Talk to me about ventilation systems

[geargnasher]

I'm looking for some sort of multi-speed blower, probably in the 1,000 max cfm range, that I can install in my attic and duct to a fume hood over my casting bench, and also duct through the roof. Some sort of in-line unit or something I could modify to work like that.

The objective is to not have to listen to it hum, since I'll also use it for general ventilation in the room as well as casting. Any ideas on something I could rig up for 6" galvanized sheet metal pipe?

Gear

[OneSkinnyMass]

Not too sure if ya can get 1000 cfm's thru a 6" without a lot of noise, I'd look at 8 or 10" for that kind of volume. just a thought.

[geargnasher]

That volume number is just a SWAG based on puny 300 cfm fart fans and the 500 cfm blower in my microwave/convection/vent hood that sounds like a jet taking off and is barely enough volume for the kitchen range. I don't mind the sound of whooshing air, but the blowers themselves need to be elsewhere, preferably 20 feet away in an R-30 insulated attic.

Gear

[Canuck Bob]

We have kitchen and bathroom fans that are designed for attic installation for no noise in our newer designed insulated homes. Would they work?

[Bad Water Bill]

Can I become your house heat provider?:kidding:

[Calamity Jake]

Take a look on the Graingers web sight they handle all kinds of blowers for venting about anything.

[cajun shooter]

You may want to look at the fans made to exhaust the hot air from attics and sold at all building supplies. I have a 12x24 building that was intended for my tools and casting but my wife has a good share of it now.
I cut a hole in the side of the building over my bench area that fits a attic fan. These fans are made in different sizes and are thermostat controlled. Mine has a adjustable thermostat so when it is colder I may turn it on by adjusting the on temperature down. You could also just wire it to a light switch.
I also have a 30 inch shop fan that blows from the rear towards my bench and the exhaust fan. No fumes come my way even when I flux.
The attic fans are less than $60 complete with outside trim included.
A hood lets all the fumes come over you before being vented; something to think about. Later David

[schutzen]

I have not to brought this idea to life yet, but I was considering getting a large (42inch) kitchen exhaust hood and extending the sides to make a fume hood. If the sides and rear are dropped down to your table top, you should be able to close in enough of the front to create a good draft and still be able to work. If the noise of an exhaust hood is too much, consider removing the fan and filters. Then at the far end of your exhaust pipe install a duct booster fan on a switched at the hood. The last duct booster fan I bought was less than $30.

[dragonrider]

I think 1000 cfm is a whole lot more than you need. I'll bet this would do what you what easily.
http://www.northerntool.com/shop/tools/product_200321023_200321023

[midnight]

I believe what I am using is a squirrel cage fan I bought at a rummage sale for $10. I think it is a furnace fan and I don't know its CFM but its plenty. It sits right above my casting hood and I can't even hear it run. I used 6in stove pipe from the hood to the fan. It then goes outdoors through a 4in drier vent. It works great for me and is very quiet. Those of you who know a lot about duct work and moving air will probably tell me all the things I did wrong but it really works. I'll try to post a couple pics.

Bob

[725]

schutzen,
I have done exactly what you described. Yard sale kitchen hood ($2), scrap sheet metal pop rivited to form sides and a back. Two speed fan and even a light. Flexible hose to an outside vented area. Little noisy but not objectionable. My vast scientific knowledge and expertise tells me it must be working as visable smoke/fumes seem to follow out in the direction of the fan and blood lead tests show I am very low. One thing I did was to keep the height of the unit as low as possible and still be able to cast without issue. That's with my bottom pour. I still do most of my laddle casting outside.

[geargnasher]

Thanks for all the replies everybody!


We have kitchen and bathroom fans that are designed for attic installation for no noise in our newer designed insulated homes. Would they work? Sounds like what I'm after, but I've never seen one. A remote, in-line blower unit would be perfect.


Can I become your house heat provider?:kidding: It's a 140-square foot room with 8' ceilings and an outside fresh air duct, so it won't take away from the home heat. Might have to stop casting in just my skivvies in the wintertime, though!


