# 6' Fume Hood



## Noxx

This is my design of my temporary fume hood that I'll use for Au & PGM refining. 

A good project starts with good planning.







Tools/Material needed for this are:

-4' x 8' Melamine boards (5/8'' for me)
-2'' x 4'' Wood
-Wood/Drywall Paint
-Various Screws
-Drill
-Pick-up truck (Bought a B4000 '98)
-Benjamin Moore Polyamide Epoxy Paint (P36)

Work surface is around 6' x 27'' and all the inside surfaces will be coated with industrial grade epoxy. 

I did my CAD drawing based on the base that I already made.

Base:






**UNDER CONSTRUCTION**


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## jimdoc

What is the pickup truck for? Is it going to be a mobile fume hood?

Jim


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## Noxx

No haha, it is for transporting everything needed for my business... 4x8 boards, wood, metal, chemicals, equipment, etc...


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## philddreamer

"The difference between a dream & reality is, a good plan!" 8)


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## glondor

Good Job Noxx! Epoxy paint is a very good idea. 27 is a good depth as well. Mark a line 6 inches inside the doors and work on the far side of it. (keeps you safe) What kind of door system are you going to use? Mine is a slider that I can pin at various heights depending on what process I am doing. I like it.


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## samuel-a

Noxx said:


> A good project starts with good planning.



That's a healty thinking Noxx.

Iv'e been toying around with this design idea, i gathered it from different desigens seen on the net.
With basic assumption that the suction should not be ditected only upward, but also away from the operator.

i implemented it in your design, sorry for the way it looks btw:




This seems easy enough to build, the only question, will it work?
Any thoughts?


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## glondor

Here is the door system on mine.








early stages of construction





Hard at work


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## Noxx

Painting the pannels:


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## Noxx

I worked more on this in the last two days and managed finish the frame...


























The door will be custom made tempered glass.

This hood needs about 1800 CFM, so I'll use a 10'' PVC pipe for exhaust.


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## philddreamer

Looking goooood!! 8) 

Phil


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## Harold_V

That looks *very *nice, Jean!
My light was similar to yours. Great way to light the interior. 

Harold


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## Geo

that does appear to be good handy work.you may make a good handy man. :lol: will the opening in front be closed up any or will the door be as big as the opening is now?


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## Noxx

Thanks  

The door will be 6' long too (1/4'' thick tempered glass).


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## Noxx

First CAD dwg of the door.

Also, I decided to make a chemicals cabinet under the hood with wood scraps I had.

CAD dwg here too.


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## Oz

That is looking good Noxx!

I will be nice to hear how your epoxy paint holds up over time. Keep us posted.


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## goldsilverpro

Instead of one big sheet of glass, have you thought of about 4-6 narrow sliding panels of glass riding in 2-3 routered grooves at the bottom and top? You could glue small rectangular pieces of plexiglass on the glass as handles. Sounds safer and you'd have a variable opening. You wouldn't need a total seal between the panels.


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## glondor

I really like the slidey uppy door. I have stops at 4, 8, 16 and 30 inches. For a full on dissolution I keep it at 4 or 8 inches open. For milder reactions I can have it open to 16 inches and still work filtering and such with no fumes. When doing a set up or decanting I can open the full 30 inches and work away. 

At full open it works well for melting. Lots of room and no metal fumes. Easy to move buckets in and out. Sliding up gives very good CONTROLLED access to the material in the hood.


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## Noxx

goldsilverpro said:


> Instead of one big sheet of glass, have you thought of about 4-6 narrow sliding panels of glass riding in 2-3 routered grooves at the bottom and top? You could glue small rectangular pieces of plexiglass on the glass as handles. Sounds safer and you'd have a variable opening. You wouldn't need a total seal between the panels.



No, I did not think of this... I don't see how it would be safer ?



glondor said:


> I really like the slidey uppy door. I have stops at 4, 8, 16 and 30 inches. For a full on dissolution I keep it at 4 or 8 inches open. For milder reactions I can have it open to 16 inches and still work filtering and such with no fumes. When doing a set up or decanting I can open the full 30 inches and work away.
> 
> At full open it works well for melting. Lots of room and no metal fumes. Easy to move buckets in and out. Sliding up gives very good CONTROLLED access to the material in the hood.



My door, in opposition to your design, won't use pins. It'd be risky to hold 60-70 lbs of glass with two pins. For this reason, the door will have counterweights like a real fume hood.

What's the rating of your blower ?


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## glondor

Hey Noxx. I do not really know the rated cfm of my blower. It is a furnace blower for a house so it does move a large quantity of air. My main restriction is the out flow pipe as the building owner where my shop is would only allow me to use an existing roof thru point and it is too small and too far away. Thankfully he has agreed to allow me to install a 12 inch cone directly above my hood. This will improve my air flow greatly. I am going to try to get some 10 inch plastic water main from a local construction project and use that as the outflow. The furnace blower has held up well to this point but does require twice daily inspection. I have laid a little beach of baking soda around it on the top of my hood and check regularly for little drips on the bicarb. The weakness is oem holes in the blower case that I initially plugged with caulk. I patch with construction adhesive applied to a 6 mil poly sheet. When this one gives up I will try the same model treated with epoxy paint and see how it does. 

