Budget Heavy Duty Propane Forge
by nevadageo in Workshop > Knives
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Budget Heavy Duty Propane Forge
My goal was to build a budget conscious high quality forge that would last for years to come. I built it fairly large as I was planning to forge knives and tools. You will want to build it as small as you can get away with as the larger a forge is the harder it is to heat up.
I used 1/4" diamond plate as it was what I could buy cheaply from my local steel yard in a scrap cutoff. You could probably use 1/8" steel plate as well.
I also designed all of my dimensions around split fire brick so I wouldn't have to try to cut any.
Wear proper PPE for this as there are a number of dangers to your health.
DO NOT USE GALVANIZED STEEL- it will vaporize with toxic gasses when exposed to heat and put you in the hurt locker.
As with all DIY and especially forging products- this stuff is dangerous and I'm not liable if you get injured.
Supplies
Forge
10 split fire bricks 4.5 in. x 9 in. x 1.25 in. Fire Brick (6 per Box)
1 package of kaowool (this stuff is toxic when exposed to flame so please please please cover it with firebrick)
two 11"X15.5" steel plates for top and bottom (many steel yards will cut these for you and save you a lot of time
two 9"x15.5" steel plates for the sides
four 9"x2.25" steel plates for the vertical end pieces of the forge
four 6.5"x2.25" steel plates for the horizontal end pieces of the forge
four square tube pieces of desired length for legs
two 8"X 11" steel plates for shelves
Burners
This is my poor mans imitation of some great burners by Ron Reil. Read his page for more info. https://ronreil.abana.org/design1.shtml
two 3 in. x .75 in. IPS Black Iron Reducing Coupling for the inlets of the burners
two 3/4 in. x 18 in. Black Steel Schedule 40 Cut Pipe for the tubes the gas mixes in
two 1 in. x 3/4 in. Black Malleable Iron FPT x FPT Reducing Coupling until you can forge your own flares- these should work acceptably
two 1/4 in. x 6 in. Galvanized Steel Pipe Nipple for the gas tubes in the burner inlet
one 1/4 in. Black Iron Tee to connect these to the main gas inlet
one Black Steel Pipe, 1/4 in. x 11 in. Nipple to extend this high enough above the forge to make you not worry
two 1/4" black iron caps
one ball valve to shut off propane flow at the forge.
one High Pressure Propane 0-20 PSI Adjustable Regulator with QCC-1 type Hose (I have a ten foot hose to keep the tank far away from my work area while forging.
fittings to connect your 1/4" black iron pipe nipple to the propane hose. This was one of the most challenging steps as the stores in my area didn't have anything simple and I had to use a few adapters
Propane safe teflon tape
tweco weld tips I used 0.030 but you will want to have a few sizes on hand to change the jetting and get your mixture right.
two Black Steel Pipe, 2 in. x 3" long or thereabouts to weld to the top of the forge and use with the set screws to hold the burners at the right height in the forge.
six 5/8" bolts for set screws
Step 1: Start to Build the Box!
Weld the two sides onto the base plate
Step 2: Add the Vertical Steel Plates
Step 3: Add the Horizontal Steel Plates
Step 4: Add the Kaowool
I don't have any photos of this- but we are going to add enough koawool to give an inch of insulation with the firebricks sitting on it. Use gloves and a respirator! This stuff makes fiberglass insulation feel tame. You want to have an inch of kaowool on the bottom, the sides and the top with the fire brick sitting inside of a kaowool burrito.
Step 5: Add the Layer of Firebrick to the Bottom
Step 6: Add the Firebrick of the Sides
Step 7: Add the Firebrick of the Top to Make a Tunnel of Fire Brick.
The opening should align with the opening in the steel plate.
Step 8: Cut Holes in the Firebrick for the Burners
I tried a number of things to drill and cut holes for the burners. I kept cracking it. I finally realized that if I used a grinder I could grind semi circles in two bricks and make a hole and that they would be a good distance apart.
Use a respirator and eye protection!
Step 9: Finish Adding Kaowool
Finish packing the void spaces with kaowool- and add a blanket to the top which will fill the space completely when you put the lid on.
Step 10: Set the Lid in Place and Draw the Holes to Be Cut
Use a sharpie to draw the outlines of the holes in your firebrick and then use a hole saw to cut the holes out.
When done put a few welds in place to hold it, but not so many you can't cut it to maintain this in the future.
Step 11: Drill and Tap the Set Screw Holes and Weld the Collars in Place
Take your time to tap these right- you want to make sure they pinch in towards the center to hold the burners securely.
Step 12: Build the Burners
Build your burners. I initially welded the black iron pipe and regretted it when I had to make adjustments.
Step 13: Tune Your Burners
You will want to follow Ron Reil's advice on tuning the burners. You don't want the dragons breath in one of these photos. Also It took me some time to get them tuned in well.
If I were to do this again I would run a line to each burner so that I had more flexibility to tune them.
Build a choke for them- I use worn out cut off disks as I haven't taken the time to build a proper choke.
Step 14: Throw Some Legs and Shelves on It and Forge Some Stuff!
Conclusion
Thanks for taking a look at this. I hope it was helpful. II have to thank my Uncle Ray for showing me the love of forging. I have to thank Alec Steele for inspiring me to finally get started in blacksmithing. I admit that I based this design off of one of his forges he had made early on in his career. Thanks Alec for your inspiration!