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Some of these posts are very old and might contain outdated information. You may wish to search for newer posts instead.
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Anonymous
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Re: Technical question about filter disks [Re: Baby_Hitler]
#1888274 - 09/06/03 11:17 AM (20 years, 6 months ago) |
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- Post History Deleted Upon User's Request -
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Beers
Stranger
Registered: 05/13/03
Posts: 16
Last seen: 19 years, 15 days
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Re: Technical question about filter disks [Re: ]
#1888510 - 09/06/03 01:24 PM (20 years, 6 months ago) |
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<------ contam
I think medical grade Tyvek is pretty unbeatable.
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MrMaddHatter
Dementia praecox
Registered: 06/07/02
Posts: 1,420
Loc: Everywhere
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Re: Technical question about filter disks [Re: ]
#1888569 - 09/06/03 01:55 PM (20 years, 6 months ago) |
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Here is some info about filter material. LINK Filter types Some commonly available filters are of the following construction : (1) Non woven polypropylene, such as Unicorn type P. (2) Non woven polyethylene such as Tyvek, (3) Laminates of polypropylene non woven and polypropylene membrane such as Celgard, and Unicorn type 14, and Snowpro laminates, (4) Laminates of polypropylene non woven with PTFE such as Unicorn Type B and type T filters, (5) PP controlled open cell foam, and such proprietary filtered bags such as bags by Mycelia of Holland, and some companies in Japan. Non woven PP There are a number of standard commercial production methods employing PP fiber to produce a filter material. Usually the final process is pressing an accumulated fiber bed by heat and pressure under two steel rollers. The controlled temperature and pressure and the quantity per sq. area of resin fiber will give the final pore size and uniformity. This filter is characterized by its pore size will close gradually with increase of temperature. Tyvek and similar PE filter materials Tyvek is a product produced by Du Pont and there are several grades of Tyvek most suitable for use as filters. The best are medical grades, however if one holds Tyvek against light one will see the unevenness of fibers . In practice a difference in thickness also is measurable. Tyvek is manufactured with HDPE, and therefore does not withstand high sterilizable temperatures. Users usually reduce sterilization temperature and increase time to compensate acceptable sterilization. Usually PE bags use Tyvek as filter material, as HDPE material is readily heat sealable on PE bags. Polypropylene non-woven laminated with polypropylene membrane. Celgard is a material first developed for use in battery cell separation applications. There are several grades of Celgard generally used for mushroom bag filtration use. Membrane is a material fabricated so that a thin PP film is incorporated with micron sized holes. This property is utilized to allow breathing of fungus during incubation. The laminate of this PP membrane onto a substrate to give the finished product mechanical strength and machinability. Lamination process is by heat and calendering of diamond pattern steel rollers, therefore a large percentage of Celgard is void of pores and amounts to over 50% of a give area. This reduces efficiency of filtration. Unicorn filter type 14 uses a material similar to Celgard. This material also suffers to a certain extent temperature sensitivity, that is under higher temperatures, the pores of the material closes, but much less than straight PP non woven as described above. Advantage of this material is for such mushroom specis as shiitake, so that during incubation it requires retention of Carbon Dioxide, therefore a reduced pores and low efficiency of filtration are ideal applications. Polypropylene non woven laminated with PTFE. PTFE is a high temperature plastic material and can be fabricated into thin membrane form with micro sized holes. These processes are well documented in numerous patents since 1970s. By laminating with polypropylene non woven this laminate can thus be heat sealed onto PP bags. Because the controlled pore size is on the PTFE, normal sterilizing heat will not reduce or increase the pore size. This laminate is most suitable for use for spawn production.
Edited by MrMaddHatter (09/06/03 02:10 PM)
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Ganoderma
journeyman
Registered: 09/04/03
Posts: 58
Last seen: 7 years, 10 months
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Re: Technical question about filter disks [Re: Beers]
#1888578 - 09/06/03 01:58 PM (20 years, 6 months ago) |
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i think that the filter disks are made out of the same stuff as a H.E.P.A. filter
the filter disks are cheaper when you buy them in bulk
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Autonomous
MysteriousStranger
Registered: 05/10/02
Posts: 901
Loc: U.S.S.A.
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Re: Technical question about filter disks [Re: ]
#1889353 - 09/06/03 07:53 PM (20 years, 6 months ago) |
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You can purchase Tyvek house wrap in bulk at many building supply/hardware/lumber stores. Just call around. Unfortunately when I say 'in bulk' that means enough of the material to wrap a small house. I looked into this a while back and the amount was too great and the price was too high for the little that I would use.
-------------------- "In religion and politics people's beliefs and convictions are in almost every case gotten at second-hand, and without examination." -- Mark Twain
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ahel
ho bag
Registered: 05/23/03
Posts: 124
Last seen: 19 years, 11 months
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Re: Technical question about filter disks [Re: Autonomous]
#1889808 - 09/06/03 11:00 PM (20 years, 6 months ago) |
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you can get plenty of tyvek that youd ever need for free at your local post office
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Anonymous
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Re: Technical question about filter disks [Re: MrMaddHatter]
#1890010 - 09/07/03 12:18 AM (20 years, 6 months ago) |
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- Post History Deleted Upon User's Request -
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Hongosmeester
old sourdough
Registered: 12/12/02
Posts: 246
Loc: East Bay (EAST BAY GREASE...