I would like a proper unit but it is out of the budget at this time. They are very expensive.


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## qst42know

I don't recall any discussion of how a blower of any type draws anything
with the door fully closed?

Where is the inlet when the door is shut?

But still it might be beneficial to be able to close it completely in the event of a power outage.


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## glondor

The door should never be shut while working. You need an opening to draft thru. Closing at the end of the day is good when blower is off.


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## qst42know

How are commercial fume hoods constructed for incoming air?

Does the blower switch off if the door is shut?


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## Noxx

I strongly recommend anyone who wishes to build a fume hood to read this.

UCBS Chemical Fume Hood Guide


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## qst42know

So you do need a horizontal opening along the bottom of the door. Essentially the door never does shut completely. And a glass door is the proper choice.

An interesting document Noxx, Thanks.


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## Noxx

A few more pics:







Notice that this frame is not touching to the ground. There is 0.5'' of clearance.

















The blower is ordered (Plastec30, 2HP - 2500CFM) and I ordered an AC drive to control the power.


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## Noxx

For those who don't know, an AC drive (Variable-frequency drive) is a system for controlling the rotational speed of an alternating current (AC) electric motor by controlling the frequency of the electrical power supplied to the motor.

I bought this one:

http://www.factorymation.com/s.nl/it.A/id.196/.f?sc=2&category=32






My blower works on 230V three phases but I only have one. Fortunately, this little device can operate on 1 phase and output 3 phases!


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## glondor

Very nice Noxx. The hood looks good. Where did you end up getting your blower? Do you have a link?


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## Noxx

jimdoc said:


> What is the pickup truck for? Is it going to be a mobile fume hood?








Installed the butterfly damper on top of the hood.


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## 4metals

Nice job Noxx.

Looks like you majored in chemistry and minored in carpentry!


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## Noxx

A nice package was waiting for me to pick up today.

It's the Plastec blower!






Installation will begin tonight.


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## 4metals

> It's the Plastec blower!



That really sucks!

(Sorry I couldn't resist) :lol:


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## HAuCl4

This "fume processor" works for 99.999% of refiners (400 oz a day or less):
http://www.ridgid.com/Tools/12-Gallon-Vac/index.htm

Two plastic drums full of plastic balls and soda ash are not included in the $70 price tag. :shock: 

Noxx likes to hunt flies with elephant guns. :lol:


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## Noxx

First power up of the blower (no air ducts):

[youtube]http://www.youtube.com/watch?v=gekDrmdLtL8[/youtube]


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## Harold_V

Very nice, Noxx. Variable speed? I could have used that feature to great advantage during the winter months, when evaporating. I think you're going to enjoy the setup. 

Harold


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## 4metals

What is the maximum CFM of the blower? How expensive is the Plastec blower? I'm sure you will enjoy a long life with minimal maintenance from the blower. And once the ducting is complete, it will quiet down considerably.


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## TXWolfie

Hey Noxx I wonder if that budlight can in the last cabinet pic adds to on the spot creativity :lol: :lol: :lol: :lol:


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## Noxx

TXWolfie said:


> Hey Noxx I wonder if that budlight can in the last cabinet pic adds to on the spot creativity :lol: :lol: :lol: :lol:



No Budlight for me friend, I don't like light beer. It's a Bavaria, straight from Hungary.



4metals said:


> What is the maximum CFM of the blower? How expensive is the Plastec blower? I'm sure you will enjoy a long life with minimal maintenance from the blower. And once the ducting is complete, it will quiet down considerably.



The Plastec30 blower is rated at 3500CFM @ 2HP (0'' H2O) or 2500CFM @ 2'' H2O. It is considerably more than what I need but it will also operate another hood for my propane furnace. Both need to run simultaneously.

The blower is around $1500 CAD here, maybe slightly cheaper in the US.


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## glondor

Where did you source the blower Noxx. If it is $1500 it is a good find for sure. NIce cfm rating as well.


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## Noxx

I contacted Plastec and they referred me to Master. They have offices near Montréal. It was a special order and there's a two weeks delivery time.


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## Geo

that really is a quiet running blower, not at all what i was expecting to hear. and with the duct work hooked up i doubt you will hear that much noise.


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## TXWolfie

Noxx said:


> TXWolfie said:
> 
> 
> 
> Hey Noxx I wonder if that budlight can in the last cabinet pic adds to on the spot creativity :lol: :lol: :lol: :lol:
> 
> 
> 
> 
> No Budlight for me friend, I don't like light beer. It's a Bavaria, straight from Germany.
Click to expand...


I dont like light beers either they have to have a good taste to them and I will take that as a yes to the on the spot creativity ..... :lol:


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## Noxx

Sorry for the pic quality, but here's how it looks like when I test fitted the ducting:


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## qst42know

Looking great Noxx. 8)


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## glondor

Hey Noxx. Looking good. Is that 10'' HDPE pipe?


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## Westerngs

Words of advice for future fume hood builders:

Try to stick to all plastic construction materials and especially avoid wood.

