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  #1  
Old 2009-08-04, 1:59am
ShellyJo1969 ShellyJo1969 is offline
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Default Range Vent Hood OR Glasscraft Vent????

Well, talked to hubby about the ventilation needs and he isn't thrilled with trying to make a barley box connect to the ducting, And trying to connect it, somehow to our existing vent fan 10 ft up on the wall.

He suggested getting a wall mounted stove vent hood and putting it above my work bench instead.

My question is: Will this work? Will this pull hard enough to suck the fumes away? OF course making some type of barley box is still a good idea no doubt, but will a hood work? If this is a viable option it would definately be easier to do that then to try to retrofit the already existing suction vent.

OK, I just checked some range hood prices and the ones that had 600-900 CFM's are over $650 HOLY CARP!!

IF that's the kind of prices that I'm facing I will either retrofit what i've got or probably just splurge and get one of those ready to go ones from glasscraft. Has anyone tried one of those and if you have, do you like it?

Michele
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  #2  
Old 2009-08-04, 3:46am
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The Glasscraft hoods are use a duct booster fan which is not really rated for the CFM that they claim when used alone. Most people who have them replace the fan with a much stronger fan.

An old range hood is a good starting point for a hood though. You need to make sure that it has a large enough vent connection 6-8 inches depending on your duct size requirements or you will need to do more retrofitting to cut a bigger hole. Also you will want to put a side and back on it anyway to contain the fumes better.

Check out Grainger for good blowers in the 600-900 CFM range. http://www.grainger.com/Grainger/cat.../hvacr/blowers

Also there are some good inline fans by FanTec and others that could work.

The fan will probably run in the $150 to $200 range new.
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  #3  
Old 2009-08-04, 3:57am
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I would go with the specialty ... this is toooooo important to cut corners on.....
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  #4  
Old 2009-08-04, 2:47pm
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The Glasscraft hood is a good size but the fan does tend to be a little underpowered. Kitchen hoods are usually a little small and underpowered, both. The power really becomes an issue with the distance the air has to travel to get outside. I use the Glasscraft hood with a blower that I bought from Grainger. It's a great combination and I use the original glasscraft booster fan to bring in makeup air under my work table.

Robert
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Old 2009-08-04, 5:03pm
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I have one like this, depending on your hood design, you might be able to use a smaller one:

http://www.dchydro.com/cgi/commerce....=action&key=81

Teague
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  #6  
Old 2009-08-04, 5:45pm
ShellyJo1969 ShellyJo1969 is offline
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I don't know anything at all about hooking up a range hood.

But there would be no distance either way, just gonna park my workbench right up against an outside wall and the vent system will go straight through the wall.

The Glasscraft hood looked easiest. It stated it was specifically for lampworking.
It looked like you just cut a hole in wall, fitted mechanism in and propped the suction part up on your tabletop or right above it, whatever, and it did it's thing.


I checked out the links but I still don't know how to use/install those in line blower things
??? http://www.dchydro.com/cgi/commerce....=action&key=81


Michele
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  #7  
Old 2009-08-04, 10:27pm
NMLinda NMLinda is offline
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The problem with the Glasscraft hood is that, as Paul Ewing and Richard Simmons says, the fan they install is more than a little inadequate. Most everyone who's posted about it rips out the fan and installs their own for that reason. Richard himself did a very nice retrofit and has posted some great pics. Like Paul's equally good vent system, Richard turned his Glasscraft hood into a barley box/fume hood by adding a back and sides.

Virtually every range hood you can get through places like Lowes and Home Depot is also inadequate for what most of us want or end up needing as a lampworking vent system. The only exception is a link Dale M once found to a really nice range hood that had a fan with ~900 cfm - seemed to fit typical lampworking needs very nicely. If you've found range hoods with 600-900 cfm, you might have seen it or something like it (If I can find the link, I'll come back and post it for you).

