super sucker side draft with a side exit stove pipe

[robodog]

Newbie here. I just inherited an entire blacksmith shop and I'm about to set up the chimney. The shop is in an old horse stall in my barn. The chimney will be stovepipe that will enter through a cinder block wall. I'm thinking about building the super sucker side draft that I've seen plans for. So, here's my question: Rather than have the stovepipe go out the top of the super sucker side draft (SSSD), I am thinking of having it come out the back of the SSSD. From there it would go straight out through the wall and then take a 90 degree turn up.

Comments? Suggestions? Advice?

Thanks, Roger

[Glenn]

Do a site search for Hofi's through the wall chimney.

One thing about those old barns, make sure everything that can burn has been removed from your forging area. Create some walls or half walls that seal to the floor to keep any hot stuff contained in your area. Grinding sparks can travel 20 feet or more and that red hot piece of metal that you just cut off on the hot cut can skip, bounce, and hide in some inaccessible places.Keep a 5 gallon bucket of water handy so you can put out any fires while they are still small

[Harley]

IN addition to a 5 gal. bucket of water I would suggest a large fire extinguisher kept in a easilly accessable place. I have had two or three small fires start from grinder sparks and or welding and believe me fire can spread very rapidly (don't ask me how I know this). An old horse barn or stall is a tinder box waiting for an ignition source. in the attached photo , note the fire extinguisher on the wall at the end of the welding table. You can't imagine how bad it feels to say " I should have had a fire extinguisher "
Harley

[robodog]

Glenn and Harley,

Thanks very much. I've searched the site and searched the web and have not been able to find anything like a "blueprint" for the Hofi. The two images that Glenn attached are very helpful and they look like exactly what I would like to build. I think that those images and the plans for the super-sucker, can be used in conjunction to build it, but I would love to see actual plans - if anybody knows where to find them. I've also read the full page at http://www.beautifuliron.com/chimneys.htm. That's full of good advice.

All warnings about sparks - heeded. Thanks. I do have stone walls and concrete floors, but will purchase a good fire extinguisher before my first fire.

Roger

[robodog]

Another thing that has just crossed my mind...

Designs say that the opening should be nominally smaller than the opening of the flue pipe. Designs also say that the super-sucker is 13" x 13". That equals 169 square inches of area. A 10" pipe has an area of 78.5 square inches, and a 12" pipe has an area of 113 square inches.

Does the (smaller opening) advice refer to the opening at the smoke shelf? Does the smoke shelf actually restrict the opening or does it just direct the smoke?

TIA

[petere76]

Robo,

Both the Hofi and the super-sucker designs are essentialy straight pipes with full dimension transitions (elbows) . The smoke shelf venturi arrangement seen in old chimneys is a different design.

I made a modified super-sucker design around a 10 inch pipe system, it works very well. Simply scale the opening to accomodate the square inch relationship of the uptake piping. Because I operate in a cold climate I fabricated the opening so it can be covered. In the testing, I experimented a bit by reducing the opening and it does increase draft with a smaller opening. However, volumetricaly you get short changed on the smaller opening. The density of coal smoke (heavy) and the introduction of additional local air will quickly convince you to keep the opening as wide as possible. Once these stack configurations are heated up they draw very efficently. Uptakes are mass flow devices. Once heated the gas develops its own force (suction) via acceleration ( F=MA). Just fire up a piece of paper in the stack opening before you start the forge and it will work very well. Good luck.

Peter

[Dean Christman]

I think i saw in a thread that fireyfurnace. that his screen name had built a chimney like that. If you find him you could ask him

[Tradewater]

This must be a popular design, I'm building the same one myself. There is an absolute wealth of information on here, as well as a bunch of folks that have made all the discoveries and mistakes already...and will be glad to share. One thing that would help both of us would be a suggestion on the gauge of metal to use for the Hofi hood. I see that fieryfurnace used 3/16ths for his. Could a lighter gauge be used without any heat distortion problems? Not to hijack the thread, just wondering if a person could save a few bucks on the metal.

Randy

[robodog]

Randy, Here's a nice photo collection of a new Hofi hood being built and put to the test.

Roger

[Tradewater]

Thanks Roger, he did a heck of a job on his setup didn't he? That's the same basic layout of mine as well. He used some pretty thick stuff for the hood and I was wondering if you can get by with something thinner. Yes, I am a cheapskate.

Randy

[Frosty]

That's our Dave alright and that's how a Hofi style side draft hood ought to work. I think he used that heavy of gage steel because that's what he got a deal on. I typically use 14 ga. if it's going to need some structural strength and that's what I'd use for this type hood.

Of course in proper blacksmith tradition a good deal trumps specs so long as it's stronger than called for.

Frosty the Lucky.