Reason: Wood absorbs acids, nitric or hydrochloric, and eventually becomes extremely flammable. We had a very large fire because the wood base on 2 fume hoods caught fire just from a hot plate being close. Just the heat from the hot plates caused the wood to catch fire.

Further, a fire extinguisher was used to suppress the fire, and the user thought he had completely extinguished it so he called the fire department to cancel the fire alarm. In the few minutes it took him to do that, the wood had re-ignited and most everything in the room was fully engulfed in flames. Well over 100K in damage and we had a 10K deductible on our insurance coverage. It was an expensive way to find out.

Ever since, we have made everything out of plastic and 15 years later it is still intact. PVC, Polypropylene, FRP, all plastics work well.


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## slickdogg

Westerngs

what if the wood was sprayed with a urethane sealer
and finished with a high mil (18 - 22 mils) rubberized under coating?


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## Photobacterium

Westerngs said:


> Reason: Wood absorbs acids, nitric or hydrochloric, and eventually becomes extremely flammable.



THANKS for that reminder !

i'm building a fume hood workbench right now. the bottom is a heavy butcher block door, so that determined the size - 31.5" x 79" (big). i wanted something heavy at the bottom.

the fan arrangement is -
3 box fans
3 high speed vaneaxial 80 mm
1 high speed vaneaxial 120 mm

now i'm realizing the fans need to be considered relative to the fumes ... obvious to some. for the fan plenum i was going to use wood ... now it will be wood lined with plastic film. they are DC fans with a fused power supply plugged into a circuit breakered powerstrip.

the chimney is already in place - galvanized 6 inch pipe. i'm wondering about that part after reading this thread. the objective being to outwit Mr. Murphy.


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## Noxx

I understand that wood is not the perfect material for a fume hood. However, since I do not use organic solvents, the risk of a flammable spill is non-existent. Also, all the wood is epoxy coated which means that it does not absorb chemicals.

I think your worst enemy would be HNO3 since it provides oxygen when burning. I don't see how HCl would help combustion...


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## Anonymous

I have a very important question................where the heck is your car Nic?If you sold it and bought that truck instead,I am leaving the forum for good! 
I am surprised you don't own a beamer truck also?With gold plated 24" rims......just kidding you bid.Everything looks great.And I especially agree with the light comment from Harold,that is a great idea.


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## Noxx

I did not sell any of my cars, I have 4 now...

Please stay on the forum


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## Anonymous

Don't worry Nic,I'm not going anywhere.Not unless you,or one of the mods tell me to......and even then I am putting up a fight.I have been here too many years to leave now.


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## Westerngs

slickdogg, With all that coating I would say you're ok. It will eventually wear out, so recoat every so often.

Noxx, the acids make the wood decay, making it more flammable. Both nitric and hydrochloric do this as they are both oxidizers. As with slickdogg, the coating will slowly wear away, even more so with acid spills, so recoating once in a while would be a good investment.


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## slickdogg

Westerngs,

Thanks for the information 8)


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## watcher6880

Just wondering if a kitchen range style hood can be used in this type of setup?? Or does it not have the right exhaust pressure? Just an idea but if I am wrong I would gladly take the criticism as constructive


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## Smack

Nope, not a good idea. Won't hold up to the chemicals and will not move enough air.


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## watcher6880

Just what I thought. Now why is it I have heard that box fans are more effective? Is it because of the fact that box fans are made of mostly of plastics or are these just isolated to halfa**ing jimmy riggers? I mean no insult by that last line.


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## Geo

a 20 inch box fan is in my rigged up fume hood. been 6 months and still working.it does pull alot of air but when i can, i will do a better job on it.


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## Noxx

I had some time this week-end to finish the installation (it wasn't too cold outside but snow made the roof slippery).

Modified 10'' dia duct with spacers ready to accept the 12'' dia. rain cap.





Fitment is perfect.





1/32'' Galvanized steel wire is used for support





Finished rain cap.


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## Smack

How does a tube over another tube keep the rain out Noxx? Can't tell if there is something else in the bigger tube to deflect the rain.


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## jack_burton

Smack: He says in his last post up there, he's going to put a 12" dia. rain cap over top.


Noxx: Very cool set up, and I thought I was kicking ass hand building my work bench. Hopefully someday I will have a need for such a professional hood! :mrgreen:


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## watcher6880

Another thing I am wondering.... I see all of the controversy surrounding the issue of using wood for framing... being that acids can be absorbed into the wood. Making it much more flammable. What if adding porcelain or ceramic tiliing to top on the hood/ workbench over the plywood would make it any safer?


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## glondor

I think chopping on some fiberglass may be better, but it might not be cheaper. When mine gets a rebuild I think this is what I will do. I have put a epoxy coated steel pan in the bottom of mine for now as the fire danger is very real. I would love to get a hold of a nice 1000 gal fiberglass tank and mod it to suite. I used to get dozens a year when i did demolition, crushed them and sent to land fill...If I only knew then what I know now.....


