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OK folks, I'm needing to vent my forge(s) in the shop and can't puncture the roof to do so (aluminum shingles that took me a long time to do and serious $$$$$). My questions are regarding the feasibility and functionality of power draft systems.  

 

Here's a pic of an old commercial forge with a nice downdraft system that I am thinking of building a version of. Since the exhaust from our forges aren't all that hot, I would think a simple 6-8" duct with a booster fan should be sufficient, but I would rather lean on the experience of those before me.

 

  I have coal, charcoal and propane forges, all of which I use outdoors until now. The shop is 40' x 50' if it matters. It will be fully insulated and finished in the near future but has plenty of natural air infiltration at this time.  I also have a 14" powered vent fan with elec louvers that can be used for the system but MAN that thing pulls the air !  It would evecuate all the heat in 30 min during the winter.

 

 I like the setup that Gote is using http://www.iforgeiron.com/topic/41796-flashing-around-the-chimney/ but want to possible modify it by running the pipe lower and using a different style of "induction"

IMG_20151201_162633332_HDR.jpg

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  Sadly, that idea is a bit too permanent for my use, at least inside my current shop.  Long story short..... I built it and use it as a mechanics garage complete with hoist. It currently houses 3 of my 4 muscle cars all in varying stages of restoration and until all are completed, it will continue as a mechanics shop.  My biggest issue is that I also do quite a bit of fab/welding and now Smithing all of which really require it's own shop but alas, I am maxed out on allowable sq ft of building space per the township. That and money/time seem to be elusive for such nicities. 

 

   I'm thinking more along the lines of a dust collection system for woodworking. A main branch with "taps" to each piece of equipment.  My idea would be a small single wall penetration with the ability to moderate the position of the hood to suit the forge(s) being used at the time. Say by using a thin steel hood on a stand with a piece of flexible pipe to connect to the main line. That would allow the forges to be moved around to better find an optimal position, or if available real-estate becomes tight.

 

  BTW, If anyone has plans for a hood similar to the Buffalo in the photo, that would be great. So would the actual forge. I'd buy one of them !

 

  

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Run ducting along the wall with Ts where you want a positive vent. You can cap the ones not in use and connect to those you want to vent with flex ducting. Then hook it up to a good blower outdoors after running through a cyclonic separator.

Frosty The Lucky.

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He said "cyclonic seperator....". Heh heh..

 

That's pretty much what I was thinking, although why would I need a seperator ? I can't imagine that much particulate or heat but that's why I'm asking.  Also, I would prefer to have said blower inside rather than out. I can live with extra noise, just don't want the hassle or weatherproofing and visual.  I have a perfect unused attic space that would hide all of it.

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You'll be amazed how much particulate crud it'll pick up. I much prefer a cyclonic to a typical dust comp filter bag. We're dealing with metal and metal dust can be extraordinarily flammable and if you're exhausting smoke it's even worse. Smoke is unburned material and only a small % is non-flammable mineral. 

Some years ago a knife maker almost burned his shop down TWICE. He'd sand his handles and the dust comp cleaned the dust out wonderfully well. Then he'd change belts and start grinding the next knife blank it didn't take long for enough wood dust to build up in the hoses to come into range of sparks while they were still hot. If his insurance agent hadn't insisted on an exterior installation he'd have lost his shop first time. The second time I think his insurance agent shut him down as too dull to use power tools safely.

Finely divided anything is a hazard and I prefer keeping it out of my shop. You also want the blower AFTER the filter whatever it is.

Frosty The Lucky.

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  You make a very good point. I know about the flammability of fine particles, just didn't think of it that deeply in our craft. Flour cannons are fun ! (nothing else that stuff is good for)  How about this ?..... no dust collector and put the blower at the end with a nice polished 6" tailpipe and spark plug ignitor !  Can you tell I'm a RatRod guy ?

 

  Now to look up DIY Cyclonic filter plans and find a sealed motor.

