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Cheap Laminar Flowhood any good?

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It's difficult to say without knowing details of the design.

For the output to be laminar it will need internal flowguides between the prefilter (if it has one) and the HEPA filter. Without the internal flowguides it will more than likely deliver a turbulent output.

Maybe shoot him a message and ask for more details.

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The response I received which didn't quite address the question:

I would suggest for agar work at minimum a 64 x 32 unit (in the lets grow mushrooms DVD he uses this sized unit)
I use the 91 x 64 at home as I do allot of bulk runs of bags and agar plates

With airflow turbulence we use barrel fans that deliver air at a constant rate into the box
They also do not blow air directly towards the filters to assist with this

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I too looked at these flow hoods but the thing that throws me off is that they aren't professionally made so you can't guarantee that your air flow will be sterile. Check out the places that sell second hand scientific equipment.

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I uses to have a pretty good glove box but I'm over those.

so these are home made? I think that's what they are. I could do that myself...

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If they were professionally made they should have been smoke tested to verify that the flow is actually laminar and that there are no leaks.

Without any such tests I think selling them as laminar flow units for such a purpose is really pushing the envelope.

You could smoke test one yourself and try to identify a suitable area of flow, but it would never be considered for serious lab work.

If you have a small area such as a converted closet or a small room where you do your work , it would still have its place though. You could run it for 1/2 an hour prior to commencing your work to clean the air up, then turn it off and do your work in a tunnel or simple still air box with easy access. It would get you out of glovebox hell and help reduce the spore load in the environment where you are working.

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so homemade glove boxes and laminar cabints really arn't worth the trouble?

Edited by Dreamwalker

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If I were to buy one of these ( if I needed one) I would build this a contained unit that had a perspex hood will a smaller opening at the front for your hands to go in -To keep air leaving the box. I would also like and a prefilter - and maybe some kind of laminar creating filter before the air filter. But with the clean box approach you would probably not need it.

Edited by watertrade

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The guy reckons he works in front of one doing agar work and grain transfers. I'd basically only be interested in it if I could set it up at a desk spray cleaned in a small room and work in front of it while it is blowing - otherwise I'll just make a better glove box I guess...

the idea I had was making it like a flow hood by trying to build a desk surface this blows down into.

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A "sneeze shield" on the front would be a nice addition to that design.

You can probably make one for around as much money but I'm betting you will wish it was bigger. Its possible to work in even tiny spaces (as the results of many GB workers have proven) but adequate room to move is a huge plus if a person is doing very much work.

I built a LFH out of a 22x18" MERV16 Hepafilter, a prefilter, a 465 cfm squirrel cage blower, some sheet metal for an internal air guide to reduce turbulence and a piece of plywood and used it up until last year when upgrading to one of Stamet's larger ones. Never had any problems with the homemade one but having more room to work really rocks.

There are lots of great discussions and teks online. The shroomery in particular was really helpful in getting me an understanding of what I was doing and why (before I started building it)

That said, SallyD's comments are important to reflect on. Its readily possible to build a LFH that contaminates your work or for one of many reasons does not work right for you.

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SallyD, what are your thoughts on the flow hoods offered by Fungi Perfecti? I'm not sure if they include internal fins. I was under the impression that Stamets advocated turbulent air rather than still air for the lab environment, but those comments were probably limited to lab air flow rather than laminar air flow. Also check out the following link with the pictures at the end regarding building a laminar flow hood. Seems to me that this would also not be considered "laminar" by any means. www.fungifun.org/English/Flowhood

It would be great to see some pictures of home built LFH's. Anyone willing to share? designs, thoughts... or other resources for purchasing them or components to build them in Oz?

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Some of those look OK, particularly those ones listed as laminar flow hoods, if the fan is perfectly matched to the filters and the volume of the box laminar flow is still theoretically possible without internal flowguides. So a good design may not need them, it would be a rare case though. The rest of them are just scrubbers/air filters which is what the one in the OP really should be listed as.

I can't recall Stamets advocating turbulent air & still air is not used in a lab because of random particles that float about in even the cleanest of rooms.

Most sterile work is done in the laminar flow very close to a high grade hepa filter so that the air passing over the work is of known quality.

Edited by SallyD

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The one I bought from Stamets is basically a simple plywood box with a 2' x 4' (i.e. 61cm x 122cm) filter in a frame on the front. The fan blows straight down into it and the filter is in front of that void and parallel to the airflow. A second 'box' sits over the fan and has a prefilter on the top.

