I am newish to smithing (1 year or so) and I took it upon myself to build a propane forge out of an old 20# propane tank. I lined it with 2" of kaowool, then satanite, then I realized that i needed more bulk to level the bottom and used some hard firebrick. Then more satanite to bind the firebrick together. Then i put down a layer of ITC-100. Then finally I used some bubble alumina to create a flux-resistant lining on the bottom. I have 2 homemade Ron Reil style forge burners pointed down from the top, with a needle valve each and a T-connector to a propane regulator that supplies up to 30 psi of propane. THe front opening to the forge is about 6"x3" and the back opening is 6"x2". I have tried to narrow that with firebrick to create more backpressure and keep in more heat to raise the forge temp to no avail.
My problem is that I can’t get it hot enough. I am nowhere near forge welding temp even with the forge running full tilt for a while. I have a few concerns but don’t know where to focus to get it hotter and was hoping for some help from this group to point me in the right direction:
- I read that using hard firebrick will absorb a lot of energy before it heats up. Could this contribute and do i need to dig that out and replace it with kaowool+satanite to fill in the bed?
- my forge burners aren’t performing super well I think. I get a lot of sputtering from one of them and my biggest concern is that they’re not loud enough when they’re running full tilt. I read that they should make it hard for someone to hear you speaking when near the forge - they don’t do that. I think that there is a problem with inducing air via the venturi effect and I don’t know how to tweak the design to fix that. I tried different tweco tip sizes (0.035, 0.030, 0.025) to vary the volume of propane to try to induce more air but it just makes the flame richer and burns through my propane super fast. My tips are fairly centered i think. I do wonder if the distance from the end of the tweco tip and the beginning of the burner tube is not right. The flare fitting i have at the end of each burner tube is a 3/4" to 1" reducer with the 1" threads burred off. It keeps the flame from blowing out but I wonder if the taper is too fast and that could affect the venturi effect and reduce the amount of air drawn in.
I’ll post some pictures soon on this thread but I would greatly appreciate some guidance from some of you pros. I could also bring the rig into DMS sometime.