why can't you use the cracks in the edges of your cab as an intake?

[Guest]

I have cracks on every edge of my cab that I haven't sealed with weatherstripping, and was wondering why can't I use those as passive intakes, is it since passive intakes have to be at the bottom? and odor will escpae?

also about darkroom vents is there something you have to do to open them, it looks completely closed. I guess since it's a darkroom vent it's like that to keep light out, is that correct?

 

[bostrom155]

I have cracks on every edge of my cab that I haven't sealed with weatherstripping, and was wondering why can't I use those as passive intakes, is it since passive intakes have to be at the bottom? and odor will escape?

If the box is in a dark room during dark times it's ok, but if thiers a light on during thier night cycle your screwed, seal that shit up. The little bit of air is not worth a hermie, just add another hole if you need it.

 

[HappyHemphog]

#1 - Light will escape the cracks. Possible security issue.
#2 - Insufficient flow. It will probably not be enough flow.
#3 - If you have a fan sucking the air out of the cab, it will whistle like a motherfucker going thru those cracks.

Word of caution, placing intake vents near the floor isn't the best idea. The floor is where you find most of your mold spores.

My cab intake is at the top and goes down a 4" PVC pipe to the bottom of cab allowing the air to then flow back up thru the cab removing any heat as it goes along.

Cheers!

 

[Guest]

It really depends on you setup, if your closet is in a private room with the lights off the then yeah take the stripping off, flowering during the daytime eleminates daytime activity conflicts.
I think the occasional light leak does not lead to a full blown hermi but can leave a few claws in your bud near the end.....they smoke fine.
Remember that you need twice the intake surface of the exhaust, eg 6" exhaust----> 2 x 6" holes for passive intake.
I have my passive intakes 6" from the floor and have 0 problems but I keep my room spotless and my door trims are unsealed, I did find it restrictive to rely only on the door crack space when I tried it.

 

[Jnugg]

Abcdabcd,your using a 250 w HPS or a 400 w HPS?also what size exhuast fan?And is it a mills pride cabinet?

If you can raise the cab a few inches off the ground then continue reading this reply.

Check it out.Go to Home Depot or Lowes and pick up a 2.75" Hle saw (hope you have a drill) and 4-6 sections of 12"18" long 2.75" outer diameter PVC tubes and 8-12 2" inner diameter pvc 90 degree elbows.

Inside your cab at the floor board of the cab drill/saw the 2.75" holes around the edge (about 1-2" from the edges) and place 2-4 of the pipes in and connect the elbows (the elbows act as light baffles) and seal all cracks with cualk and use weather strippeing to seal the doors and any other cracks from the doors.If you are using Darkroom vents (which I suppose you are) then place them on the opposite side of the cab from the exhuast and place them a little off the bottom of the wall.Seal all cracks with cualk and weather strip the doors.

If you were to keep those cracks and not seal them you could have major problems when you hit flowering stage.MJ plants need an uniterupted dark cycle of 12 hours and any light that gets to the plants during this 12 hours will slow down/retard the flowering process,you could end up with plants that stretch and stretch and stretch,fluffy not worth your time buds not too mention the fact that you risk the possibility of turning them hermie.

 

[Guest]

This total darkness thing is so old....plants outside finish perfectly despite multiple dark cycle interruptions like moonlight ans such, they finish with no problems.
The real problem is HID's closeby where alot of light comes through the door, not a little light from say tabletop lamp at the other end of the room.
In not saying total darkness is not best, I'm saying it's overstated how essential it is.

 

[Guest]

damn my exaust is 8x8 so I need to add 2 - 8" intakes? and I can only add them on the sides, if I add them through the top and to the bottom, it will take up space for plants since my cab is only 2x2x4 (ft), it's not a mills pride cab, it's a 250W HPS with a 4" vortex.

maybe I over did the exaust, should I cover it up and add a smaller 4" exaust? since my cab is only 2x2x4 (ft)


also about light escaping, cab is in the closet, and dark period would be at night and I can cover the bottom of the closet with a buncha stuff, but I'm going to add weatherstripping anyway

 

[Guest]

yup, I use a 6" exhaust hole for an elicient and have 2 x 6" holes at the base of the closet door and that's it.
A 4" is fine but you won't be able to upgrade to a 400W if you feel the need, you can put ther fan on a ceiling fan dimmer if it is too strong.