Take a look on the Graingers web sight they handle all kinds of blowers for venting about anything. I know, as do about a dozen other major warehouse sites. Problem is I don't know what to look for exactly, and am asking those with direct experience with whether something works or not.


I think 1000 cfm is a whole lot more than you need. I'll bet this would do what you what easily.
http://www.northerntool.com/shop/tools/product_200321023_200321023

I'm thinking you're right about that. If I build a fume hood, 150 cfm ought to be enough to remove fluxing smoke. I'll see what I can come up with, you all have given me more ideas.

Gear

[Mk42gunner]

Might have to stop casting in just my skivvies in the wintertime, though!

Yet another mental picture that I did not need.

Luckily I hadn't taken a drink from the fresh cup of coffee yet.

Robert

[Bad Water Bill]

[QUOTE=geargnasher;152



It's a 140-square foot room with 8' ceilings and an outside fresh air duct, so it won't take away from the home heat. Might have to stop casting in just my skivvies in the wintertime, though!
Gear[/QUOTE]

So now you are trying to keep me awake at night with the terrifying picture of you casting in your skivvies.

Just the thought of that picture would keep the bravest here awake all night.

It's a 140-square foot room with 8' ceilings =1120 cubic ft. Yes you could get COLD even in southern Texas with that amount of cool air blowing past your scantily clad posterior every minute.

How do you intend keeping your mould warm enough to cast any kind of boolit? Them boolits will be shivering as they drop from the ice cold wind blown mould.

NO pictures PLEASE. My old heart could not take the shock.:kidding::kidding:

[btroj]

I don't think home hearing is a problem Gear generally faces.
I would rather be his electric company when he runs that and the AC in the summer!

Other than that I have nothing to add. This is way outside of my area of knowledge. Good luck Gear.

[geargnasher]

+1 Brad, I rarely consider the cold when building, mainly the hot. My biggest concern is summertime casting in this new room, when I'll be sucking copious amounts of hot wind from the hell-blasted scorching outdoors into my gun room. That's why a multi-speed exhaust system is essential.

Sorry for the mental scarring there, fellas! A man's gotta do what a man's gotta do when it's 110 in the shop and boolits are needed....
:bigsmyl2:
Gear

[Bad Water Bill]

Well to turn a light bulb on. You cast when the desert heat is DOWN and go to the range and shoot when it is just light enough to see the targets. The rest of the time is for those brown bottles of liquid replenishment.:bigsmyl2:

I just hope that none of the noobs see your posts and try casting your way.

Oh that is right you were referring to fly casting.

[geargnasher]

Unfortunately, this isn't the desert, either. I've smelted lead outside at midnight or later and the temps sometimes are still in the upper 90s. Evaporative coolers are useless due to the humidity. But I love it here, really I do!

Gear

[tcbnick]

I really don't mean to Hyjack here, but I was wondering about the temp of the exhaust in the flue and at the point of exiting the shed? should you use double wall pipe or would single be ok? Or maybe a better question would be, can you run it out just like a dryer vent. Sorry about the New ? but thought it might tie in with a hood vent design

Thanks Nick

[Bad Water Bill]

The exhaust air will virtually be the temp of the room. You are only trying to get rid of the smoke mixed with the air you are standing in.

[chambers]

Here are several things to consider: install hood over lead area( close capture of lead fumes), exhaust/duct outside, 1000 cfm is standard furnace blower rated at about 1/2" external static - 1/3 hp to 1/2 hp, most are multispeed( 3 or 4 speeds) and need to just manually move wires to different terminals and allows use to adjust to airflow needed, 1000 cfm will be 10"to 12" diameter pipe depending on lenght of run.

[geargnasher]

Thanks Chambers. I have a furnace blower, and studied the wires and figured I could make it multi-speed with a gang of single-pole switches in parallel. I was planning on using it for a wood shop ventilation fan. So if THAT's what 1K cfm is like, that's WAY too much! You just barely spin the centrifuge with a finger and it starts pushing air.