The RIGHT ventilation is not cheap. This subject comes up fairly regularly on LE. Every time I've seen this discussed, about the lowest folks can figure is $400 for a home-made vent hood like the barley box and higher for pre-fab equivalents. A cost of $650 for a pre-made range hood in the 600-900 cfm range is not unreasonable. Just to give you a comparison point, I recently spent about $450 for just the fan for my home-made barley box hood (it's 4' wide by 2' deep). The rest of the materials ran me about $100. I don't find spending that kind of money particularly easy in the current economy, but if I'm going to do lampworking, I refuse to compromise on quality and put my health at risk.

Puts me in the same camp as dpglassworks - you only get one set of lungs. Like the right eyewear (you only get one set of eyes, too....), ventilation is the last area you want to cut corners on. Another way to think of this is that $650 is far, far cheaper than your medical bills might be if you are sensitive to N0x fumes and the heavy metal exposure that comes from working with certain colors of glass, let alone the physical misery of exposure to these products. And there's almost know way to know if you're more sensitive than typical until it's too late.

I can absolutely appreciate that understanding how to select and build the right kind of ventilation system can feel overwelming initially. In that spirit, I can't stress enough how important and valuable it is for you to read and re-read (and re-read) the links folks gave you in some of your earlier posts, and spend an evening or two to go through past threads in this and other forums to see how folks build their systems. Seeing what others have built will give you the visual framework that will help the links make more sense.

The good news in your case is that your DH now seems willing to let you punch a hole in the wall for your hood - this makes life far, far easier for getting set up.

Linda
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  #8  
Old 2009-08-05, 5:37am
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errr..... That's Robert Simmons. Richard is the exercise guru. I'm the ventilation/glass fiend. We don't look alike at all.

Robert
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  #9  
Old 2009-08-05, 7:48am
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So far as I have been able to find this is the ONLY over the counter "range" hood" that even comes close to what you need for ventilation over a torch bench for reasonable price..... And remember these are the manufacturers specifications (the 900 CFM) and they may or may not be adequate for your application.... To improve the efficiency of the hood one can actually extend panels down from hood to form the "box" configuration that is more effective than the "generic" hood....

Here is main link page:

http://www.rangehoodsinc.com/

Here is sepcific hood:

http://www.rangehoodsinc.com/product...-Hood-3p50.htm

IF you decide that this hood may be for you, I would operate it without the "grease trap filters" as they restrict the air flow....

Dale
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Last edited by Dale M.; 2009-08-05 at 7:50am.
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  #10  
Old 2009-08-05, 8:33am
NMLinda NMLinda is offline
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Quote:
Originally Posted by RSimmons View Post
errr..... That's Robert Simmons. Richard is the exercise guru. I'm the ventilation/glass fiend. We don't look alike at all.

Robert


Oh, Robert, I'm so sorry!! I'd say Richard is hardly in your class. Teach me to post after my bedtime and not check what I'm typing!

My appologies!

Linda
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  #11  
Old 2009-08-05, 9:45am
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It's OK. It happens a lot, but I can promise that we are vastly different characters.

Robert
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  #12  
Old 2009-08-05, 9:54am
NMLinda NMLinda is offline
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I like the classy character you always bring to this forum!

Linda
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  #13  
Old 2009-08-05, 12:25pm
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Quote:
Originally Posted by Dale M. View Post
So far as I have been able to find this is the ONLY over the counter "range" hood" that even comes close to what you need for ventilation over a torch bench for reasonable price..... And remember these are the manufacturers specifications (the 900 CFM) and they may or may not be adequate for your application.... To improve the efficiency of the hood one can actually extend panels down from hood to form the "box" configuration that is more effective than the "generic" hood....

Here is main link page:

http://www.rangehoodsinc.com/

Here is sepcific hood:

http://www.rangehoodsinc.com/product...-Hood-3p50.htm

IF you decide that this hood may be for you, I would operate it without the "grease trap filters" as they restrict the air flow....

Dale
Good find, that is cheap for a hood of that capacity. If you are looking for a hood carcass, try looking for a used one and upgrading the fan, In my area there is a store called the re-store that's run by the Habitat for Humanity, and they have all kinds of used duct work & kitchen hoods.

