How to stop light leaks

[jojo677]

No, I'm not thinking of duct tape. I'm quite familiar with HVAC. The foil tape you are talking about is hit or miss in my opinion.

Fair enough, I didn't know of the thinner foil tapes. Thanks for the info, you learn something new every day!

As for the baffle, you just need to make sure your air passages are large enough to allow for the airflow going through it. If it gets too large, it may look a bit weird cantilevered off the top box! There are alternative but all use the same general concept of not allowing direct view of the other side.

The alternative would be to do something with smaller baffles, and paint the inside of it black, to absorb any stray light.

 

[jojo677]

Here's another baffle design you could use. Basically any 'baffle' you use is going to reduce your airflow somewhat. I use this design with 6" PC fans to circulate air from my veg to flower area.

I made this from the plastic corner material you use to protect drywall corners, but you could make it from about anything (eg. cardboard, cereal boxes, etc). Then just use a cheap can of spray paint.

The design:

The product:

 

[iwltfum]

I definitely like those baffle designs. What did you connect the frame to the corners with on the last one?

 

[jojo677]

I definitely like those baffle designs. What did you connect the frame to the corners with on the last one?

I tried one using super glue, but it took too long to cure. Then I switched to hot glue! It worked extremely well, and quickly. To evenly space them, I just made 2 spacers the distance I wanted to space them, and worked my way up. Also, I used pieces of the angle around the perimeter, so I had a flange to tape to the frame. I HAD pictures of the construction, but got rid of them...

Maybe I'll put up a tutorial next time I need one, as these things are freaking expensive to buy (like $40 USD each). I made 2 for like $10.

 

[tyshizzle]

I'm gonna try and construct it today if I have time I've been busy but I'll be sure to let you know how it comes along once I've finished

 

[jojo677]

Well, this thread is a bit old, but I had to make another light louver (baffle) today, so I made a tutorial:
DIY Light Louvers

 

[ChangeofIdea]

When it comes to completely blacking out an entire room or even a box... I have been known to have my places so dark at 12:00 you didn't know if it was noon or midnight unless I was on military time... So I will tell you how I make it happen, as I've lived in some places with a lot of windows or even just a room where I slept I wanted completely blacked out. On thing everyone seems to overlook is the seams on the door itself, unless you are using some felt meant to seal doors/windows found at various places for sealing up your house for AC in the summer or heating in the winter.

I have always had a thing about light leaks equals scent leaks, and I don't like either issue when I am in my private room. So I always first start with some plastic, and some duck-tape, don't get the cheap stuff either in a month or two it always seems to start having issues. So I literally buy "Duck-Tape" or some other high quality heavy duty sealing tape. When it comes to plastic, they are not all created equal, and if you was trying to really seal up an area, I go with "Weatherization Plastic" it is so thin, but it will really hold out the heat/cold better than a 10-mil plastic. If you want it to reflect light then I go with a layer of 10-mil black plastic, and then a layer of 10-mil white plastic, if I am hardcore worried about light and smell. You can skip the plastic laying when you make a box if your box is made out of wood, I do it in rooms because I am sealing it up.

Finally I care about light and smell, so I go to Menards or some other home improvement store and I buy a product called "Reflectix" which in Hydro Stores they call and IR Wrap, but I pay a whole lot less. The "Mylar" aka Emergency Foil Blanket mentioned earlier, works to reflect heat... BUT IT CAN STILL LET LIGHT THROUGH IT!!! I used to try aluminum foil and then the Mylar over the top, but within 6-month of being exposed to direct light it will eat pinholes of light through it. Reflectix for a 4-foot by 25-foot roll costs about $30 last time I bought some last year, and it is Mylar on either side and has like a Bubble-Wrap in between the two Mylar outer layers. I then tape my joints up with a Mylar Tape, also sold at Home Improvement Stores, and I want to say that is like the most expensive part, to seal up all the seams. I'd stay away from Aluminum Foil, because it doesn't reflect light evenly and creates hot spots.

