Wolgerrex Posted October 2, 2019 Share Posted October 2, 2019 Hi all, after 2 years of reading on this forum I actually made an account. The main reason is, I have always been able to find all answers to questions just by searching and reading except for 1. For forge building the standard has been discussed and set a whole bunch of times, size, shape, angles, what linings to use, how thick, how to cure the linings, etc. The 1 area I seem to not be able to find much of any information on is the topic of burner to hole in forge, size/ratio. This question specifically relates to venture burners (T-Burner) in a standard forge of 2" Kaowool, Kastolite 30, and plistix. What is the correct ratio? what diameter hole size in the forge to the relationship of the burner/flare size, is there any considerations to the OD vs ID of the burner/flare. Please educate me on this, I feel totally clueless in this area of design for a gas forge. Quote Link to comment Share on other sites More sharing options...
Latticino Posted October 2, 2019 Share Posted October 2, 2019 Good question. A well designed naturally aspirated (ventauri) burner should not need to induce secondary air at the entrance of the forge. In that case the forge opening should be carefully sized to suit the particular burner. In my mind the best design will have a initial opening that the outside of the burner end fits closely into. Then there should be a slight narrowing of the opening diameter that will protect the front of the burner without obstructing it in any way, no more than the thickness of the burner end tube wall (Though I also have a stainless steel flame retention nozzle on my home forge). Then the opening should flare out in the standard 1 in 12 ratio to allow the fame to spread out and slow down as it enters the forge. To clarify, this lists the desired opening diameters from the exterior of the forge to the interior. Quote Link to comment Share on other sites More sharing options...
Mikey98118 Posted October 2, 2019 Share Posted October 2, 2019 You are asking the wrong question. Burners--especially naturally aspirated burners-- have very long turn-down ranges. Trying to come up with "the best" exhaust exit size for a highly variable flame is just plain silly!!! So, most builders find it convenient to deliberately make the main exhaust opening (at the front of the forge) deliberately oversized, and reduce the amount of exhaust with a variable brick wall, etc. There are many variations on that scheme. You can make an opening that will accommodate the largest flame your burner(s) can put out, but still be fairly small ( a 3" by 4" opening in a forge with a 3/4" burner, or two 1/2" burners in a five gallon forge), and hinge the front opening, so the occasional large object can be passed through. Obviously, no one is going to list their idea of the "best" opening size for every forge out there... Quote Link to comment Share on other sites More sharing options...
Wolgerrex Posted October 2, 2019 Author Share Posted October 2, 2019 Sorry Mikey, I didn’t word my question all that well. I was trying to ask about the hole in the forge where the burner it self enters into the forge. Latticino, cool thank you. My last forge I did a step opening like what your explaining but it was sharp not gradual. The first inch was the diameter of the O.D of the flare. Then I made a sharp step the the burner could rest on like a ledge. The rest of the holes diameter was a hair smaller than the I.D of the flare. It actually worked better than any other forge burner hole I had made (straight same size as the O.D of the burner) But I just came across the shape accidentally due to experimenting. The forge was 181 cubic inches, a 1/2 burner just didn’t seem enough so I opened the beginning of the hole (outer most of forger) to fit a 3/4 burner and surprisingly it worked pretty good even down to 2psi. Again not knowing what I was doing I had to many variables to know why it seemed better. I’ll try your advice! Quote Link to comment Share on other sites More sharing options...
Frosty Posted October 2, 2019 Share Posted October 2, 2019 Welcome aboard Wolgerex, glad you delurked. If you'll put your general location in the header you'll discover how many members live within visiting distance. The hole you're referring to is what I've been calling the "Burner Port." Meaning the opening in the forge for the burner in the same sense the burner has "intake ports" to draw intake air through. What you describe sounds like it's working well for you. I shaped the Kaowool with rigidizer and later Kastolite into a flare shape. This lets me use a floor flange and just stand the burners on top of the forge shell. I don't put flares on my burners, I screw a steel thread protector on the end to make them easy to mount. Welding thread protectors into the plenums of the ribbon burners lets me experiment with different burners. Turned out the ribbon burner made all the Ts I tried in them much more stable. The large rectangular hole the ribbon burner mounts in on that forge is the Burner Port. Make sense? Frosty The Lucky. Quote Link to comment Share on other sites More sharing options...
Irondragon Forge ClayWorks Posted October 3, 2019 Share Posted October 3, 2019 Welcome aboard, like Frosty said, if you edit your profile to show your location, we won't dun ya for it when answers require knowing where in the world you are located. Don't know if you have seen this yet but it will explain a lot of the idiosyncrasies of the forum. READ THIS FIRST Quote Link to comment Share on other sites More sharing options...
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