Jump to content
I Forge Iron

Exhaust advice.

Recommended Posts

After numerous abortive attempts at creating an exhaust hood that will allow me to forge in my garage without killing myself due to smoke inhalation. I've McGyvered together a 1hp blower and some 4" exhaust pipe to successfully vent all the smoke created by my coal (I don't know from grades of coal but I do know that it was free) fired forge with Keg-made hood.

It works a little too well though, as it tends to suck up sparks and the occasional small piece of hot clinker out and shoot it into my from yard. I solved the large particle problem by using a piece of fireplace screen over the intake. But little sparks are still a problem.

Though I use coal for now I would like to have a charcoal option because of the smoke issues, I can't because the sparks look like an amateur pyrotechnics display.

All of this is to ask; does anyone have a suggestion on how to stop this while maintaining a sufficient airflow to keep my work space smoke free? I'm sure I'm missing an obvious fix somewhere and just as sure that you good folks can point it out to me. Thanks for the help.

Link to comment
Share on other sites

Have you looked at the plans for a side drawn stack? They seem to work really well in the pictures I've seen and the testimant I've heard. I have personally used a few set ups that have adjustable stacks, say 6-8 inches or more in diameter, that can be pulled down close over the firepot. These adjustable stacks feed into a bigger hood further above. They also seem to work well, but I have seen them fill the shop with smoke too if they are not tended as well. Personally I like the design that is demonstrated in photos of Hofi's shop. He has a side draft, that has a square tube going back through the wall, then round stack that goes up the side of the building along the outside.

Link to comment
Share on other sites

I use a side draft I cobbled together. Works well with a 8" triple wall flue, but really needs about 10+.
There are several planson the net. The smoke shelf reffered to in some is not needed in my opinion, and mine does not have one.

Charcoal emits no less dangerous smoke, you just can't see it as easy. Think Carbon Momoxide.

Link to comment
Share on other sites

ACR NGG16A 141 & 155

how much spark arrestor overkill you actually require however....
but it has all been done before, alot of it in RR
there are of course many way to approach it, from nozzels and baffles with screens as illustrated, to cyclone knockout pots and wetscrubbers (air pollution devices)
to as mentioned designs with less uptake

trick would be working with what you have and starting with what youve already done, some approaches might offer additional benefit (neighbors nearby, ordinance Nazi's) Edited by Ice Czar
Link to comment
Share on other sites

What a coincidence!
I am also concerned about using my coal/coke and gas forges in my insulated shop.
I can open two man doors and two windows to allow fresh air in when I am using my gas forges.
But the HEAT is still a problem. It seems as though the air just mixes and is not clean air.
So I need something to help me remove the heat and products of combustion that is produced mostly from my gas forges.

I am making a side draft chimney similar to the Hofi side draft chimney BP1048 Side Draft Chimney for use to help clear out smoke and products of combustion when I use my coal/coke forge.
My main stack (12

Link to comment
Share on other sites

I have heard it said by some that we do not need a "smoke-shelf" in our flues, But have they tried to understand WHY they are used by so many of us?

The turbulence it creates breaks up the flow a little, and as a result of this, drops ash and sparks to the shelf. I have not had my side draft running very long, but I do not have any sparks leaving and I get a bit of fines to clean up from the bottom of the flue every time I use it, so it seems to be helping me.

Just a thought.

Link to comment
Share on other sites

So I need something to help me remove the heat

a large thermal mass and a heat exchanger

a steam boiler to run a power hammer would be nice :P
or a pile of rock to preheat your blown forge air, or transfer to water that you pump to a house, greenhouse, fishtank

oh no I have too much energy :p
Link to comment
Share on other sites

Uh Oh

(chalking up more karmic female debt) :D

in reality this is no different than cooling a computer, a car or a house

1. a heat sink, something that will absorb a large amount of heat quickly and is also relatively immune to the temperature (and corrosion) it needs to withstand. Ideally isolated from your workspace, accessible to clean as needed.

2. a means to transfer that energy to somewhere that benefits you, since liquids have approximately 40 times the density of gases, and water especially has good thermal transfer capabilities while being plentiful and benign, a natural choice.

3. a use, distributed heat is good in winter, good for hot showers year round, good for other hot processes (recuperators, preheaters)
Converting heat to kinetic energy is a bit trickier. Steam, Sterling engines, {so called) Thermal Hydraulic engines, Cogeneration, Trigeneration, combined cycle.

this little downward blip in fuel prices isnt going to last, and few claim to have too much money :P

start with trying to get her to let you build a forge powered Absorption refrigerator so you can have wild drinking parties in the workshed, then a steam boiler, after you wear her down with those, start getting practical :p

Edited by Ice Czar
Link to comment
Share on other sites

Lot's of workable ideas here and I'm not suprised one bit.

The charcoal option is for my neighbors and since I heat 100% with wood I can have a ready supply of charcoal just by sifting my fireplace ashes and much more if I purposely set out to make charcoal. I appreciate your concern though.

Chaos, an ajustable stack? Is this something suspended from above?

I liked the look and what I suppose would be the improved utility of the side draft forge and believe that I have sufficient airflow for it to work. I actually did move the hood to the side of the firepot just to see if it would draw the air and it seemed to work well. The only (admittidly juvenille) reason I haven't built it that way more permanently is that I like having a keg for a hood and since I've already cut it to the purpose... I suppose I could just turn it into fireplace shovels or flowers or something though...

Ice, nice pics. That's kind of what I was trying to get done with the fireplace screen. I reckon I could afford to put a couple more in-line and still retain sufficient airflow to keep me out of the dark sulphorous clouds.

Steve, thanks for the clarification on the smoke-shelf. I'll have to research some plans for a good side-draft hood for future implementation.

I used to think that forges were built but I've come to realize in the short month or so of my operation that they are instead evolved. I'll take some pictures so you guys can laugh at my set-up. I have to have it indoors because (even though every house in my neighborhood has at least one fireplace) apparently even the sight of a woodpile is offensive to some of my neighbors. I'm a Stealth-Smith! Maybe that's what I'll name the forge. Stealth Smith Forge. What do you think?

Edited by Strongback
Link to comment
Share on other sites

(even though ever house in my neighborhood has at least one fireplace) apparently even the sight of a woodpiles is offensive to some of my neighbors. I'm a Stealth-Smith! Maybe that's what I'll name the forge. Stealth Smith Forge. What do you think?

I like it
(Im a stealth smith as well, I'll post pics too in say a week)

hood uptake location would be a good start ;)
Id also experiment a little with simple baffles, making the air flow slightly different so particles smack into this that or each other is pretty much what all those nozzles and channels are about (as is the shelf mentioned)

you might also want to research various cowls in the event you have issues during a blow
youd have a head start Edited by Ice Czar
Link to comment
Share on other sites

Strongback; or is it --> AKA Stealth Smith Forge.
It has a nice ring to it.
A lot of us have the same problem with location and would do well to give our operations the code name "Stealth Smith Forge"
Stealth Blacksmithing is the art of making your blacksmith operation appear as though you have a well equipped Barbeque station.
If you can convince the neighbors that it is a Barbeque station, you have passed the "Stealth Blacksmithing Test".
Ted Throckmorton

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Create New...