The Glasscraft hood is not a good choice, I'm sure they are great people but that hood is lacking.


EDIT: I ran the numbers on that hood, and it's not possible to get 900 cfm with a 6" pipe as they claim the friction loss with 1 90deg elbow and say 6 foot run produces a friction loss of 1.07, and produces a 4586 fpm velocity, you would need a 10" pipe to achieve 900cfm.

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Last edited by JoeDeM; 2009-08-05 at 12:56pm.
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  #14  
Old 2009-08-05, 2:56pm
ShellyJo1969 ShellyJo1969 is offline
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Dale M. that hood looks great, and it's only $50 more than the glasscraft one.

*Is it as simple as mounting hood to the wall, cutting appropriate size vent hole straight through the wall, and sticking the cap/cover on the outside of wall? Does it come with everything needed for installation straight thorough the wall or do I have to buy ducting to go thorugh wall too?

Then I could get some sheet metal or something and put around back and sides for a barley box.

Would scap sheet metal like from a building project work? I think we have a few pieces of corrugated metal around her somewhere. Would that be adequate to form a barley box with the hood as the top part?

If I install this vent hood, couln't I take a long piece of metal and bend it in the proper spots to make a three sided shape and slide it under the hood and that'd be my barley box! That would work wouldn't it?
Please let me know! Everyone's help is invaluable! Some of my equipment has arrived and I"m so excited, my first torch is a mini cc, marvers, tweezers, gas regulators, flashback arrestors, hoses, my m15oxy generator is on it's way, My steel workbench is on it's way...I'm getting there! I have to get this hood stuff figured out and ordered and Oh! Maybe i should get my glass ordered right away! I'm really nervous and terribly excited all at the same time. I've never looked forward as much to any crafting adventure as I have to this one. Probably cause I"ve been wanting to do this for quite a few years.

Let me know about the venthood/bent metal barleybox Dale M. or anyone else in the KNOW

Thanks a million times
Michele
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Last edited by ShellyJo1969; 2009-08-05 at 2:58pm.
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  #15  
Old 2009-08-05, 4:25pm
ShellyJo1969 ShellyJo1969 is offline
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I found this really cook DIY tutorial on installing a vent hood.
http://www.easy2diy.com/cm/easy/diy_...ge_id=35743526

Here's the Vent Hood that Dale M. Suggested:
http://www.rangehoodsinc.com/product...-Hood-3p50.htm

And here is some vent hood ducting (and i don't know which kind or how much i need)
http://www.ducting.com/Short_Section_Hoses.html

So as far as I can tell it is simply mounting to a wall, cutting a hole, placing some ducting inside the wall to carry fumes to outside and connecting a outside wall cap.

What type and size of ducting do I need to purchase to go with this? the vent hood says it uses 6" round ducting. aluminum or steel? How long does it need to be? Looks like 1 ft. would be plenty for going straight out thorugh the wall.

Where do i buy the vent cover part for the outside and what size?

JoeDeM said:" I ran the numbers on that hood, and it's not possible to get 900 cfm with a 6" pipe as they claim the friction loss with 1 90deg elbow and say 6 foot run produces a friction loss of 1.07, and produces a 4586 fpm velocity, you would need a 10" pipe to achieve 900cfm"

Since it'll be going straight out through the wall, that shouldn't cause too much drag should it? Also isn't 600CFM the minimum needed?
michele
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Last edited by ShellyJo1969; 2009-08-05 at 6:34pm. Reason: added more info
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  #16  
Old 2009-08-05, 6:54pm
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Quote:
Originally Posted by JoeDeM View Post


EDIT: I ran the numbers on that hood, and it's not possible to get 900 cfm with a 6" pipe as they claim the friction loss with 1 90deg elbow and say 6 foot run produces a friction loss of 1.07, and produces a 4586 fpm velocity, you would need a 10" pipe to achieve 900cfm.
Where does it say you can not have a duct velocity of 4589 fpm?