The one I built is similar but has an enclosure sticking out of the front with a small glass window for a top I can see my hands and the work through.

I used a curved sheet metal guide inside of mine as I liked the thought of lessening turbulence. I used perforated metal for covering the filter thinking it would protect it but I would not repeat that or recommend it as it is a waste of time and money.

It sounds fancier than it looks. It actually looks a bit primitive.

While it has served me very well, I sure cringed every time I hit that glass top with the bottom of a mason jar of grain spawn while inoculating 2 kg sawdust bags.

Despite no sneeze shield the greater working area of the new hood has been greatly welcomed. I'm experiencing some turbulence of my own so do not plan to do anything further with the unit until after I've moved or created a new work space.

Both units have worked quite well for me.

I failed to take photos *during construction* but I'll get images posted of both units and will do a sketch of the interior.

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Can I ask another potentially dumb question.

Do you guys use grain spawn to innoculate wood/lignious substrates because it colonises quicker? Just that when I used to work with other wood lovers id innoculate wet cardboard or small wood chips mixed with verm and then use that to mass innoculate large bags of woodchips with bothering to sterilise because wood chips are unlikely to contaminate.

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Alright, who's offering to share a communal particle counter so we can all start testing whos filter is the cleanest? Or how about least turbulent.

SallyD, that's right, turbulent air for the laboratory environment, not the laminar flow design. But as confirmed by trucha, Paul's LFHs are also very basic yet still marketed as laminar, with the buyer being confident that he would have the blower perfectly matched to the resistance of the filters. He does not have sneeze guards or any such thing in his laboratory, just a giant wall of 60cm high hepa filters.

I've often thought a "sneeze portal" would be great, hooked up to a central vacuum tube. It would have to be really convenient of course.

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Some of it likely involves the actual fungi being cultivated.

I think that grain spawn adds some nutrients to the process. For shiitakes this has kicked it off much better than when I've tried using agar or colonized sawdust. For Hericium I've had the best results when using chunks of mycelial mats pulled out of liquid culture with tweezers or else using three wedges of colonized agar added straight into the sawdust bags and then not shaken to mix it.

That cardboard trick you mention does works really well for some of the smaller woodchip lovers.

Something I found really helpful was minimimizing how much spawn I used. I've been doing best when shooting for twenty 2-kg bags per quart canning jar of colonized grain. Early on I was accidently oversupplementing by adding too much grain.

I'd love one of those particle counters but even if we shared costs I'm probably still too poor to participate.

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Can I ask another potentially dumb question.

Do you guys use grain spawn to innoculate wood/lignious substrates because it colonises quicker? Just that when I used to work with other wood lovers id innoculate wet cardboard or small wood chips mixed with verm and then use that to mass innoculate large bags of woodchips with bothering to sterilise because wood chips are unlikely to contaminate.

"When sawdust is supplemented with a nitrogen rich additive, the yields of most wood decomposers are enhanced substantially. Rice bran is the preferred additive in Asia. Most brans derived from cereal grains work equally well. Rye, wheat, corn, oat and soybean brans are commonly used. Flours lack the outer seed coat, and by weight have proportionately more nutrition than brans."

This was written by Paul Stamets in Growing Gourmet and Medicinal Mushrooms.

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Sneeze portal? lol

If you have a cold, or are worried about breathing on your work, just cover your face with a dust mask from the hardware shop. Cost $1

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EBay guy says the fan to hepa ratio is perfect in his and sent me the details. I think I'll give his bigger one a crack when have the $$$

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If I understand right dust masks are intended to keep particles from being inhaled into one's lungs (with variable degrees of ineffectiveness until going to P100)

Surgical masks are used to catch exhaled particulates.

This is my older unit. Staining is a combination of rust and tannins from the bottom of spawn bags after being pressure cooked. When the lab gets relocated I plan to replace the painted wood enclosure on the front for steel as the inability to clean it bugs me.

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Here is the newer unit from Stamets.

I'll be glad when I get the new facility set up so I can get more working room. "Whatever works" has been the philosophy so far.

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I like SallyD's comments on proper use of words. I think I'll start referring to these as "cleaner air hoods" rather than "laminar flow hoods" since I doubt either one produces a real laminar flow.

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Edited by trucha

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You might want to visit www.shoomery.org and do a search for "flowhood build".

A number of DIY plans are posted. The discussions may also be useful to you - or at least they were to me.

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