily available, and also with neighbors, I figure the smoke might not be wise. That is why I elected to build a propane forge. I didn't like the idea of using such a potentially dangerous material as the Kaowool or equivalent. That is why I elected to use 2600 degree soft firebrick (I could have used 2300, but I prefer to overbuild!). The bricks I purchased are 9" long, 4.5" tall and 2.5" wide. I sat down to draw up a plan of how to configure the bricks to create a chamber. I knew that I wanted to keep my forge small. I'm just starting out and anything I could expect to forge would be small, plus it is more efficient to heat and also means I can get temperatures as high as I could ever want. I initially created a cube design, but didn't like it as it wasn't very deep. I also read somewhere that having a rear opening can come in immensely handy at times. Even if I some day wanted to force a blade that is 15 inches long, I can easily accomplish this despite my forging chamber being only 9 inches long, 4.5 inches tall and 4.5 inches wide. I tried a few different ones and finally settled on the one you see below (the Door views were actually added to my plan AFTER my initial rough assembly, I will explain why later). I had heard the bricks were soft so I ordered 12 though my plan only calls for 10. I thought if some were damaged in shipping I would still be able to get started or if I damaged one and couldn't use it, I'd have a back up. They came in perfect shape and it turns out the extras work out since I can carve slots in them to hold hot steel as it cools.

The bricks only create a box whose front is 9.5" Tall by 9" wide, with a depth of 13.5".





I started a rough assembly just to see if there were any kinks I hadn't anticipated. Which there were! First was the door. I almost started cutting it out square, but I realized that if I did there was the potential for it to get off center and could lodge. I didn't want to chance that, so I decided to cut the sides at an angle to form a trapezoid (top down view). I guess you could say it looks like a pyramid with the top cut off. This shape assures me it goes in the same way each and every time, it can't get lodged and it can't go in too far. Next issue, how do I cut the top of the door? It is in the middle of this brick, which is VERY fragile. You can literally cut grooves in it with your fingernail. Its at an odd angle so I can't use a drill press (at least not mine) and I don't have a mill. I'd like the door to remain as close to the size of the opening in order to minimize heat loss. Since the brick is so easily cut, I thought of a rope saw. I didn't have anything small enough, but I did have picture hanging wire. It worked amazingly well! Since it was woven it kind of added to the cutting action. Keeping it parallel was difficult, but I had drawn lines on the brick to guide me. I also just made enough room to pass the hacksaw blade in, and used that the rest of the way.

This is the front of the Forge, showing the front door opening. It doesn't quite show the door angles, but there will be some later that do.



Once I stacked the bricks together, I had to move them. I had placed them on a board I had and as I moved them, I noticed the side bricks both moved very easily. While I had decided that my frame would have side braces to prevent them from falling out, I hadn't thought of them falling inwards. The front and rear bricks which had doors had an extra 1/4 inch each extending beyond the floor and ceiling bricks. I decided to cut 1/4 inch from each interior side of the front and rear 'door' bricks. This resulted in a flush exterior and also a point of contact for the side bricks so they could not fall inwards. This can be seen in the below picture.

Top view of the rough assembly. The front door is also showing with the angles more prominent.


Side view of rough assembly, the small slivers in front are where I cut out the back sides of the bricks to prevent the inward sliding.



I cut out the rear door and put the rest of the bricks together. This is the view through the chamber and out the back.




More information to follow!

I didn't take any pictures of the frame assembly. Honestly I wanted it to get done because I was in a rush since my helper was leaving! I decided to use angle iron since it was sturdy and would help hold the bricks together with out needing to use fasteners in the bricks at all. Remember, this stuff is very fragile so I tried to avoid any excessive cuts or removal of material. Also, since it is fragile, I've heard that sometimes you need to replace bricks, so I had to build the enclosure in a way that allowed for disassembly and repair. I decided that I could weld the side frames and use stainless steel bolts and nuts to lock the crossbars to the sides. Below are my drawings, nothing is to scale. It was to give me the idea of orientation so that the angles iron held the bricks in and also was structurally stable. While not heavy, the entire piece isn't light either, so I wanted to be sure it would hold up.





I got the angle iron from Home Depot and used my compound miter saw with a metal cutting blade on it to cut the frame pieces to the correct size. Before the cuts though, I had a thought. I knew I had seen LOTS of forges with a kind of tool rest out front. I decided to add this to my frame since I had to extend the bottom of my frame a few inches for the platform I would be setting it on anyways.

Here are the measurements of my pieces:

Base or Bottom 20 1/8" x 2
Top 16 1/8" x 2
Side bar 14 1/8" x 2
Crossbars 9 1/4" x 4
Verticals 9 3/8" x 4
Tool Rest Vertical 2 3/8" x 2
Tool Rest 9" x 2
Burner Holders 7 1/2" x 2

The frame parts which would fall on either the Left or Right side were welded together. So then I had a left side, a right side and 4 crossbars. I put 3 bricks in between the left and right sides of the frame as the base/bottom. This allowed me to place my crossbars tight to the brick and mark my holes. I then removed the bricks and drilled the holes for the bolts to go through. I then bolted the crossbars in, assembled all of the needed bricks and marked the upper pieces for drilling. Removed bricks, drilled, etc.

