Belgradearmourer Posted February 9, 2011 Share Posted February 9, 2011 As I've been lurking here for a while, I think I have exhausted the search function regarding smokestack construction, so it is time for some questions. I plan to use a solid fuel forge, for armouring, due to availability of free hardwood in the near proximity of my new shop. I plan to use design similar to this one: http://twinoaksforge.com/BLADSMITHING/MAKING%20CHARCOAL.htm cutting and using an old ~80-100 liter boiler instead of the 55gal. drum. Now, the forge. As I understand, a 10-12" square or round smokestack, rising about 4' above the rooftop should do the trick. It will have a total height (hood included) of about 13-14'. As I will be heating sheet metal up to 2' across I can not use a side draft forge hood. The stack is planned to be braced to the wall of the building and to go straight up through the roof. I will probably make the smokestack 12"x12" due to the ease of construction. For the hood and lower segments of the stack I plan to use .5mm (~25ga or .209'') mild steel, and for the upper sections (near and above the roof) galvanized steel of similar thickness. I thought that the hood should be about 20"-24" above the firepot, so large breastplates could be heated with no problems, but this page http://www.beautifuliron.com/chimneys.htm says that 18" is optimal. Is 24" too high? Would pop-rivets be strong enough to connect stack sections to each other securely enough and to make the joints sufficiently airtight or should they be brazed as well? What would be the appropriate rivet spacing? If braced to the wall and made in 3'4'' sections would the intended sheet be strong enough? How steep the side panels of the hood should be? Should I avoid at all costs making below-the-roof sections out of zinc-galvanized steel and go for mild, or is top 2-3' OK? I have not used such thin steel so far, so that is why I am asking these questions. Oh, and I have not yet decided on which style of chimney cap to use. The conical one, or the pipe-over-pipe design, Quote Link to comment Share on other sites More sharing options...
Belgradearmourer Posted February 9, 2011 Author Share Posted February 9, 2011 And one more question: Is there any significant difference between these two top draft hood designs? I am inclined to build the variant A, due to the ease of construction, installation and the reduced amount of scrap that would allow me to put two side panels against the wall. Quote Link to comment Share on other sites More sharing options...
Marksnagel Posted February 11, 2011 Share Posted February 11, 2011 Welcome to IFI. I can't answer your question with any degree of expertise so I will let those with more knowledge and experience answer. I just wanted to welcome you. Glad you joined IFI, hang around, learn, share, teach and just know that you are welcome. Mark<>, Quote Link to comment Share on other sites More sharing options...
Belgradearmourer Posted February 13, 2011 Author Share Posted February 13, 2011 Thanks Marksnagel for at least posting something here. After 90+ views and no answers I think I'll have to take a stab in the dark and see if the design will work out OK and than report back. If not, I guess I'll have to forge outside until I make necessary changes to the chimney. I'll be buying sheet steel tomorrow. Quote Link to comment Share on other sites More sharing options...
Sam Salvati Posted February 13, 2011 Share Posted February 13, 2011 look at this forge: Quote Link to comment Share on other sites More sharing options...
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