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## watcher6880

Thanks, I have the fiberglass fabricating and reworking experience to build my own so that is definately a route to go about... At Lowes they sell bathboard but it's not thick enough to hold as a wall...so taking the fiberglass bathboard and adding more layers of chop and matte to make it thicker might work as well. Make a few sheets to do the entire project and then saw what you need. They come in 4x8 sheets.. Also if someone doesn't want to waste all that time, they do have fiberglass shower stalls with drains (this could be modified and the tub part of the stall would be perfect). Just 'glass off the drain (flat) and then add plexiglass to the front of the hood. Just an idea. Any other ideas added to this are welcome.


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## Noxx

According to the document I provided, fiberglass should not be used.

They say that when it burns, it releases huge amount of noxious smoke...


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## qst42know

The right epoxy might be worth looking into.

http://www.epoxysystems.com/640.htm


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## eeTHr

Noxx---



Noxx said:


> Modified 10'' dia duct with spacers ready to accept the 12'' dia. rain cap.





From Re: Lab Hood, Ventilation & Scrubber System Design---



Noxx said:


> No airflow restricting rain caps allowed.






Smack said:


> How does a tube over another tube keep the rain out Noxx? Can't tell if there is something else in the bigger tube to deflect the rain.





So, what _*is*_ inside your 12" diameter "rain cap"?


:?:


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## Noxx

It's not a ''proper'' rain cap. In fact, it's just two concentric tubes. 

Since rain rarely does fall straight down, the outer tube acts as a guide to drain the water outside of the air duct.

It's a bit hard for me to describe so here's a schematic:


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## Smack

I understand what you did. Mine exits out the roof vertically also, but I just put 3 45's on it.


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## Barren Realms 007

Noxx said:


> It's not a ''proper'' rain cap. In fact, it's just two concentric tubes.
> 
> Since rain rarely does fall straight down, the outer tube acts as a guide to drain the water outside of the air duct.
> 
> It's a bit hard for me to describe so here's a schematic:



Noxx, I feel you are setting yourself up for a problem. If I am looking at this correctly your 12" pipe is sealed on the top, your air circulates up to the top and then back down and out between the 10" and 12" pipe. Calculate the area of the 10" pipe and then calculate the area of the 12" pipe. Subtract the figures and see if they equal less than the area of the 10" pipe. It will not actually be a 2" space between the pipes it will be less by the thickness of the wall of your 10" pipe so your calculation will be off just a little bit.


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## qst42know

No you don't close the top. It's a stack within a stack type. Bad diagram you can't read the dimensions.

http://www.swcleanair.org/Forms/78-RainCapsExhaustStacks.pdf



Though I think I see a small problem with the installation. When you do get more snow on the roof ice may build up between the two pipes and break one of them.


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## eeTHr

Noxx said:


> ...it's just two concentric tubes.
> 
> Since rain rarely does fall straight down, the outer tube acts as a guide to drain the water outside of the air duct.





Ahhhhh! Now it all makes sense! 8)


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## eeTHr

qst42know said:


> diagram....
> 
> http://www.swcleanair.org/Forms/78-RainCapsExhaustStacks.pdf




It would be cool to put a hex type on bottom to catch the straight down rain, and a stack in a stack type on top of it, to divert the angled rain.


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## 4metals

In my opinion the tube within a tube type of raincaps are the best for refining. They have been around for years and I have used them often. One big plus is that the exit velocity of the fume is not inhibited by any obstructions and the exhaust blows straight up (not diverted to the side as with a typical "witches hat" raincap. 

As Noxx said the amount of rainfall falling straight down is suprisingly little and the difference in length between the shorter inside pipe and the longer outside pipe can be extended to trap any rain falling at any angle greater than about 5 degrees from straight down and divert it off to the side of the main (center) pipe.

Good choice Noxx!


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## HAuCl4

I'm sorry to be the party-pooper, but all of this setup looks to me as extreme overkill.


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## glondor

RE extreme over kill..........................could you please explain a bit what you mean. I Think over all it is a great system Noxx has put together. There are a few things I would have done a bit different, but that's just my preference. So Haucl4...please tell what is over kill.


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## HAuCl4

glondor said:


> So Haucl4...please tell what is over kill.


Overkill: Hunting rabbits with a nuclear weapon. Killing flies with a shotgun. Metaphor for "expensive and ineffective" at the same time.

This setup is expensive, ellaborate, complicated, and I don't believe it even scrubs the fumes before releasing into the atmosphere. All in all a very poor deployment of capital and effort. Just my opinion, of course. 

When I saw the photo of the "chimney" in the roof with the snow and the cables, it became over the top for me. I just had to say something. Sorry.

Nothing personal Noxx.


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## goldsilverpro

HAuCl4 said:


> glondor said:
> 
> 
> 
> So Haucl4...please tell what is over kill.
> 
> 
> 
> Overkill: Hunting rabbits with a nuclear weapon. Killing flies with a shotgun. Metaphor for "expensive and ineffective" at the same time.
> 
> This setup is expensive, ellaborate, complicated, and I don't believe it even scrubs the fumes before releasing into the atmosphere. All in all a very poor deployment of capital and effort. Just my opinion, of course.
> 
> When I saw the photo of the "chimney" in the roof with the snow and the cables, it became over the top for me. I just had to say something. Sorry.
> 
> Nothing personal Noxx.
Click to expand...