Here is numbers with 10 ft of duct with 1 90 turn..



Here is numbers for 1 foot of duct and 1 90 turn... (assuming 90 degree turn directly on top of hood and going out through wall)



Dale
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  #17  
Old 2009-08-05, 10:11pm
NMLinda NMLinda is offline
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Quote:
Originally Posted by ShellyJo1969 View Post

Here's the Vent Hood that Dale M. Suggested:
http://www.rangehoodsinc.com/product...-Hood-3p50.htm

Since it'll be going straight out through the wall, that shouldn't cause too much drag should it? Also isn't 600CFM the minimum needed?
michele
Hi Shelly,

The amount of static pressure, or drag, isn't linear with pipe size, so you can pay a big penalty for small diameters like 6" when you need 90 degree bends, even though the rest of the length is very short, and you will need at least one bend to do what you want.

The cfm you need to net out after all of the static pressure is accounted for, ie the 'drag' produced by the size and length of the vent pipe to the outside as well as any bends you need depends on the width of the hood and how high you mount it above your work surface, as the links folks gave you in your other posts describe. The vent hood Dale offered for your consideration is 30", or 2.5' wide. If you mount it, say 27" above your work surface (or 2.25') with no back or sides (ie to turn it into a barley box), after all of your drag losses you would need to net out

703 cfm = 2.5 x 2.25 x 125

The drag losses, or static pressure, that Dale calculates for your plan to immediately vent out your wall with one bend and maybe one foot of pipe could easily cause you to lose 200 cfm or more with that much static pressure, or drag, depending on how the fan is made (a vent pipe from the fan itself that's bigger than 6" in diameter would have been better). Might be on the iffy side.

If you add three sides to this hood to make it a barley box, seal all the edges well, and seal the bottom edges to the workbench, the the cfm you would need to net out would be

563 cfm = 2.5 x 2.25 x 100

As you can see, either building a barley box or modifying something into one lets you get away with either a smaller fan, or a big fan with a fair amount of drag working against it. In the case of the vent hood Dale posted, you'd have

337cfm of margin = 900 cfm (what the fan does with no drag) - 563 cfm (what you need it to do after drag)

Although it's hard to say from the info provided, it's possible it might work.

Now, if you decide you want a wider hood, there is another model with the same fan that's 36" wide. Now you really have to be careful about the drag created by the 6" diameter pipe. The cfm you need to net out after static pressure, or drag losses is

938 cfm = 3 x 2.25 x 125 as is, no conversion into a barley box or
750 cfm = 3 x 2.25 x 100 sides added to turn into a barley box

For this width, you'd have to turn the hood into a barley box - the fan isn't big enough for this width even with no drag losses. Also, the 6" pipe drag loss is a bit of a problem, even though how you're thinking about installing it requires very little ducting.

If you click on the installation manual in the vent hood links Dale gave you, you will see a diagram that shows you what the hood looks like on the inside. Bet if you got one of these, the tall stack is just decorative to hide the vent pipes and very likely installs as a separate piece - which I wouldn't even bother attaching. Leaving that decorative piece off gives you easy access to the top of the hood where the vent pipe attaches. I would be tempted to get either a 6"-to-7" adapter ring or a 6"-to-8" adapter ring and use either 7" diameter ducting out the wall (with a 7" right angle bend) or use 8" diameter. Even a 1" diameter change in the vent pipe diameter significantly reduces the drag against the fan, particularly the drag caused by the 90 degree bend, and might let you use the next size up if you wanted.

Does this help you get a feel for how all this works?

Linda
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Old 2009-08-06, 12:29am
ShellyJo1969 ShellyJo1969 is offline
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Hi Linda, Yes, I don't know about the mathmatics involved, but you certianly sound like you know! Good thing somebody does.

I see what you're getting at though. So, I buy the hood, and don't use the top part if possible just attach a hose as close as possible to actual fan and straight out wall so it doesn't have to go very far and that increases fume drawing capabilities.