At this point, I fully assembled the forge, minus the burner. I figure that sharp corners could only hurt me and cause HUGE issues if I cut myself bad enough to drop 1200 degree metal! So I popped a flap wheel on my angle grinder and removed any corners or sharp edges I could. Once done, I disassembled and cleaned all the parts up with acetone. I let them dry and then painted all the surfaces with Rustoleum high heat black. I don't know if this step is necessary, but I thought it would good and I had an extra can laying around.


Now I'm ready to slap it all together right? WRONG! I had read that some people had issues with propane forges getting hot enough. An often recommended fix was the use of a ceramic coating compound called ITC-100. This stuff will reflect the heat back in to the chamber that the bricks would have absorbed. It allows for less fuel consumption and also it heats up quicker. I ordered a quart and decided I would apply it to the inside of my forge up front. It also serves to protect the interior floor of the forge (minor protection). Remember, this brick is soft!

One thing I had to do though, was cut out the entry for the burner I had built. I followed the plans out there based on Ron Reil's design. They are everywhere and all you have to do is search google for them! I opted to install the burner brace pieces on the right side of my forge, which allowed me to angle the burner in from right to left. Most of what I read said reflecting the burner blast was best for your work pieces and to allow the firebrick to insulate the end of the burner so it doesn't melt!I tried to angle the burner so it would bounce off the left side of the forge and also didn't allow the end of the burner to exit in to the chamber. I believe the firebricks insulate the end so it doesn't melt quite as easily. To cut the hole, I used a 1/2 drill bit to get the angle I wanted and be a guide. Then I just went very slowly and used a hole saw that was the correct size for the end of my burner.

Now I assembled the frame with the bottom crossbars and then added the floor bricks. I then added the next level of bricks as well, but left the top bricks off. Those I clamped together (carefully) off to the side so I could apply the ITC-100 to the under side since once on, I could never reach through that small doorway to them! The ITC-100 stuff is a gray color and they say should be the consistency of a thick milkshake. I used a spray bottle to add water and just mixed it for a few minutes until I had what I thought was the right consistency. I then painted it on with a disposable paintbrush. I applied two coats to the interior chamber faces and let them dry.

Here are the top bricks with ITC-100 applied. Notice how I also applied some of the coating in to the hole a small way to help keep my tip from burning?



Here is the side of the forge with the ITC in the chamber, but this mostly shows the left side frame.



Top down from the front with the ITC Coating. I'm using clamps to squeeze the burner in the braces, which is why the C clamp is there.




Once I let the coating dry for a few days, I assemble it together. Next post for fully assembled pictures, nozzle in place.

One last change, I didn't mention it because it was during final assembly. I had a few inches of angle iron left over so I cut it in half and attached them to the doors with very very large thread screws I had. I'm sure even Tapcons (screws for concrete) would work. You just want the widest threads you can get so it isn't able to just slip out of the material. I did this because I thought that the doors might be hot and I might rather use tongs to remove them then my hands!

Here it is, all done.......













I know I'm new and haven't earned my stripes yet, but I hope this helps someone in the future. I figured with as many questions as I'm sure to have, I better contribute where I can!

Thanks for checking it out!

Teter09,

Where abouts in Florida are you from ? We've got alot Florida makers here at Knifedogs.

Very nice job on the WIP !

-Josh

Thanks Josh!

I'm in Orlando, over near UCF. Glad to know about the abundance of Floridians here, I am bound to have to buy a few beers so I can watch some of them. I learn visually a lot quicker then reading things.

Ok, so here's my take on your forge build: The soft bricks, while they reflect more heat than the hard bricks (which hold more heat) will not last long. If you plan to forge weld, they'll be gone after your first attempt. If you are determined to use them, think about making the bottom of the forge from hard brick and go up one tier on the sides (laid flat) with hard as well.
I do forge work daily and have built many forges in the past 20+ yrs. Some have been better/last longer than others. I use a ribbon burner, but heat source has no effect on forge longevity.
I like using the hard bricks with kaowool on top.
John

I will take the hard brick under advisement. I assumed at some point I would need to replace bricks and the design allows for this since the crossbars are bolted on and not welded. Why the kaowool over the hard brick? Wouldn't a ceramic coating help reflect the heat more than the blanket?

Nice WIP! Now we need to see a shot of it in action.

I finally had time away from work in order to heat up the forge for the first time. Here are the pictures from the first heat, though I have a few notes since I've tried it a few times since...

First observation, the doors definitely help heat it up faster and I'm glad I created them in the way I did. It makes it very easy and without worry to pop them in or remove them.

I don't know if it is the ITC 100 compound or if I just made the forge small enough but heating a piece of angle iron i had laying around took no time at all. Perhaps a combination but from room temperature to bright orange didn't take long at all.

In creating the burner, I added a pipe nipple at the top which I drilled and was going to add a kind of flume like a chimney. Turns out this was exactly the right way to go in order to help fine tune the burner. At around 1 -1.5 PSI it can be a bit touchy!

Hope this helps someone, or at least enjoy what I think was a very satisfying build!