HAuCl4.

Were you someone that people listened to, that would have been a cruel thing you said. Noxx built this beautiful fume hood and you knock it. Do you have any friends?


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## HAuCl4

Well. I consider both you and Noxx as friends as far as "online friendship" goes. I certainly do not have "enemies" in this forum or online. I just spoke my heart, and what I believe it's the truth. It's a contraption that blows fumes into the atmosphere. Maybe it's "beautiful" as fume hoods go...Not for me. I don't take back any word I wrote. Cheers.


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## glondor

Sooooo, What you really meant to say is in your opinion it is not complete yet with out a scrubber. In essence "underkill" for its intended use? Not trying to put words in your mouth, just trying to clarify your issue with the system.


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## HAuCl4

glondor said:


> Sooooo, What you really meant to say is in your opinion it is not complete yet with out a scrubber. In essence "underkill" for its intended use? Not trying to put words in your mouth, just trying to clarify your issue with the system.


No. What I meant is what I wrote. And I do not intend to defend or explain it any further after this post. You can search for yourself in this same forum better and cheaper systems and methods for dealing with fumes. In all honesty the carpentry work looks great. It's just the cost of the blower and the deployment of the pipes, without scrubber, the main objections that I have. Cheers.


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## goldsilverpro

It's a fume hood. A scrubber is another thing all together.


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## kuma

Evening all!
I hope all is well!



HAuCl4 said:


> glondor said:
> 
> 
> 
> So Haucl4...please tell what is over kill.
> 
> 
> 
> Overkill: Hunting rabbits with a nuclear weapon. Killing flies with a shotgun. Metaphor for "expensive and ineffective" at the same time.
Click to expand...





I have no educated take on this , as you all know I am a noob and know not a lot , but my personal opinion is Noxx' fumehood and extraction system is awsome , someone had to do it , and I for one am envious , nice work there chief , 8) 
With the kindest regards and upmost respect for all , 
Chris :mrgreen: 

( P.S. , people should smile more , ... http://tinyurl.com/6rpoom4 8) )

(fixed link :mrgreen: )


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## Geo

for an amateur that only processes a small amount at a time i would have to agree, but neither you nor i know what amounts he may be dealing with, and if your speaking about chemical pollutants in the atmosphere, it looks to me like Noxx has followed the guidelines very well.as a challenge to Haucl4, please post some pictures of your fume hood so that we may compare the design and functionality of the two so the members can make a better assumption as to whether or not you have a valid argument.


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## glondor

That is a very good idea Geo. I will post pics of a few changes to mine as well. For that matter let's see everyones and we can compare notes!


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## HAuCl4

Geo said:


> .as a challenge to Haucl4...


 Challenge declined. You win. Go and collect your prize.


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## Smack

Well then, I'll not post a pic of my 6' BMC fume hood, don't want to ruffle haha. I think you all lit into HAuCl4 a bit too much. He only made an observation and gave his opinion, he initiated no argument, other people did. I understand why you all are so quick to defend Noxx but that's just politicking, besides Noxx is a big boy, if it bothers him, let him speak for himself. Free will still rules, so spent as much or as little as you want on whatever. One of my sayings "If it's worth doing, it's worth doing right" but I don't think I would have spent that much on the blower either, but that's just me. I would still like to have one though.


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## Noxx

HAuCl4,

I understand that it might be overkill for backyard PM refiners however, I have an Inc. company and I need to follow environmental laws if I don't want to have fines.

I plan to add a scrubber to the system, however it is still on the drawing board.

There will also be a second hood attached to the blower, and both need to be able to run simultaneously.

Finally, I plan to hire someone this summer or autumn so Personal Safety is a must here.

P.S. No offense taken 8)


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## goldsilverpro

You done good, Noxx.


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## HAuCl4

Sounds good Noxx. Best of luck with the business and environmental agencies. I suspected you couldn't be running that setup and process big enough quantities without a scrubber...

Cheers.


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## HAuCl4

If you keep that fume hood to make pancakes and boil coffee, and your refining acid fumes in the scrubber system, you have a good chance of passing the environmental inspection. (joke).

Now all others can proceed to attack me again... :lol: 

Have a nice Sunday. 8)


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## Noxx

Today I start building the furnace fume hood (made of Stainless Steel).


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## 4metals

Noxx,

Have you ever totaled your supplies, (glass, epoxy, lumber, lighting etc.) for this hood and your time to build it? I'm trying to get a comparison between having one made by a fabricator and a DIY hood.


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## Noxx

Yes, here's a rough estimate:

-Wood: $200
-Misc parts: $100 (acrylic, screws, pulleys, steel, etc)
-Epoxy paint: $100 (still a lot left)
-Tempered glass: $200

Total: $600

That's for the hood only.

I'm not sure about the time though since it's still unfinished. If I had to build a second one, it'd go much faster.

Next time I might try to build one in steel instead...


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## butcher

Noxx, check around, I got a nice chemical fume hood asbestos’s lined for free, the hospital just wanted rid of it, complete with some stainless ductwork and chemical resistant base (Bakelite ?), who knows you may find a school remodeling.

