Stealth Cab Advice

[DanTheReggaeFan]

Hey guys I'm gonna be building a stealth cab for my next grow and am looking for some advice on how to set up the extraction. I've included a pic of the dimensions. I'm not sure if I should use approx 30-40cm along the whole top as a lung room or if I should just use approx 70cm of the veg side and keep the whole 1.8m for flower if that makes sense. I think the pic explains it better than I do.

 

[DanTheReggaeFan]

I'm gonna be using these lights. Has anyone used them themselves? It's gonna be my first time with going LED. Anyone got any thoughts or just advice about the cab in general?

 

[Douglas.Curtis]

Use the whole space for flower, since your lung room is essentially the room the box will be in. No idea on the light, sorry.
Air in from the bottom, out through the top. 'Suck' the air from the box and push through a carbon scrubber, if odor control is what you need. This makes 'leaks' in the system (except between fan and carbon scrubber) fresh air leaks in and not smelly leaks out.

 

[DanTheReggaeFan]

Use the whole space for flower, since your lung room is essentially the room the box will be in. No idea on the light, sorry.
Air in from the bottom, out through the top. 'Suck' the air from the box and push through a carbon scrubber, if odor control is what you need. This makes 'leaks' in the system (except between fan and carbon scrubber) fresh air leaks in and not smelly leaks out.

Thanks man. Do you mean use the full height for flower or the whole thing because I'm hoping to go perpetual with this, that's why it's got the separate veg and flower area? Lung room might be the wrong word. Really I just mean a place to put the extraction system so it will pull air from both areas so I don't need 2 separate extraction systems. The plan is to have intake holes on the bottom to pull air through and then I want to scrub it and expel through preferably one exit hole. All sections in the cab are going to be siliconed in so there should be negative pressure in there as long as I don't make the intake holes too big.

 

[DontStopBelievn]

Using the light calculator at CocoForCannabis, the light seems perfect for the flowering room. Keep in mind that you will need to make sure light from the veg room doesn't get into the flower room. Twisting ducts is a lot more space consuming than a light trap. It's easier to build two boxes (1 veg, 1 flower) that can be connected rather than building 1 box that does both.

 

[DanTheReggaeFan]

Using the light calculator at CocoForCannabis, the light seems perfect for the flowering room. Keep in mind that you will need to make sure light from the veg room doesn't get into the flower room. Twisting ducts is a lot more space consuming than a light trap. It's easier to build two boxes (1 veg, 1 flower) that can be connected rather than building 1 box that does both.

Thanks for the advice. I'm going to be building it all out of ply wood and running silicone along all the edges to keep each section light and air tight. Then was thinking of using some PVC pipes with right angles in them to connect each chamber to the "lung room". What do you think about something like this?

 

[Douglas.Curtis]

Full Height for flower. I would try to make the airflow through the veg room, then flower room, then scrub above the veg room and exhaust. A second thought is to use an external duct and scrubber, much like my first cab worked.

 

[DontStopBelievn]

Is the idea that the ducting space, flower space and veg space will all be separate, sealed rooms? If that is the case, then you should be fine because each space will be piping into a separate room and you have a good deal of space to work with.

I would suggest looking online for grow room ducts. They come with a cloth sleeve to limit light leaks. Dryer ducts have TONS of little pinholes in them that allows light. Use velcro to easily secure them. I use a thin strip of double-sided velcro to cinch ducts and then a larger sticky one-sided velcro to secure them in place.

With the headroom you have, I would do an S-bend of the duct to the veg room, then scrub and exhaust from the veg room.

Two issues I have with pvc for vent pipes is that large-diameter pvc is expensive and the fittings are really expensive. Ducts and velcro are best route, IMO.

Typically, you want passive air vents to be double to triple the exhaust vent size. If your exhaust is 10cm, then you you should have two to three 10cm passive intakes or a similar area equivalent, like a 30cm duct. This is to put less stress on the exhaust fan motor and prevent a wind tunnel type effect.

 

[DanTheReggaeFan]

Full Height for flower. I would try to make the airflow through the veg room, then flower room, then scrub above the veg room and exhaust. A second thought is to use an external duct and scrubber, much like my first cab worked.

Thanks man. Unfortunately the stealth part is really important so everything needs to be contained within the cab.

 

[DanTheReggaeFan]

Is the idea that the ducting space, flower space and veg space will all be separate, sealed rooms? If that is the case, then you should be fine because each space will be piping into a separate room and you have a good deal of space to work with.

I would suggest looking online for grow room ducts. They come with a cloth sleeve to limit light leaks. Dryer ducts have TONS of little pinholes in them that allows light. Use velcro to easily secure them. I use a thin strip of double-sided velcro to cinch ducts and then a larger sticky one-sided velcro to secure them in place.

With the headroom you have, I would do an S-bend of the duct to the veg room, then scrub and exhaust from the veg room.

Two issues I have with pvc for vent pipes is that large-diameter pvc is expensive and the fittings are really expensive. Ducts and velcro are best route, IMO.

Typically, you want passive air vents to be double to triple the exhaust vent size. If your exhaust is 10cm, then you you should have two to three 10cm passive intakes or a similar area equivalent, like a 30cm duct. This is to put less stress on the exhaust fan motor and prevent a wind tunnel type effect.

