New forge build, picking brains.

[John Leroy Brown]

Hey all, I’m at the starting phase of my actual build and wanted to have a thread to both document the process, and hopefully get feedback of the older and wiser, and hopefully get a few questions answered. Not only do I fully acknowledge my own ignorance/inexperience, but I also appreciate constructive feedback (I.e. … I get that some of my ideas may be misguided, but I’d appreciate an explanation or link that explains why/how I’m wrong or what I need to reconsider).

Starting off, I believe I have all the materials needed with the exception of a few components for my new burner system. I’m wanting to build a two piece shell-D shape(figure it’ll make repair’s easier if I’m just having to replace the floor). My shell is a piece of old line pipe that is approx .375”-.38” thick, with an ID of approx 15 5/8”-16” and is 25” long. I’ve already split the seam on the pipe (be careful cutting anything under pressure, whole thing shifted open an entire inch after cutting it, thankfully I wrapped it in chain) and I’m planning on straightening the bottom ends at it’s widest point (approximately 16” widest). From the floor (which will be formed and cast as it’s own separate piece) it should have inner dimensions of around 16” wide at its base, 20” floor to ceiling (this is the one dimension that I have the most concern about, that I may want to keep it a bit lower), and 25” deep (which could easily be shortened). The floor, doors and anything else will be made from a sheet of .2” thick plate, 33”  by 60”. Please remember those inner measurements do not include the 2+” of kaowool or refractory.

As far as insulation goes I have 12 and a half feet of 2” #8 kaowool (I’ve heard it’s better to do two separate layers of 1”, if there’s truth there I can make that happen) and I have rigidizer. I also have 220 lbs (4 55lb bags) of mizzou castable plus, and a dozen or so rutland 2700* hard firebrick. I haven’t settled on a refractory coating yet, but I figure I still have time on that one.

Ok, so time for the questions. I’m not strictly planning on just knife forging (honestly it’s the lower end of my interests) and am hoping to do larger work (gates and hardware, possibly more sculpture work, axes and other tools). That being said I do worry about building something with a ton of space that I won’t need, and wasting that fuel.

So I’m wanting to know if, first, my forge area seems to big. Second, depending on my work area/volume, what’s the formula I want to figure out how thick my refractory coating needs to be (any positives or negatives on thicker vs thinner is appreciated). Lastly I’d like to know what formula/considerations I need to look at to build a burner (I’d prefer doing a ribbon burner but I’m sure Frosty might have something to say that may sway me) given the approximate volume I’m looking at. 
 

Thank you for your time and feedback, pictures included are of the shell and cutting process (was a bit of a pucker moment while cutting it and listening to it groan/shift), and sketched plans.

 

Lastly, I apologize for any shortsightedness in my posting or posting etiquette… I’m having issues with my home network (I think I dropped a driver) and am doing this on my cell. 

[George N. M.]

I'm not expert on the construction of propane forges.  I'm more of a plug and play guy.  But that appears to be a pretty large forge and is likely to be VERY propane thirsty.  You will need a large tank, probably an 80 or 100 pounder to feed it and to avoid freeze up of the tank.  Don't forget you can only forge about 4-6" at a time by hand.  Heating more than that much metal is wasteful of fuel and can decarburize the steel.  I suggest that you consider what you are likely to be forging and how big a forge you really need.

"By hammer and hand all arts do stand."

 

[John Leroy Brown]

I appreciate the response George. That pretty much encompasses my major concerns as well, I think a large amount of that can be Mitigated by two things though, cutting my working area depth (25” is a bit deep) and making sure my burner is properly matched to the work area/volume I have (which is part of why I’m looking at doing a ribbon burner).

I’d love to have a nice coke forge, but I’m in city limits and they already fine people about using their wood burning stoves in “bad air” conditions (which oddly tend to peak in cold weather when the stoves are mostly needed). They actually have enough budget that they’ll fly planes and drones to get on to people for it.

Regardless, we’re actively looking at places farther out of city limits so a nice coal/coke forge may be in my future soon.

[George N. M.]

As an old municipal attorney I can tell you that there are instances with air quality regulations where there are loop holes due to poor drafting.  I have seen ordinances which ban wood and coal burning on high pollution days but do not mention charcoal or coke.  The more inclusive phrase "solid fuel" covers all the beses.  You might check the language of your local ordinance.

High pollution days are often in the winter because of inversions trapping the pollution near the ground.  The "Brown Cloud" on the Colorado Front Range is sometimes so thich it looks like you could get out and walk on it but if you get to a higher altitude the air is perfectly clear.  The same situation occurs in the Salt Lake Valley in Utah.

"By hammer and hand all arts do stand."