Another option is look for old flammable liquid storage cabinets, the old ones were lined with asbestos’s sheets, and you could make a fume hood from it with some modifications.

Maybe also check for salvage company’s who resale industrial supply’s.

https://www.google.com/#hl=en&q=used+chemical+fume+hood+for+sale&oq=used+chemical+fume+hood+for+sale&aq=f&aqi=&aql=&gs_sm=s&gs_upl=9247l15011l0l16932l14l14l0l0l0l0l203l2046l1.12.1l14l0&bav=on.2,or.r_gc.r_pw.,cf.osb&fp=56e9d7616fefd86b&biw=1152&bih=660

When it comes to running a bussiness and following the clean air acts or other regulations there is no such thing as overkill.


http://www.ebay.com/itm/Nuaire-NU-435-600-Class-II-Biological-Safety-Cabinet-/310372025142?pt=LH_DefaultDomain_0&hash=item48439d4336

http://www.ebay.com/itm/Wet-Chemical-Fume-Air-Scrubber-Harrington-5-10K-CFM-/280366906782?pt=LH_DefaultDomain_0&hash=item41472b7d9e

Maybe find one of these for free.

http://www.ebay.com/itm/30-Gallon-Metal-Flammable-Storage-Cabinet-/230380148246?pt=LH_DefaultDomain_0&hash=item35a3ba1616


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## Noxx

Thanks for the links Butcher 8) 

One a side note, I decided to add an heat shield to this dry wall since the propane furnace is gonna be close to it. This Al sheet costs only $60 I think.







I also bought a CO/Propane gas detector that you can barely see on the bottom right. It displays the PPM concentration and works well so far.


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## butcher

I am not sure what type of heat shield your adding to your wall, but spacing it off away from the wall, (air space between heat shield and the wall), will help keep wall cooler, few inches (air gap),is all needed.


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## HigginsMechanical

Noxx said:


> Thanks for the links Butcher 8)
> 
> One a side note, I decided to add an heat shield to this dry wall since the propane furnace is gonna be close to it. This Al sheet costs only $60 I think.
> 
> 
> 
> 
> 
> 
> I also bought a CO/Propane gas detector that you can barely see on the bottom right. It displays the PPM concentration and works well so far.




Looking good, Noxx....


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## HAuCl4

Hi again Noxx. Another stupid idea of mine is to always have the furnace in the center of the shop, away from all walls and with plenty of room all around it. 8)


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## watcher6880

Looks great Noxx... I think that if any one is running a legitimate incorporated refining business they should take your design into consideration as a model design. It may be "Expensive overkill" but it sure beats the hell out of spending thousands on a state of the art commercially produced fume hude.


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## chemist_12

Hi Noxx,

Some thoughts on your fume hood:

I don't like that it opens from the side, rather than from the top. I would recommend checking the airflow with some type of smoke, to see how far you can afford to have it open when it is in operation. I can tell you from considerable experience working in a fume hood that it is going to be a lot quicker to do things in it if you can just lift the entire hood sash a bit... for which you need cables and counterweights for the whole sash. If you try to make it a side opener only you are going to need multiple tracks and multiple panes of glass to slide back and forth, and this will be inconvenient at best.

I am potentially concerned about the use of epoxy in an environment where there will be nitric acid. I am not sure which epoxy is in use here, but if it has aromatic rings, they could potentially be slowly nitrated over time as you use the hood for refining and you just might end up with a fume hood that is explosive. Try to look up what type of epoxy you have.

Make sure that your building is capable of handling the air influx that air efflux from the hood will require. Consider what this will do to your heating costs. If you have a furnace in there maybe this won't be an issue...

For a scrubber... What you want is a high surface area, so something with an internal shape like a rigid coffee filter would be good. Sodium carbonate should be adequate to take care of the acid fumes, and ground sulfur should capture any heavy metal vapors (aka metallic mercury). I would try to make something that fits right up inside the pipe(s), so you can change it out regularly with minimal hassle.


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## Noxx

Hi Chemist,

My fume hood won't open from the side. It'll open like a regular fume hood, the door being supported by counterweights.

I have an airflow meter and can get accurate reading.

I can understand your concern with epoxy. I'll look carefully.

The air influx was considered in the design, I'm pulling air from the roof which is a few degrees hotter than the outside.


Thank you


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## chemist_12

Ah, so you aren't done building the frame yet. I look forward to seeing the sash and counterweights installed then!

I believe most of the hoods I'm familiar with are built of painted steel. I think a lot of building materials could be good... glass plate would make a pretty great countertop, and so could any number of acid/base/halogen stable materials. An old lab benchtop would be great too, and I bet you could get one used pretty cheap (or free) if you looked around. You could even refinish it with a sander before installation. HDPE Polyethylene would be safe, lightweight, and durable. (think about what chemicals are stored in).

I will continue to watch this project with interest and see how everything works out. Fume hoods are a good idea in general, and of course the commercial ones are expensive, so anyone who is interested in starting up any kind of chemical industry can learn from your successes and mistakes here.