I have some corrugated sheet metal i found in the garage rafters that was leftover. Might i make a barley box from that to gather the fumes and using the fan as the top...that should work. It's long strips of metal about 3-4ft wide and 10-12 ft long. I should be able to bend that or even cut it if necessary (but bending would be better (less joints to join).

So If the hood calls for a 6" diameter hose to vent outside, how would i connect a larger one?

I need to buy:
1. Vent Hood
2. Hose (still dont know what type or diameter)
3. Hose clamps? to join hose to vent and run to outside
4. Outside vent cover

IS this it now? If someone knows about how to join the pieces together or what type of hose i need (metal, aluminum, etc) and clamps and vent covers, I'm so ready to get this stuff ordered!

thanks so much for your help
michele
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Old 2009-08-06, 12:34am
ShellyJo1969 ShellyJo1969 is offline
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The installation instructions do say you can vent right out side wall without going all the way up, at least that 's how it appears to me.

http://www.rangehoodsinc.com/product...-Hood-3p50.htm

if you go there it shows installation instrucions in tiny blue letters.
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Last edited by ShellyJo1969; 2009-08-06 at 12:50am.
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Old 2009-08-06, 11:56am
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Some thoughts here...

The DIY Network tutorial is pretty good, it covers basics, though some of the the steps will be a bit different, its basically what the process is.

When coming off vent hood with your ducting it may be better to upgrade from 6 inch duct at hood flange (using adapter) and go to at least 8 inch duct and bends to complete duct path to outside...

For actual duct materials, use either steel or aluminum rigid duct, do not try to use bendable or flex ducting as it increases resistance to air flow and makes your vent system less efficient.

Stay away for any form of plastic ducting is is not rigid enough to maintain shape under high heat and is also not conducive to air flow...

I know comments sound strange because most home heating and AC system use plastic or metal flex ducting but they are working with cooler temperatures and a lot less volume ... For instance my home which has 2100 square feet only has a 1750 CFM blower on HVAC system and yet it can maintain ac level of about 80 degrees inside when temps outside are around 102 degrees and in winter a comfortable 68-70 degrees when temps outside are down in 30's... But the volume of air being moves is pretty much a constant in a closed loop system...

Dale
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Last edited by Dale M.; 2009-08-06 at 12:03pm.
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  #21  
Old 2009-08-06, 12:29pm
ShellyJo1969 ShellyJo1969 is offline
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Ok so where do I get the Adaptor to go fro ma 6 inch duct to a 8 inch?

Will these rigid vent duct's be what I'm needing to buy?
http://www.theductshop.com/shop/cata...ows-c-1_4.html

Also this is a striaight piece of it
http://www.theductshop.com/shop/cata...uct-c-1_3.html

I don't know how much to buy of each?
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Last edited by ShellyJo1969; 2009-08-06 at 12:43pm.
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Old 2009-08-06, 12:44pm
NMLinda NMLinda is offline
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Quote:
Originally Posted by ShellyJo1969 View Post
I have some corrugated sheet metal i found in the garage rafters that was leftover. Might i make a barley box from that to gather the fumes and using the fan as the top...that should work. It's long strips of metal about 3-4ft wide and 10-12 ft long. I should be able to bend that or even cut it if necessary (but bending would be better (less joints to join).
Sure, you can probably make it work. The corrugations may be a bit inconvenient when trying to seal it against a range hood like the one Dale posted, if that's what you decide to get. If you plan carefully how and where you cut the corrugated metal before you bend it to shape, though, it might not be too bad.