 

[2buds]

Edit: Worthless info there.
The black silicone is great. If you run the light on a seperate air system you'll cut your heat issues alot. Just remember that the radiated heat from the light will still exist but the billowing heat from the hood will not. as for the cracks, seal them up, you want to control your airflows intake exhaust. I can agree that 100% darkness isn't the end all be all of flowering but indoors, you never know when you need something from where your grow is so plan ahead to be able to work around your grow in dark cycles and not affect what's inside your cab. Stay green, stay safe, peace.

 

[bostrom155]

damn my exaust is 8x8 so I need to add 2 - 8" intakes?

I thought your INTAKE was the 8x8 louver, your exhaust is the 4" fan your using, right?

 

[Guest]

I thought your INTAKE was the 8x8 louver, your exhaust is the 4" fan your using, right?

yes you're correct, ok I see I'm confused, but do I still need to add intakes? it seems if I have that 8x8 louver and exaust is the 4" vortex, am I ok? or do I need to add additional intakes?

 

[bostrom155]

Ok ABCDABCD.I will attempt to explain this in a manner you can understand ok...ok.
You have a bedroom.In the bedroom is a closet.In the closet is your grow cabinet.
Leave the fucking closet door open or make sure there is atleast a 2" gap between the bottom of the door and the floor.
Turn your air conditoiner on and set at 70 degrees F.
Place your light in the cabinet.Plave the fan outside of the cab and ontop of it.Cut a hole through the top of your cab and run some ducting from the light out of the cab and connect to the exhuast fan.Connect a length of ducting to the other side of the fan and run that either trhough the ceiling into the attic or out of the closet.
You must have a way for air to get into your grow cabinet so you must make intakes (I see you have one darkroom vent).If you do not cool the air in the room the closet that houses the grow cab is in then the grow cab wont get cool air meaning it will not cool the cab.

Warm air coming in equals even hotter temps in the cab.

With a 250 watt HPS and a 4" 170cfm inline you should set the A/C at 70-72F.leave closet door open so the cool air can get in there and be sucked into your grow cab by passive intake.

How many more posts of the sam shit are you going to make?

remember this advice? How far have you come since then? With that size louver 8"x8" = 64 square inches, your exhaust is 4" Pi*r*square, so 4" is 12.56 or so thats 5:1 instead of 3:1 ratio, you should be good on the venting, because thier is a 50% or so drag on the louver its the closest temp dude.

 

[Guest]

well that's good news i don't have to add anymore intakes, but when I close my closet door it gets a lot hotter than when my closet door is open, ofcourse I'd prefer to keep my closet door closed, but I guess it's since all the hot air is being dumped into the closet, so I need a fan outside the cab right?

 

[bostrom155]

You have to keep the doors to the closet open. Period! If you made the cab yourself, do yourself a favor a get a pre fab cabinet like a Mill's pride, it will not look out of place

 

[2buds]

Can you vent the cab to the attic? Put the heat where the heat is already at.

 

[Jnugg]

well that's good news i don't have to add anymore intakes, but when I close my closet door it gets a lot hotter than when my closet door is open, ofcourse I'd prefer to keep my closet door closed, but I guess it's since all the hot air is being dumped into the closet, so I need a fan outside the cab right?

Take the closet door off and shave/sand about 2 inches off of the bootom of the door,this should help you out with that problem.With a proper sized gap under the closet door air will be able to be sucked under the closet door and into your cab via the passive intake (darkroom vents).

Where are you exhuasting the cabs air to,is it just getting dumped back into the closet or do you exhuast to the attic or out of the closet and into your bedroom?