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## Noxx

I started building the second fume hood for my propane furnace. It's all stainless steel.

First time for me welding a project like this. The welds aren't pretty since I do not use gas protection with the MIG.


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## Palladium

Noxx said:


> First time for me welding a project like this. The welds aren't pretty since I do not use gas protection with the MIG.



I remember my first welds. :mrgreen: 
Looks like your doing great Noxx. I love the fact you are so hands on with this project. Watch those welding fumes though.


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## kuma

Hi Noxx , how are tricks ?
I hope that your all well!
That's looking good so far chief , nice work!
I've been following this thread from the start and it's very cool _seeing the magic happen_ as it were , I can't wait to see it all when your finished with the fabrication , 8) 
Wishing you all the best with it , and sending kind regards ,
Chris :mrgreen:


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## publius

Noxx said:


> Snip... First time for me welding a project like this. The welds aren't pretty since I do not use gas protection with the MIG.



I expect that you are using the FCAW (flux core arc welding) rather than the GMAW (gas metal arc welding) referred to as MIG (metal inert gas) in Europe. If that is the case, make sure that the flux/scale is removed from where the weld may contact air that has a high moisture/acid content.


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## buckdec

Just grab some silver and braze it together then when your done with it you can refine it.


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## Noxx

More pics


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## Barren Realms 007

Other than the excessive amount of welding you will be doing it looks great. Excellent job there Noxx. 2 thumbs up to you on this project.


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## Noxx

Nah, I won't be doing to much welding. The empty spaces are sealed using aluminum tape.

Again, I used a system of pulleys to lift the hood at the correct position before installing the chains.


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## glondor

Looks good tho I must admit when I see it it reminds me of french fries and burgers for some reason


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## Noxx

Finished the installation tonight:

Also, had some bad luck trying to install the glass door on the fume hood...  It slipped and broke into zillon of tiny pieces...


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## butcher

The exhaust hood looks great, the glass looks bad.


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## Anonymous

There ya go Nic,now you have some silica for the next smelting batch...lol.


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## Geo

dang, that is some bad luck. next time hire an extra set of hands. i imagine that glass is heavy.


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## Smack

Damn dude that sucks, at least it was tempered.


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## HigginsMechanical

Noxx said:


> More pics




Very nice hood Noxx, sorry about the glass though.... Two steps forward, one step back but keep marching on!


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## DONNZ

I'm lost:

Will the hood be used as a dual purpose hood, fumes and excess heat from furnace and fume removal from chemicals? 

Pic 1 shows the hood hinging

Pic 2 showing your furnace under the hood

Pic 3 showing what look like your work table ? located under the hood ?


How will you move the work table out from under the hood. I see the furnace on wheels, no problem there.

Just asking

The hood looking good, glass not look good at all. 

Adding a question: Why heavy glass?


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## Thinksilver

Just wondering where you got the blower and the cost of it?


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## Smack

Thinksilver said:


> Just wondering where you got the blower and the cost of it?



Re-read page 2 of this post.


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## devala

Greetings! I have not posted before, but I have been reading for several weeks now. This forum is by far the best on PM refining I've seen anywhere on the web, bar none. Thanks to all that have worked so generously in bringing this information together in one place and sharing it so freely.

I was looking into some DIY hood designs, after reeling from the very high prices on pro hoods, and I came upon this thread. I've been intrigued by the Venturi designs some of you have proposed, but I have some concerns about face velocity. In doing some research today I came across these Allegro blowers, both axial and centrifugal, and I was impressed by the design, cost, and high output of these units. I wanted to share what I've found and ask for your feedback concerning the feasibility of using one of these for a DIY fume hood.

--------------------------
Allegro Axial Blower 1842 cfm 12" $375 + s/h 

http://www.ebay.com/itm/Allegro-Axial-Blowers12-Plastic-Blower-/190543729570?pt=LH_DefaultDomain_0&hash=item2c5d4a93a2#ht_1202wt_925
--------------------------
Allegro Centrifugal 3/4HP 1570 cfm 8" $850 + s/h:

http://www.wayfair.com/Allegro-High-Output-Centrifugal-3-4HP-Electric-Blower-9504-50-OAO1171.html?refid=GPA49-OAO1171&gclid=CNH6iZysz64CFWwGRQod9RNbWg

Only $550 + s/h on eBay:
http://www.ebay.com/itm/Allegro-Axial-Blowers12-Plastic-Blower-/190543729570?pt=LH_DefaultDomain_0&hash=item2c5d4a93a2#ht_1202wt_925
--------------------------

These blowers are described as chemical and corrosion resistant, but I believe they all have ABS housings. I'm not sure about the inner materials, but while ABS is very resistant to HCL, it is not at all resistant to HNO3 and H2SO4; so I was thinking these might not be suited as inline blowers but that they could be low cost, high cfm candidates for the Venturi designs being discussed here.