Quote:
Originally Posted by ShellyJo1969 View Post

So If the hood calls for a 6" diameter hose to vent outside, how would i connect a larger one?
Please see my comment about the adapter ring. Once you go someplace like Home Depot or Lowes and look at one, I'm sure it will make sense to you. It will be a relatively short piece of round metal duct that's 6" diameter on one side and a larger diameter on the other (ie 7" or 8" - they come in different combinations of sizes)

Quote:
Originally Posted by ShellyJo1969 View Post
I need to buy:
1. Vent Hood
2. Hose (still dont know what type or diameter)
3. Hose clamps? to join hose to vent and run to outside
4. Outside vent cover
I don't recommend hose of any kind. I recommend you use round smooth-walled sheet metal ventilation ducting. This generally come in 3' or 5' lengths, and can be found in the same aisle in places like Home Depot as the adapter rings. The 3' length might be enough, and can easily be cut down with a tin snips if it's too long. To be able to go out the wall behind your hood, you'll need a 90 degree bend that's the same diameter as the vent ducting you pick. You don't really need hose clamps in your case - duct tape should work fine to hold eveything together.

To keep out flying things, consider geting metal screen, like that used for venting eaves, to cover the end of the duct before you attach any kind of vent cover (be careful what you choose, here, these add to the static pressure drag on your fan in a similar way as a bend).

As exciting as it is to get going, I urge you to pause a bit - you have some important decisions you'll want to make before you spend your hard-earned money. You first need to decide how wide a vent hood you want, especially if you add sides to make it a barley box. You might want to sit down at an imaginary workbench and try to visualize what seems comfortable. The amount of working room, ie width, is a personal taste thing - all we can do is just offer some ideas and the important fan considerations that go along with those ideas.

The other thing you need to decide for yourself is how much you want to increase the diameter of the 6" output of the hood Dale recommended, if that's what you choose to buy and if that's what you choose to do. If you look at the number Dale highlighted in purple on the spreadsheet he posted, the smaller that number, the better, and the less your fan's starting, or 'free air' cfm will be reduced. You can make this number smaller by going with bigger diameter vent ducting/90 degree bends. The smaller that number, the less risk that the cfm you get at the end of all this will be less than what you need for the hood size you pick.

I strongly recommend you use Dale's spreadsheet as a guide and go to the ventilation primer link folks posted for you in your other threads. Calculate the static pressure first for 7" and then for 8" (short section of duct and one 90 degree bend, as Dale did). I recommend comparing 7" and 8" because the static pressures drop a fair amount compared to 6" and it's not too hard to find the vent duct parts in those sizes. If you think you want to buy the range hood Dale posted, try calling to see if you can find out what the fan's cfm drops down to when looking into the static pressure Dale calculated for 6" and what you calculate for 7" and 8". That will further help you decide what diameter pipe to select.

In recommending this process, I'm coming from the philosphy of measure twice - or three or four times - and cut once. Mistakes are cheaper on paper.....

Linda
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  #23  
Old 2009-08-06, 12:49pm
NMLinda NMLinda is offline
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Ok so where do I get the Adaptor to go fro ma 6 inch duct to a 8 inch?

Will these rigid vent duct's be what I'm needing to buy?
http://www.theductshop.com/shop/cata...ows-c-1_4.html

Also this is a striaight piece of it
http://www.theductshop.com/shop/cata...uct-c-1_3.html

I don't know how much to buy of each?
That's the right kind of bend and straight sections to use in my opinion - smooth walled metal ducting. Lowest loss, and I find it easy to use. You can find the same things at Lowes and Home Depot, too.
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Old 2009-08-06, 5:53pm
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Where does it say you can not have a duct velocity of 4589 fpm?

Dale
Nowhere, but I prefer to use a larger duct to reduce the friction loss, at 1.07 you lose as much as 20 to 30%, granted at 900cfm even with the loss it would be acceptable, besides you yourself always recommend at least an 8" duct anyway. Also running at a lower fpm reduces the noise level as well.
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Old 2009-08-06, 6:36pm
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Nowhere, but I prefer to use a larger duct to reduce the friction loss, at 1.07 you lose as much as 20 to 30%, granted at 900cfm even with the loss it would be acceptable, besides you yourself always recommend at least an 8" duct anyway. Also running at a lower fpm reduces the noise level as well.
Yes I always recommend larger duct, but in this case hood only has 6 inch opening, and if one is going directly into a 90 degree turn and out through a wall... With less than a total of approximately two-three feet of duct, it really is not going to make much difference.... If it was 20 feet I would yes go to larger duct, but with such a short run I see no advantage ...

