Such thing as a fume hood out the box ready to go?

[Hartbar]

I’ve been looking for a fume hood for metal refining, seen a lot of info on building fume hoods, but not sure if I’m up to doing that to be honest. I’d hate to build one that doesn’t work well and turns out to be unsafe.
Is there such thing as a fume hood that you purchase and can operate safely with minimal assembly.
Thanks in advance for any leads or info.

 

[andu]

You either make it yourself or you toss thousands of dollars on one you can find googling, they don't even write their prices so you have to contact them, which is most annoying. Expect somewhere between 1500-2500 per sq meter.

 

[4metals]

Bel art makes a few.
Fume hood
Not exactly cheap. Actually not even close to cheap!!!

 

[eaglekeeper]

I’ve been looking for a fume hood for metal refining, seen a lot of info on building fume hoods, but not sure if I’m up to doing that to be honest. I’d hate to build one that doesn’t work well and turns out to be unsafe.
Is there such thing as a fume hood that you purchase and can operate safely with minimal assembly.
Thanks in advance for any leads or info.

Look on craigslist in your local area for a "55 gallon barrel/drum". I believe the plastic ones are PTFE and some companies either give them away or sell on the cheap.

I think there's a forum member that posted a picture of a 55 gallon drum fume hood. It's large enough for a single hot plate, but small enough that it wouldn't require an over size extractor fan.

That's what I used when I first started, but only having a single hot plate soon became a hindrance....at least for me.

 

[4metals]

I helped a jeweler set up 3 of these in a U shape all tied into a 8" header and blower. He used one for digestions and parting, one for filtration and dropping the gold, and one for a small silver cell. He cut up extra drums to cut out a door to slide up and down and strips to make tracks for the door to slide in. There is no limit to how many of these you can connect into a big enough header.

 

[4metals]

This hood uses standard off the shelf Home Depot 4" pipe and fittings and
this is the funnel on top

 

[Shark]

This hood uses standard off the shelf Home Depot 4" pipe and fittings and
this is the funnel on top

Any information on the stand used. It really adds a nice touch over a home built wooden platform.

 

[eaglekeeper]

Any information on the stand used. It really adds a nice touch over a home built wooden platform.

I more interested in that gigantic funnel on the top....what size filter paper would that use...

 

[eaglekeeper]

I used the white drum because the blue ones were too dark on the inside. I did add a sealed light in the top but I don't remember what it was.

I just had the duct secured to the flat top of the drum. The funnel on the top is a great idea, probably way more efficient then what I did.

If you can get 2 drums, you can use the other as a stand by securing them together.

 

[speed]

Thing is the enclosure is simple to make. Its the corrosion resistant fans I find impossible to source at a sensible price.

 

[Hartbar]

Thing is the enclosure is simple to make. Its the corrosion resistant fans I find impossible to source at a sensible price.

Some great input, thank you all. Looks like the base is relatively ok to make, as above poster mentions, it’s the fan and duct above that concerns me?

 

[4metals]

more interested in that gigantic funnel on the top....what size filter paper would that use...

It’s a powder funnel so the hole on the bottom of the cone is 4” diameter. It wouldn’t support a filter paper.

 

[4metals]

Any information on the stand used. It really adds a nice touch over a home built wooden platform.

He got that from an injection molder rep. Not cheap for sure and it wastes space under the hood.
I always liked to store waste acid in a 15 gallon drum under the hood in a sealed drum connected to a pipe sticking up thru a bulkhead in the hood drum. The waste drum was on a dolly and we could line up the vent bung on the waste drum with the hole in the 2” bulkhead in the hood base and screw in a 1” pipe to fill the drum. That kept all of the stink in the hood when transferring. The best waste drum for this is translucent so you can see how full it’s getting. When it was full just unscrew the 1” pipe and roll out the drum to process the waste.

 

[4metals]

Thing is the enclosure is simple to make. Its the corrosion resistant fans I find impossible to source at a sensible price.

Corrosion resistant blowers are expensive. No doubt about that. There is a thread about using a regular blower out of the fume path in the DIY section in the library. Click on the link for the library in my signature line to find it.

 

[4metals]

Another use for those powder funnels. This guy needed to dissolve Silver for his Silver cells. A small 3000 oz a week system. The manufacturer of the cell wanted thousands of dollars for a system to do this. All it took was one funnel, one stainless steel pot, and one heat band. Saved a little money!

 

[billgold]

I have always felt that a venturi type extractor system is best. That way your blower is not in line with the exhaust and does not need to be chemical resistant. If a person cannot find a decent design via web search, all they need to do is look at the nozzle for a placer mining suction dredge.

Designing an efficient hood is another matter. An ideal design would be for laminar flow inside the hood.

 

[4metals]

If a person cannot find a decent design via web search, all they need to do is look at the nozzle for a placer mining suction dredge.

The only suction dredge I had first hand experience with was a Keene 6" dredge which I took to Ecuador for playing with placer gold. The eductor was metal. For NOx scrubbing it will not hold up. Do they even make plastic eductors for suction dredges? I'd love to see a link.

Note the 4" line in the photo above went directly into a wet caustic fume scrubber.

 

[Ag and Au]

This company sells assorted used fume hoods - but just the hoods. Installation and testing are seperate.
https://www.americaninstrument.com/pages/refurbished-fume-hoods

 

[4metals]

The hoods on the opening page of that link, metal hoods with epoxy lined insides, really do not hold up in a refinery. Those are great in High school and college labs but in a refinery, where buckets are left bubbling for a full week and NOx (scrubbed or not scrubbed) abounds they don't hold up. I have photo's of clients that have used them and are quite proud of themselves for the money saved. But a few years down the pike, the hoods are disgusting and falling apart. But the last thing I'd want is a client see their disgusting hood show up on the internet. So I save those pictures to show them, in person, how poorly they hold up.

 

[Ultrax]

The most expensive part of the hood is the acid-resistant exhaust fan. Typically, vendors use an industrial polypropylene fan with a sealed motor and bearing protection, and this fan's average cost is about $2000. It is usually inexpensive to make a hood box with glass yourself. We went the other way, and instead of an expensive suction fan, we used a conventional powerful exhaust fan supplying airflow into the Venturi tube. The outlet in the central part of the tube in the exhaust duct forms a powerful indirect vacuum that draws all toxic vapors out. The cost of this fume hood (including installation) is $500.