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## devala

Here's another possibility:

Allegro Venturi Blower $450 on eBay:

http://www.ebay.com/itm/Allegro-Industries-9518-08-14-1-4-in-diameter-Venturi-Blower-BRAND-NEW-/280836508901?pt=LH_DefaultDomain_0&hash=item4163290ce5#ht_724wt_1141

From Allegro:
http://www.allegrosafety.com/

The Venturi Blowers are a perfect solution to moving air in refineries, utility and power plants, shipyards, paper and pulp plants, the marine and steel industry and manhole operations. Anywhere where fumes that may be poisonous, explosive or hazardous from process towers, tanks, large pipes or confined space need to be removed. You can cool workers in elevated temperature conditions, or heavy equipment. Our line of high-performance, lightweight Venturi Blowers help to create a safe, healthy working environment leading to greater efficiency and productivity. Welding fumes, hot air, gases and smoke can all be removed quickly and easily.

Compressed air or saturated steam is the power source for our Venturi Blower line. Small volumes of high velocity air (from the compressed air source) run through the casting and out the nozzle jets, creating a venturi action or pulling action that creates large volumes of air through the venturi and out the air diffuser.

A 1/2” hose with a “crows foot” connection is recommended from your air supply source to the side inlet connection. The compressor size required can be determined by checking the chart on air consumed at various inlet pressures. Operate this Venturi Blower on air or steam lines limited to 140 psi.

Choose from Metal or Anti-Static Plastic Linear Low Density Polyethylene (LLDPE)
Lightweight construction
Convenient carry handles for one-person portability to any location
No guards required
Multiple inlet ports
Sturdy steel galvanized steel diffuser
All models include a crow’s foot inlet connection
Static ground is attached to the base of all blowers

These require compressed steam or air as the power source, so a steam generator or air compressor also would be part of the setup, plus an external blower on the roof perhaps. What I like about the steam approach, assuming it could work, is that the gases are diluted with steam before exiting the stack, and it may even be possible to alkalinize the steam before it contacts the gas, thereby moving the fumes and scrubbing in one operation.

Here is a 24KW 3PH steam generator for under $800, but there is no information given concerning the steam pressure it provides; so it's unknown if it could power the Allegro Venturi blowers. Steam generators get expensive quickly with increased capacity, so the steam approach could be impractical if the steam velocity requirements necessitate too costly a steam generator. But assuming this is possible then perhaps an alkaline solution (weak NaOH) could be fed with the steam into the Venturi blower using an inline aspirator, like an airbrush. If one then used a method of in-process scrubbing, like 4metals has described, or in-process gas recycling, as several members have discussed, then the quantity and strength of the fumes entering the hood would be greatly reduced, so that what finally comes out of the stack is PH neutral and fairly clean. 

http://www.ebay.com/itm/24-KW-STEAM-GENERATOR-SHOWER-SAUNA-BATH-HOME-SPA-/320654311499?pt=LH_DefaultDomain_0&hash=item4aa87c804b#ht_2641wt_925

Even if using steam is not doable, it may still be possible to inject alkaline into the Venturi blower using compressed air. The spec for the Venturi blower indicates line pressure of 140 psi or less, which can be maintained easily using a medium sized tank, and air compressors are relatively cheap.


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## devala

Um, strike that last bit about air compressors being relatively cheap. It looks like an 75 cfm or higher compressor would be called for, and these are not at all cheap!

For instance, to get more than 2000cfm using the 9518-16 (plastic) blower requires a minimum 73 supplied cfm from the compressor, if I'm reading the allegro site correctly. Goto 
http://www.allegrosafety.com/ 
and select Venturi Blowers from the side menu.


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## Noxx

It takes a lot of energy to make steam... Also, it's harder to control your fan. With my AC drive, I can dial 5% for the night then 100% when I operate both hoods.


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## DONNZ

All kind of options out there one can draw from when setting up a vent system. Woodworking, plumbing, etc.

Inductor 4 in. In-Line Duct Fan
http://www.homedepot.com/buy/building-materials/heating-venting-cooling/inductor/4-in-inline-duct-fan-62960.html

Dust Collection Blast Gates
http://www.ptreeusa.com/blastgates.htm

All kinds of squirrel cage blower out there. Most efficient way to move air. I would adopt one and wire in a rheostat.

http://www.grainger.com/Grainger/blowers/hvacr/ecatalog/N-8sq?ef_id=8A9O-OjnV3wAAI3w%3A20120306140802%3As&gclid=CJrRw5G50q4CFYwj7AodbQ1iDA

PVC clean outs would work well when connecting two systems together. Look around, you have options. 

I could do a drawing on this type of layout. Would need to know if it has a filter.


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## Plasticman

Hi everyone just thought I'd give my professional opinion. I don't process any ore myself, but I design and build Assay Fume Hoods for big mining companies up in Canada. You can build your hoods and complete exhaust systems including fans and scrubbers using PVC. We've built them for 40 years or so from type 1 grade 1 PVC which you can buy from many distributors in every major city. With a little creative ingenuity you could line any wooden hood with this and extend the life of your hood. If you are using hotplates inside the hood, ensure that you have at least 100 to 125 CFM face velocity at the hood or you could start to burn the PVC. 6' hood should need a 1000 to 1500 cfm blower/fan, depending on the size of opening, ducting, and amount of elbows in the system.


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