Dale
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Old 2009-08-06, 7:14pm
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Originally Posted by ShellyJo1969 View Post
Ok so where do I get the Adaptor to go fro ma 6 inch duct to a 8 inch?

Will these rigid vent duct's be what I'm needing to buy?
http://www.theductshop.com/shop/cata...ows-c-1_4.html

Also this is a striaight piece of it
http://www.theductshop.com/shop/cata...uct-c-1_3.html

I don't know how much to buy of each?
Reducers also work the opposite way as expander (small to large)...

http://www.theductshop.com/shop/cata...rs-c-1_12.html

Dale
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Old 2009-08-06, 8:18pm
ShellyJo1969 ShellyJo1969 is offline
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Great Dale, so should i get a size 6to8 reducer and just turn it around backwards so that it increases the size of duct i can use?
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Old 2009-08-06, 10:44pm
ShellyJo1969 ShellyJo1969 is offline
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OK, I ordered the vent hood. Now I went to the page dale found for the ducting and this is what i came up with

*Two 8x6 reducers
*One 8" 90degree adjustable elbow
*Three Eyebrow vent covers one for outside of ventilation system and two for fresh air vents inside and out.

Here's what I'm thinking:

Need Two 8x6 reducers (One attaches to the 6" vent hood pipe and converts it to 8" size on other side then I connect the 8" 90degree adjustable elbow and go out the wall hole with it then attach the other 8x6 reducer where it comes out the wall on outside of building so I can put on this 6x6 eyebrow as the finishing touch on the outlet side (outside) of building to keep bugs/birds/weather out and let the bad fumes escape.

Plus if I buy two more eyebrow vents and remove baffle just leaving the screen part, i could use those as my fresh air intakes under my bench. Cut hole in wall put one on outside facing down to keep out weather and one on inside facing upward to bring me fresh air.

THAT WILL WORK WON'T IT DALE??? PLEASE SAY YES!

Other than constructing some type of barley box to go with this ventilation system, does this look like all i'm needing. I"ll be sOOO glad to have this part finished!

http://www.theductshop.com/shop/shopping_cart.php

how does that look Dale?
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Last edited by ShellyJo1969; 2009-08-06 at 11:00pm.
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  #29  
Old 2009-08-07, 5:26am
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Originally Posted by ShellyJo1969 View Post
OK, I ordered the vent hood. Now I went to the page dale found for the ducting and this is what i came up with

*Two 8x6 reducers
*One 8" 90degree adjustable elbow
*Three Eyebrow vent covers one for outside of ventilation system and two for fresh air vents inside and out.

Here's what I'm thinking:

Need Two 8x6 reducers (One attaches to the 6" vent hood pipe and converts it to 8" size on other side then I connect the 8" 90degree adjustable elbow and go out the wall hole with it then attach the other 8x6 reducer where it comes out the wall on outside of building so I can put on this 6x6 eyebrow as the finishing touch on the outlet side (outside) of building to keep bugs/birds/weather out and let the bad fumes escape.
You don't want to reduce it back down to 6", it defeats the purposes of going to 8" in the first place.
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  #30  
Old 2009-08-07, 6:19am
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Paul Ewing Paul Ewing is offline
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Ok, I don't think you need an eyebrow on the inside of your fresh air duct.

since the place you are looking only carries 6-inch eyebrows, I wouldn't bother upsizing to 8-inch if you are just going back down to 6-inch. You will have more problem from the turbulence o reducing the size than you would gain from using an 8-inch turn. My recommendation would be to use an 8-inch eyebrow fitting if you can find one. Anyway, it is generally accepted that you will want your fresh air to be a size bigger than your exhaust since it is free air entry instead of fan assisted. Do a search for exhaust vent dampers and see if you can find larger ones.
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