Finally

[NatzTurnazHeadzBustaz]

Man, Ive been reading books and most of the posts/threads on this site seems like an eternity. Ive finally ordered everything I need and it has arrived except the beans. Im going to post some pictures of my veg box. Let me know what U think. Excuse the mess. There still inside a van because I'm going to have carpet installers at my house and cant move them inside just yet. The dimensions are 27"x27"x36" inside diameter

 

[NYC_Diesel x Jack_Herer]

hey natz! looking good man! should be a perfect veg box. How you lighting and ventilating? T5 and cpu fans?

 

[NatzTurnazHeadzBustaz]

hey natz! looking good man! should be a perfect veg box. How you lighting and ventilating? T5 and cpu fans?

I have (2) 20 watt T8's and the cpu fan. Man Doc (A.K.A. NYC_DieselxJH) if it wasn't 4 U taking time with a NOOB like Myself I'll still be searching Amazon 4 Grow Books. Man Thanx A Million

 

[NYC_Diesel x Jack_Herer]

cool, you keep those plants close to the bulbs and flower em at about a foot and you will still be able to keep the nodes pretty tight. plus it should be easy to keep your temps down in there. I think you are smart just going with the two 20 watters to start, always easier to add more fluros if your plants show a little stretch instead of crying over burnt up dead seedlings.

 

[NatzTurnazHeadzBustaz]

cool, you keep those plants close to the bulbs and flower em at about a foot and you will still be able to keep the nodes pretty tight. plus it should be easy to keep your temps down in there. I think you are smart just going with the two 20 watters to start, always easier to add more fluros if your plants show a little stretch instead of crying over burnt up dead seedlings.

Doc, check out the lip that's on the inside of the door. It has a tight fit. Im going to get everything set up and running for a week so I can see if I can control my environment (as far as heat, res.heat, and humidity) b4 placing my babies in them.

 

[NYC_Diesel x Jack_Herer]

looks light tight. Using a passive intake and the cpu fan as an exhaust will give you that negative pressure you want, help keep the door pulled shut and light tight. Good idea wanting to test everything out before putting the beans in, but I think you are going to be fine on temps.

 

[NatzTurnazHeadzBustaz]

looks light tight. Using a passive intake and the cpu fan as an exhaust will give you that negative pressure you want, help keep the door pulled shut and light tight. Good idea wanting to test everything out before putting the beans in, but I think you are going to be fine on temps.

"Light Tight"? Not air tight?

 

[NYC_Diesel x Jack_Herer]

i meant that lip you built for the door, should make it "light tight", as in no light leaks around the door.

 

[NatzTurnazHeadzBustaz]

"Light Tight"? Not air tight?

What do U mean about negative pressure?

 

[NYC_Diesel x Jack_Herer]

picture your box with a hole cut in the back near the bottom for air intake, and picture a hole near the top for exhaust. Now let's say you can and want to vent this box with only one cpu fan because the temps are not going to be an issue and a CPU fan will give you enough air circulation. So you can put this one fan on the lower hole blowing air in, or you can put it on the top hole blowing out. If you put it on the lower hole blowing in, then your airflow through the box will be a positive pressure situation, where you are pushing air into the box instead of pulling. Since doing this increases the air pressure, air will try to escape at the seems and around the door. If you put that one fan on the top hole blowing out, the air pressure in the box is negative. Air is being drawn THROUGH the box by the passive air intake, and the air is not being pushed out at the seams and door, thus negative pressure.

 

[NatzTurnazHeadzBustaz]

picture your box with a hole cut in the back near the bottom for air intake, and picture a hole near the top for exhaust. Now let's say you can and want to vent this box with only one cpu fan because the temps are not going to be an issue and a CPU fan will give you enough air circulation. So you can put this one fan on the lower hole blowing air in, or you can put it on the top hole blowing out. If you put it on the lower hole blowing in, then your airflow through the box will be a positive pressure situation, where you are pushing air into the box instead of pulling. Since doing this increases the air pressure, air will try to escape at the seems and around the door. If you put that one fan on the top hole blowing out, the air pressure in the box is negative. Air is being drawn THROUGH the box by the passive air intake, and the air is not being pushed out at the seams and door, thus negative pressure.

What's best for the plant positive or negative?

 

[NYC_Diesel x Jack_Herer]

neither, air flow is air flow, but negative pressure is desirable in most grows, ESPECIALLY in flower. If you do not use a negative pressure set-up on your flowering room, then smell will leak out since the air will be leaking out.

 

[NatzTurnazHeadzBustaz]

neither, air flow is air flow, but negative pressure is desirable in most grows, ESPECIALLY in flower. If you do not use a negative pressure set-up on your flowering room, then smell will leak out since the air will be leaking out.

So 2 fans of equal size in would defeat this problemo?

 

[DonJones]

Using 2 fans of equal size would conceivably double the air flow but then would give you a slight pressure difference because one of the4 fans will always work slightly better than the other one.

For negative pressure you want an exhaust fan, which gives you the option to duct in through a scrubbeer, odor eater or even just outside somewhere where the odor wouldn't cause problems.

If you us an intake fan pushing air into the box you get positive pressure and then the odor will leak out into the surrounding room even if you try to duct the exhaust somewhere to control the odor.

What makes the difference in positive or negative pressure is NOT the location but the direction the fan blows. You could put the fan at either the top or the bottom and air blowing in will give you positive pressure --which means that what is inside the box will try to escape where ever there is a crack or hole -- and sucking air out of the box gives negative pressure -- which means the outside air will try to get into the box where ever there is a crack or hole.

Which one you use depennds if you want to keep the air and odors in the box inside of it and the exhaust system or if you want to birng fresh air into the box from the outside of the roomand let the air and odors inside of the box leak into the room.

If I have confused you, I'm sorry. Just PM me and I'll try to explain better.

Don Jones

 

[pcduck]

Most growers want a negative a pressure inside the cab so that all the smell gets exhausted out the exhaust vent and not around the door or any air leaks.

For a negative pressure just have your exhaust fan at a higher cfm than your intake whether it be passive or active.

 

[DonJones]

NatzTurnazHeadzBustaz,

In your p[icture it looks like you lined the bottom and at least the left side with mylar. I'd suggest lining the front, back, and both sides with mylar and maybe the top too. I don't think the mylar will be very servicable on the floor
because of moving the pots around on it.

A suggestion that will make your mylar last longer on all surfaces is to glue it down to the surface rather than stapling it. I haven't tried yet to see what kind of glue will stick to it but I use a lot of permatex High Tack from an auto supply store. It is expensive but it sticks to most surfaces and lets you move the material being glued down around a little before it sets. Before I tried gluing it with anything I'd seal the wood so it doesn't soak up the gulue so badly. A water base latex works well for that or a shellac.

Another suggestion, if you are concerned about improving the light/air tightness of the box, and I don't think you need ot worry about it, go to a hardware type store and get a roll of stick on flat foam weather stripping and apply it around the outer edge of the inside face of the door so that when you close it the foam is compressed between the door face and the lip on the inner wall. You could also caulk the seals with any good solid colored caulking. I use a lot of "PL ULTIMATE HYBRID SEALANT + ADHESIVE" in my various projects because it can be applied to damp surfaces, is not clear or translucent (light doesn't go through it easily), is UV resistant, low odor, realtively quick setting and does NOT have any warnings about not using in a submerged location, like the inside of a fish tank or water/nutrient solution reveruoir. I've boght it at both Lowe's and Home Depot.

You've got a hell of a good grow box going there. Congratualtions!

Don Jones