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Do you have an electric fuel pump with the jet in your tail pipe? One button injected a bit of motor oil right behind the header so the pipe blew blue smoke. A good way to get the dip stick in the jacked up pickup truck who likes to stop right on your bumper and won't dim the head lights. Just a quick cloud of smoke evidently coming out from their hood usually has them looking under the hood for a while.

A little squirt of gas and a spark makes for another entertaining tailgater mitigating affect.

No, I haven't looked into cyclonic separators. I never finished my down draft exhaust system in my shop  and just use the gozintas. The accident pretty much put the kabosh on finishing my shop.

You might look at some of the cyclonic vacuums on the market. I think we'd all appreciate it if you posted what you find here.

Frosty The Lucky.

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   None of my current cars are on the road, so no to all the above. :(  (66 BelvedereII, 69 Karman Ghia, 72 Duster, 74 'Cuda)  But that's a totally different discussion which I can type all night about

 

  Not sure about the "accident" nor is it my business to ask, but I hope all is well.

 

  I will most definitely post the whole shebang once I get it to some semblance of doneness and in service.

 

            Todd

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I was attacked by a great white. . . . birch. The whole story is in the Prayer section here. I was cutting fire wood and the tree kicked back almost killing me on the spot. I'm a TBI survivor and living proof prayer works.

Frosty The Lucky.

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  • 1 month later...

it said they were in a high school class- mybe a shop class

                                                                                                       Littleblacksmith

 

quick question, where does all of the smoke go- I mean theirs no pipe going up out the roop

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meant to say roof-think yall knew what I meant. this isnt gano make any sense 'cause its going to merge my posts.

                                                                                   Littleblacksmith

never mind it didnt

 

 

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  • 3 months later...
  • 5 months later...

Ok, so I just got back to this one.  That Buffalo setup uses an underfloor vacuum system of sorts. basically they all sit atop a pipe like the sewer pipe in a slab which is then connected to a vacuum/blower outside.  this is what got me thinking of a vacuum type evac system instead of draft.  

As it is, I am now working on an overhead version of this. I am using the housing and impeller from an old walk behind leaf blower. no need for a ton of RPM to draw the smoke away which and no need for a filter to protect the works. This is where I'm currently pondering life, ........ I need a LOW rpm electric motor, or to find a cheap but safe way to dial down the speed of a regular one. the other thought is instead of direct drive, use a jackshaft with pulleys and belts, but that becomes too complex and costly. the HP requirement will be very low since the speed will be slow and the fan is pretty well balanced.

  Thoughts ????? 

    Todd

20161112_211027_resized.jpg

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not a bad idea.  I'm concerned about the radial load and lack of actual bearings though. that impeller weighs at least 15#

I keep thinking a jackshaft on pillow block bearings is the best way. 

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With it weighing that much you might want to consider making friends with some guys from an A/C repair place and see if you can get an old blower from a furnace they took out of somewhere. The one I know has a collection of old functional parts he keeps from where people wanted to replace/upgrade the unit. If he goes to a job that needs one of the old parts he has he gives the option of using it (for a significant savings and warns the people that he can guarantee it'll last) or they can get a new part. He has a pile of old blowers laying around. Truth is I need to talk to him about getting one for my shop. :) 

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Thinking more on Michael's suggestion, I've got an older ceiling fan that I can't give away. I'll do some "testing" on how much torque it has. That might be just the ticket, add a jack shaft and a few pulleys to get a variable low speed setup.

More to come, with pics !   Cause I know everyone loves pics !

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Use it as it but use it as an extractor. Then you do not get the hot gasses in the wheel. You can also vary the suction by changing how much external air the contraption will suck. In principle you end the horizontal pipe with a tee. One end goes up over roof and you blow into the other with some kind of deflector or funnel.

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I don't follow you on the "extractor" part. I figured that's what it was.

It will be placed about 16 linear feet from the forge (10' section of horizontal pipe and 6' down from ceiling)  Also, the fan wheel is made from 5/16" plate and the housing is ~12ga. so I'm not at all concerned about heat. the motor is externally mounted from the housing/impeller.  

 

91013 pics 014.JPG

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