As yet another measure I'd be taking on your box is to seal the seams with an Aquarium Silicone, not the typical silicone either... it has to be "Aquarium Silicone" because that is non-toxic for water and plants, so you don't end up creating yourself other issues later on. I know it seems like I am cover smell and light, and the reasoning is because if smells can escape I see a problem with light being able to get in, even in the smallest way. The silicone will also help really cut down on the possibility of the light even getting in or out.

Jojo (above) posted a great design for the light trap, but I always make sure I covered the inside of my light trap with a non shiny, non reflective surface. I always go to the fabric store and look for a black material that is soft and fuzzy like a black velvet or black fleece, and then pick up some fabric spray glue from a place like Walmart. I know sound overkill, but that is why when my friends want a completely light proof design they come to me to do it. Light can reflect off from plain cardboard, and even if you paint it black you can still reflect some light, so need to make sure it is a "flat black" if that is how you want to do it.

Finally my final measure to keep light sealed out from the door, is to go out and get or to make a heavy light blocking curtain (I just bought one for less than $12) or heavy blanket even from a Thrift Store. and I cover the door. Really at the end of the day you can either go all out and cover every base to knock out the light and seal it up so tight that no light can enter even if you put it under stadium lights, or do as little as possible and chance a light leak somewhere... and in the end the choice is ultimately yours by how much time, effort and money you stuff into making it dark.

 

[ChangeofIdea]

I wonder if the back pressure from the baffles will minimize the efficiency of the fan though. My exhaust fan is just a whack ol computer fan runnin off a 12v iPhone charger I wired it to

To get around the lowered exhaust pressure leaving, I'd get around it by using a 2nd PC Fan at both ends of the box... and if you really are concerned about the flow add a third fan in the middle of the box to help move the air faster. I have done this design before and that is how I compensated for the possibility of a lower air flow.

 

[jojo677]

Good advice Piggy! I especially like the recommendation about using black, fuzzy fabric to absorb light. That may even work well with a simple 90° elbow or simpler design.

 

[Weaselcracker]

A light baffle box can also double as a sound baffle box, if your fan noise is causing you concern. Sound is deadened by having to navigate through the 90 degree bends, as is light. Having a lining of soft material such as PiggySquishy mentioned also helps kill some of the noise, especially the woosh of the air flow itself. Another material sometimes used is 'egg carton' foam material like the kind used for cheap mattresses. Foam won't insulate against sound, but that 'egg carton' surface impedes sound from reflecting well off of surfaces. The major difference when you are trying to deaden sound is the material used. The basic principle is that sound can't travel well through dense materials. Drywall (Sheetrock) is a good cheap material for this. There are many kinds of dense fibre board that would work well. In my case I just lined the inside of my baffle with black fleece, then tacked some drywall to the outsides because I was too lazy to rebuild the whole box.

 

[ChangeofIdea]

Good advice Piggy! I especially like the recommendation about using black, fuzzy fabric to absorb light. That may even work well with a simple 90° elbow or simpler design.

Actually as we know from our ventilation system, we are actually better off using 45-degree angles instead of 90-degree angles and so if you use a fuzzy material and want to keep your air flow up, you can always do that, because the light doesn't bounce around so much you can go longer in length, fewer sharper bends and still keep the air flow up and the light out.

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Speaking of the foam egg cartons for sound reduction, back in the day when we couldn't afford that I remember hearing that you can take a cardboard, not the styrofoam, egg cartons and either staple them to the walls, put cut up old foam in behind them where the eggs used to sit, or in later years we'd spray foam that area and then staple it up to the walls of our structure. It is really a poor mans was of knocking down the sound but it really worked surprisingly well. If we ran across that thin foam pad we'd attach it to the outside of our box's walls and then cover it in fabric for decoration purposes and even put something on top of it and draw the attention away from the box itself. But I am widely skilled and have a lot more time than money, and scrape together parts from junk to turn it into other things, so this knowledge comes from a lot of playing around and experimenting for a few dollars and lots of hours of time with nothing else to do .