Thanks for the advice. Yeah each space will be separate and sealed. Do you mean the standard ducting that comes with extraction systems? I already have some of that if that's the case because I've done a few tent grows in the past, I just can't use it in my new place.

I'll keep the advice about the intake in mind. I'm assuming I would only have them in the flower chamber if I'm going from one chamber to the next. Is that correct?

 

[DontStopBelievn]

Thanks for the advice. Yeah each space will be separate and sealed. Do you mean the standard ducting that comes with extraction systems? I already have some of that if that's the case because I've done a few tent grows in the past, I just can't use it in my new place.

I'll keep the advice about the intake in mind. I'm assuming I would only have them in the flower chamber if I'm going from one chamber to the next. Is that correct?

Yeah, just regular dryer ducts. I wrapped mine in duct tape and then reflective tape, which worked fairly well. I just recently did 2 alternating layers of spray paint (black, white, black white) to really seal them from those pinhole light leaks.

So, the way I'm looking at it, you have two choices for venting. Intake to one chamber (flower) then push to other chamber (veg) and exhaust out from duct chamber. Other is to intake from veg and flower, run both to the duct chamber and then have duct chamber exhaust.

I did a quick mockup of what I mean. Example 1 and 2, respectively. Blue circles are intake, yellow bars are air going from one chamber to the other, brown box is the carbon scrubber. This is for purely illustrative purposes.



Personally, I would do the 2nd method. Intake to veg (no need to light proof because veg can take light 24/7), intake to flower (light proof these intakes). Then exhaust both chambers into the duct space overhead, draw through a carbon scrubber and exhaust out the back or up top. I prefer to pull air through a carbon scrubber instead of blowing air through it and most manufacturers recommend this, as well.

The biggest issue with pulling air from between veg and flower is potential for light leaks. Using the duct space as a gap is a good way to solve this problem.

If there is no partition (wall) in the duct space between veg and flower, then you could get rid of the top yellow bar in pic 2 and just S-snake the duct from flower to prevent light leaking in from any exposure in the duct space. Flower chamber is the only place where being light-tight is necessary.

 

[DontStopBelievn]

If you are insistent about moving air from flower to veg (or vice versa), then I would suggest building a light louvre between the two chambers.

A lot of people mistakenly believe that you can slap a light louvre over a vent and keep the same air flow. This is not at all the case. A louvre will drastically restrict air flow because surface area is reduced. If you would like more info on this, I would be glad to help. But to give you a rough idea, a light louvre will need 2-4 times the area of an exhaust pipe to have the same surface area.

The below pic is an example of a light louvre equivalent to 3 (iirc) 10cm diameter intakes. (apologies for inches, I'm in USA. quick conversion is multiply by 2.54 for metric) The more layers, the more light blocking, but you should be fine with 4 layers. You can get fancy and use wood, or simply use cut carboard strips secured with duct tape and glue.

 

[DontStopBelievn]

I rendered out your drawing into Adobe Illustrator. You might find this useful to print and mess around with. Everything is in 1:10 scale (print will shrink it slightly, but perspective should be maintained), skew is 6cm up, 6cm right.

I think this design would be advantageous. I can flesh it out later as to why.

 

[DanTheReggaeFan]

Yeah, just regular dryer ducts. I wrapped mine in duct tape and then reflective tape, which worked fairly well. I just recently did 2 alternating layers of spray paint (black, white, black white) to really seal them from those pinhole light leaks.

So, the way I'm looking at it, you have two choices for venting. Intake to one chamber (flower) then push to other chamber (veg) and exhaust out from duct chamber. Other is to intake from veg and flower, run both to the duct chamber and then have duct chamber exhaust.

I did a quick mockup of what I mean. Example 1 and 2, respectively. Blue circles are intake, yellow bars are air going from one chamber to the other, brown box is the carbon scrubber. This is for purely illustrative purposes.

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Personally, I would do the 2nd method. Intake to veg (no need to light proof because veg can take light 24/7), intake to flower (light proof these intakes). Then exhaust both chambers into the duct space overhead, draw through a carbon scrubber and exhaust out the back or up top. I prefer to pull air through a carbon scrubber instead of blowing air through it and most manufacturers recommend this, as well.

The biggest issue with pulling air from between veg and flower is potential for light leaks. Using the duct space as a gap is a good way to solve this problem.

If there is no partition (wall) in the duct space between veg and flower, then you could get rid of the top yellow bar in pic 2 and just S-snake the duct from flower to prevent light leaking in from any exposure in the duct space. Flower chamber is the only place where being light-tight is necessary.

I was originally leaning towards something like the 2nd example but without the section above the flower room. Is there a reason I need that section or can the flower room vent straight into the room with the carbon scrubber? Also what do you think about the intake coming from underneath? Stealth is really important so I'd rather not have any holes on the sides if I can help it.

I don't think I will use a louvre just because I already have ducting so I'll just do an S bend with that but thanks for the info.

And thanks for the render it will come in handy. I would have scanned the drawing but I don't have a scanner.