Hey from one guy trying to learn this to the next here is some documentation of what I am doing to get an idea of furance size, material quanity and construction plans. This has been helpful to me to get an idea of what I want, what I don't want, and design flaws. If you are looking to make a schmick furance system the design considerations (thermal efficency, operator ease, and safety, etc.) and expenses are important factors that demand some time and attention. I wanted to do a bit more than a back of the napkin estimation schematic. This was helpful to me to better understand the design and wrap my head around what I wanted to do and not do. It's suprising how many dumb ideas we just skip through our head until it makes it on paper. This is a progression of my designs, originally on a piece of tape, to some yellow paper, to the computer and then back to some white paper drafting. As all veterans recommend start with the crucible!It is the central part of the whole operation and after many redesigns I have come to appreciate this tip more. My first attempt came organically from trying to compare crucible sizes while looking the charts online like this crucible diamension chart . (I settled on using A8 and A16 crucibles) Keeping it almost 2D I just plotted the crucible sizes on a piece of masking tape on my desk. Creating a center line and working out from there. Naturally I started to theroize my furance inner wall dimensions and plinth size. From there I transfered the tape to some paper to make it slightly more diamensional. I also put some high tech sticky notes to flip back and forth on wall diamensions and such. At this point I had a simple schematic of my furance based on design parameters specific to my furnace ( burner needs, operating temperature (metals to be melted), and working operations). I spent a lot of time looking at other people's furances and plans. From there I went to re-drawing my design and did a 1:1 scale of my base shell ( it is a three part furance, gingerly inspired) I also learned that simplicity makes reading these a lot easier. I got a little carried way with differentiating the different materials plus add the legal paper lines and it got a little much. (Keep it simple stupid) (Some might argue that this approach is too complicated as well but it was helpful to my understanding and concrete visualization). Then I tried to do this in fusion 360 but with being self taught I could not control it to design what I wanted well enough. After rebuiliding it 6 times on the computer unsatisfied, I went back to the old school drafts to express my designs. ( That's what you get for trying to be fancy, waste 2 weeks of free time). One day I was mulling over the plans and frustrated with the computer while I was out side and I started plotting it in the sand. Quickly I switched to a large piece of cardboard, a straight edge (level), sharpie and a pen. I did a full 1:1 scale and ploting which gave me a nice visual to what it will be like. ( Certainly quicker and more satisfying, this took my only 40 minutes to get all the details down) Lastly to finalize the design I did a 1/2 scale of the design again so that I can upload to the forum for some drafting review on diamensions and some input from the boys. (Specifics of that will be in another post). Cross sectional View Top view Dummy Design ( Final simple schematic to get that basic idea without a barrage of measurements) By now I can say that I have a pretty good idea about my plans and I have a lot of the diamensions memorized. If it is your first time like me I would recommend the crawl, walk, run method like myself, but prehaps a bit more streamlined. 1. Tape on desk/ single plane 2D sketch (Start with crucible diamensions! and a serious thought on what kind of casting you want to do with THIS specific furnace.) 1.1 Have an idea/schematic of what you are shooting for 2. Card Board 1:1 sketch ( may take a couple, my errors where ironed out on paper first) (Optional) 3. Draft, if you want review or a nice crisp plan. Schematic so that you don't get lost in the sauce of the sketch diamension and can explain it to others easily. Approach thoughts: I think that the tape on desk method kept the over thinking at bay, by making it as simple as possible, focusing on spacing and wall thickness first. You aren't really thinking in 3d or really a 2D much either. Once you got it spend the time to plot/ measure and size the rest of it (plinth, drain holes, tuyere, vents, etc.) Then when you have found all the mistakes, design flaws or design improvements, draft it!
I love your method! DRAW THINGS FULL SCALE. Makes a world of difference. I am just getting back into the metal world and am checking out everyone else's furnace builds AGAIN. A few things I've mentally taken away from other's is: 1: MEASURE your stuff. Make sure you not only measure your existing crucible, but the next size larger, and maybe TWO sizes larger. Who wants to stay with an 8, right?? 2: DRAW your stuff. Make cardboard full sized models. You don't want to use your real crucible as a model and fate pulls that gravity trick on you. 3: THINK it through multiple times. Make a cardboard model and practice with your tools. My tongs will be totally inadequate for a top-pull furnace at this time. 4: THINK again....and maybe a third time, but don't rush into it. You can correct some mistakes easily, I mean this is DIY, and we should have enough extra for patching anyway. Thanks again for some extra insights, and to let me know I'm not the only over-drawer/drafter.... Rob
Rob I can't agree more, there is a fine line of overthinking and idiot checking. Definately getting your ideas on paper is the best way to stop the latter, and giving it time is the best for former. Giving it time is certainly the best design method.