Gear

[geargnasher]

I think I found one, anybody have any experience with these? http://www.rewci.com/fa6257cfminc.html

Gear

[cajun shooter]

Gear if you look at the fan you are showing it only is rated to move 303 CFM which is very low. If you look on that same site in the left column you will see attic fans.
That is what I've used for years. You just cut your proper size hole and mount the fan. They sell louver vents that go on the outside. The attic fan is rated at 1300 CFM and will do 4 times the job of the other fan vent. Plus it only sells for $59.95 complete minus the outside vent which is made of a plastic type of polymer and they are cheap. The bonus for this type of fan is that it maybe used in the summer to keep your storage building or garage much cooler by allowing it to run.
Here in Louisiana where the humidity is so thick it can be sliced with a knife it will help preserve the items in that building.

[bobthenailer]

They make a booster fan that you can install in / between exsisting round duct work at any location to boost air flow to any room in the house . perhaps this would work for your project ?

[shaune509]

1000cfm would replace ALL the air in thatroom every 68 seconds, would most likly need an open freeflow inlet of 24"x24" for makeup air. 300cfm with near direct hood to pot area would be more than suffciant. remote duct fans lower most noise, caged fans quiter than axial blade type, verible speed switch allows for adjustment to needs.
shaune509

[atr]

I cast outdoors,,,natural ventilation

[geargnasher]

1000cfm would replace ALL the air in thatroom every 68 seconds, would most likly need an open freeflow inlet of 24"x24" for makeup air. 300cfm with near direct hood to pot area would be more than suffciant. remote duct fans lower most noise, caged fans quiter than axial blade type, verible speed switch allows for adjustment to needs.
shaune509

That's what I'm discovering about my original guesstimate of 1,000 cfm, I might as well just leave the door to the gun room open and open the front door of the house! I'm not very familiar with HVAC stuff, and didn't have a very good concept of air flow, so that's why I asked. I'm thinking the 300-ish cfm inline fan will do fine as long as it can suck through 10 feet of pipe and blow through another 10 feet. Not sure how much loss there will be, but probably negligible.

Gear

[btroj]

Have a couple politicians stand on either side of your house. Between the hot air they blow out and the way much of what they do sucks you will have plenty of air flow!

[leadman]

When my BLL had risen I built my "casting closet". It was basically a bench with 3 sides with a 20" box fan on the side opposite of where I stand. It was secured about 1 1/2" feet above the top of the bench. I had 2 pots and a shotmaker in the enclosure.
What I found is a fan behind me disturbed the air flow going towards the 20" fan and swirled around the front of me. So I only used the 20" fan and it worked great.
I would recommend you have your suction opposite you where the top of your enclosure meets the side. This way it will draw away from you.
You can build a cardboard enclosure to test where you should place the pipe(s) in your enclosure so you get it right the first time.

I had also tested for lead on the surfaces (including me) with the same kit that Home Depot sells. Has the vials with swabs and liquid in them. Crush part of the vial to release the liquid. Look the same as some in first aid kits. This is how I determined the fan behind me was causing problems.

[Jammer Six]

Speaking as a former general contractor, I don't know the answers to your questions.

What I do know is that it's a basic HVAC problem. (Since I hate jargon and abbreviations, "HVAC" stands for "Heating, Ventilation and Air Conditioning".)

There aren't very many secrets left to it. It's been researched, plotted, graphed, bought and sold for several decades.

The size of the blower, the position of the blower, the size of the pipe, the pipe material, the number and degree of bends in the pipe all matter, as well as the level of protection you want.

The worst case would be if you spent the money, flipped the switch, and were still breathing something you thought you'd dealt with.

Dust collectors, paint booths, welding booths, mechanic's shops, to name a few, have all dealt with a similar problem, and they're pretty good at doing it economically.

I'd start googling with "HVAC", "Lead fumes" and "ventilation".

Good luck!

[jsizemore]

Most of the Jenn-air down draft fans I've installed are 500-600cfm. They are remote located and work well enough to eliminate cooking odors. I've got a couple of these from replacement jobs for free. The ones from the freestanding ranges are adaptable for mounting and with a variable speed control will work for your casting room.