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Re: Technical question about filter disks [Re: ]
#1890082 - 09/07/03 12:52 AM (20 years, 6 months ago) |
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check this out http://www.geocities.com/amytys/Tyvek.htm and this http://www.pacificstatesfelt.com I bought 30 sq.ft. for $10 with shipping I showed some fp filters to these guys(Pacific States Felt and Manufacturing Co Inc)(pm me for the phone number) and they said that it had to have some special coating. They have an $80 minimum order for a similar product without a finish on it.
-------------------- Don't fuck with me I'm a postal worker;-) A zen master once said to me don't do anything I tell you to do so i did <p><a href="http://www.whump.com/dropbox/other/ujname.html">Get yours</a>.</p> <p>My <a href="http://tinyurl.com/6valr">Unitarian Jihad Name</a> is: <strong>Brother Neutron Bomb of Compassion</strong>.</p> <p><a href="http://www.whump.com/dropbox/other/ujname.html">Get yours</a>.</p>
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Seuss
Error: divide byzero
Registered: 04/27/01
Posts: 23,480
Loc: Caribbean
Last seen: 1 month, 9 days
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Re: Technical question about filter disks [Re: Hongosmeester]
#1893423 - 09/08/03 08:47 AM (20 years, 6 months ago) |
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> you can get plenty of tyvek that youd ever need for free at your local post office
Be careful with that recommendation... the envelope from the post office says the following:
"This packaging is the property of the U.S. Postal Service and is provided solely for use in sending Priority Mail. Misuse may be a violation of federal law."
You used to be able to get a free sample of Tyvek from DuPont by calling the number listed on the tyvek web site.
-------------------- Just another spore in the wind.
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ahel
ho bag
Registered: 05/23/03
Posts: 124
Last seen: 19 years, 11 months
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Re: Technical question about filter disks [Re: Seuss]
#1893557 - 09/08/03 09:44 AM (20 years, 6 months ago) |
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well of course i meant you can use it only AFTER youve sent something in it
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Anonymous
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Re: Technical question about filter disks [Re: Hongosmeester]
#1897753 - 09/09/03 10:39 AM (20 years, 6 months ago) |
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- Post History Deleted Upon User's Request -
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jahcompkilla
who
Registered: 04/17/03
Posts: 13
Last seen: 20 years, 2 months
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Re: Technical question about filter disks [Re: ]
#1903628 - 09/10/03 11:38 PM (20 years, 6 months ago) |
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Here are some sources for the product that I had used before
http://www.allergybegone.com/3mdisairconf.html
hope this helps
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lysergic
Mycophile!
Registered: 06/09/03
Posts: 691
Last seen: 20 years, 3 months
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Re: Technical question about filter disks [Re: jahcompkilla]
#1905779 - 09/11/03 01:55 PM (20 years, 6 months ago) |
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I've never seen a filter disk, but I use autoclave paper made by 3M. The paper is actually polypropelyne that is double thick. It is designed so that instrumentation in the OR may be wrapped with it and autoclaved. The steam penetrates, but water droplets and spores/virii/baterica can't pass through it. It works wonderfully for grain jars.
-------------------- In response to an attack killing 15 American Servicemen PsiloKitten said: Just give em a little more time, the iraqis are making great progress. And this is unorganized. Wait till they get organized.
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Heruuka
member
Registered: 10/15/99
Posts: 333
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Re: Technical question about filter disks [Re: ]
#1990467 - 10/08/03 03:13 PM (20 years, 5 months ago) |
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Tyvek is actually the industry standard vapour barrier in residential construction, at least in Canada. I work with the shit all the time when i do framing in the summer. In fact, i don't know how many of you have worked on residential developments, but there is a staggering amount of "waste" material that usually gets burned in some quiet corner of the site. A lot of the time you'll find PILES of "waste" Tyvek just lying around. If you want to take andvantage of this, just dirty yourself up a bit and ask any of the crews where the "site super" is. When you find him, ask him if you can go through his waste piles and he will almost certainly agree. You'll be amazed at what gets thrown out, on occasion i've found full roles of tyvek.
H
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Twista
Fire it up
Registered: 04/05/02
Posts: 554
Loc: Central Florida
Last seen: 6 years, 7 months
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Re: Technical question about filter disks [Re: Heruuka]
#2005046 - 10/13/03 11:34 AM (20 years, 5 months ago) |
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find tyvek at staples in 9"x16" envelopes. Cut off the glued flap, disconnect the folds in the envelopes breaking the glue and then cut whatever size you need. 50 envelopes go for about $15 but can easily make you 200+ filter discs.
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plura16
ROM3/10 SOLID
Registered: 09/24/03
Posts: 574
Loc: U.S.A.
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Re: Technical question about filter disks [Re: Twista]
#2008161 - 10/14/03 11:28 AM (20 years, 5 months ago) |
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not sure of the cost -- but these look killer -->
http://www.tolas.com/transfertechnology.htm
found thru maddhatters link.
-------------------- - USA -
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motaman
old hand
Registered: 12/18/02
Posts: 6,047
Last seen: 6 days, 9 hours
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Re: Technical question about filter disks [Re: ]
#2008778 - 10/14/03 03:53 PM (20 years, 5 months ago) |
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spunbonded olefin
-------------------- http://heffter.org
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MrMaddHatter
Dementia praecox
Registered: 06/07/02
Posts: 1,420
Loc: Everywhere
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Re: Technical question about filter disks [Re: plura16]
#2008800 - 10/14/03 03:57 PM (20 years, 5 months ago) |
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haha cool it says
Quote:
Select materials including Tyvek?, films and foils
Tyvek.....what a wonderful material.
They would probably not be worth the effort since autoclavable bags can be bought relatively cheap across the net, but they do look cool. Nice find
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