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Guerrilla
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Could the racks I use with my flow hood be causing contam?
#27310734 - 05/16/21 05:59 AM (2 years, 8 months ago) |
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So I’m using 2 racks side by side for my flow hood.
My agar pours are virtually contam free, although when I did a pour of around 60 plates, I numbered the stacks, and stack number 2, the one closest to the point in the middle where the 2 racks join, there seemed to be a lot of contam in this stack whereas the rest were fine.
When I am making transfers or having things open for slightly longer is where I run into issues.
I’m not sure if it’s possible that
1) Contams land on the middle piece where they connect while I’m working, and then blow off into my work.

Or
2) Because the racks go past the point of the air filter. I’m not sure if air from outside the laminar flow could run across the rack.
-------------------- Being pissed on does not make you a real man.
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RogerRabbit
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Re: Could the racks I use with my flow hood be causing contam? [Re: Guerrilla] 2
#27310856 - 05/16/21 08:05 AM (2 years, 8 months ago) |
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Quote:
2) Because the racks go past the point of the air filter. I’m not sure if air from outside the laminar flow could run across the rack.
Yes, it can.
This is how carburetors work.`The flow from the hood creates a low-pressure area which sucks contaminants into the flow. Try to always work in the middle of the hood, but never within a few centimeters of the edge as contaminants can be drawn into the edges. RR
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Guerrilla
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Re: Could the racks I use with my flow hood be causing contam? [Re: RogerRabbit]
#27310890 - 05/16/21 08:33 AM (2 years, 8 months ago) |
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Thanks RR - I'll have to work smaller until I find a more suitable rack. Hopefully I'll see a decrease in contamination now.
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sandman420
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Re: Could the racks I use with my flow hood be causing contam? [Re: Guerrilla]
#27310982 - 05/16/21 09:46 AM (2 years, 8 months ago) |
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These racks are too low.
The table surface is very turbulent
See around 30 seconds into this video
If you continue to use these racks maybe back up from the face of the filter a little more.
Edited by sandman420 (05/16/21 09:47 AM)
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Guerrilla
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Re: Could the racks I use with my flow hood be causing contam? [Re: sandman420]
#27311148 - 05/16/21 12:38 PM (2 years, 8 months ago) |
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Quote:
sandman420 said: These racks are too low.
The table surface is very turbulent
See around 30 seconds into this video
If you continue to use these racks maybe back up from the face of the filter a little more.
Thanks for that sandman. I’ve flipped it over and just using one, reckon it’s ok?
-------------------- Being pissed on does not make you a real man.
Edited by Guerrilla (05/16/21 12:39 PM)
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sandman420
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Re: Could the racks I use with my flow hood be causing contam? [Re: Guerrilla]
#27311213 - 05/16/21 01:34 PM (2 years, 8 months ago) |
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Yea that looks like it's all the way up in the flow. I think the lowness combined with the 2 next to each other was creating a path for eddies of air to come up.
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Inthepit
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Re: Could the racks I use with my flow hood be causing contam? [Re: Guerrilla]
#27311221 - 05/16/21 01:40 PM (2 years, 8 months ago) |
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How far is the rack from the edge of that tape on the hood?
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Guerrilla
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Re: Could the racks I use with my flow hood be causing contam? [Re: Inthepit] 1
#27311223 - 05/16/21 01:43 PM (2 years, 8 months ago) |
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That's good news - I've been thinking my flow hood was buggered or not cranked high enough for a while. Thanks once again, I tried to give you a rating but see you opted out :-)
Quote:
Inthepit said: How far is the rack from the edge of that tape on the hood?

Usually have it 2-3cm away. Further back?
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sandman420
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Re: Could the racks I use with my flow hood be causing contam? [Re: Guerrilla]
#27311242 - 05/16/21 01:57 PM (2 years, 8 months ago) |
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Yes, you should be about 10-15cm or so away from the filter at least.
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Guerrilla
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Re: Could the racks I use with my flow hood be causing contam? [Re: sandman420]
#27311248 - 05/16/21 02:01 PM (2 years, 8 months ago) |
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Shit man ty. What angle should a lighter's flame be at around 10-15cm?
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sandman420
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Re: Could the racks I use with my flow hood be causing contam? [Re: Guerrilla] 1
#27311270 - 05/16/21 02:26 PM (2 years, 8 months ago) |
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about 40-30 degrees on my hood, mines on the faster end of the spectrum.
Edited by sandman420 (05/16/21 02:26 PM)
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Inthepit
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Re: Could the racks I use with my flow hood be causing contam? [Re: sandman420] 1
#27311335 - 05/16/21 03:03 PM (2 years, 8 months ago) |
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Quote:
sandman420 said: about 40-30 degrees on my hood, mines on the faster end of the spectrum.

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