foil??

[clowd-9]

whats wrong with useing foil as a reflectent??????

 

[DutchMasterPuff]

whats wrong with useing foil as a reflectent??????

http://www.marijuanapassion.com/forum/showthread.php?p=432588#post432588

 

[The Hemp Goddess]

Foil doesn't reflect well. The following products are more reflective than foil: mylar, panda film, flat white paint, semi-gloss white paint, and flat yellow paint (which is about the same). Flat white paint is probably cheaper than foil, is washable, is easier to "apply", and has far more reflecting ability.

 

[CasualGrower]

Foil was designed to capture and reflect RADIANT energy... HEAT.... yes it will reflect light OK... but with that light it also reflects heat....


That is why you you COOK with it..... you dont grow MJ with it...

Hope this helps..

 

[D3]

Foil does reflect some, but the problem is hot spots. You can get hot spots with mylar as well, just not as easily as with foil. The trick is not to crimp it. It's the crimps that cause the hot spots. If you have ever tried foil, it's hard to put it up without crimping it. Mylar is much eaiser to install. Foil is too hard to clean when needed. Mylar is like cleaning a mirror, it's easy. You will also have a fan in some rooms. The fan will rip foil right off the wall, but not mylar. Go with mylar it's much better. :hubba: Later Man.

 

[leafminer]

"Hot spots" can be caused by either foil or Mylar. They are not caused by "wrinkles" in the foil or creases in the Mylar. They are caused when you don't get the reflecting surface flat, but instead it curls into a concave shape. As you should recall from your physics classes at secondary school, concave mirrors concentrate light and heat energy, but the effect depends on the size of the mirror. Small wrinkles and imperfections won't cause a problem. If you have a large area, say 4" or 10 cm across, that happens to be a concave shape - like a shallow saucer - then that will indeed concentrate light and heat and cause a hot spot.

Shiny side foil reflects 80% according to the published figures, and so does flat white paint. This means that after 6 reflections only 25% of the light remains. With Mylar, (98% reflective) after 6 bounces, 90% of the light remains. That's why Mylar is the preferred reflective media. Provided you cover every surface the photons can bounce around a long time before being converted to heat, and the more bounces, the more chance of encountering a leaf and taking part in photosynthesis.

 

[Alistair]

Rockster once gave a good argument about why aluminum foil doesn't create hot spots. It had something to do with conduction and some other interesting points. Well, after his point had been made none of us could refute what he said. He basically said that foil didn't create hot spots.

Leafminer has some good points too, except, I have always read and been told to use the dull side for reflectivity. Just the same, the others seem to be right concerning it's relatively poor ability to reflect light.

Going from personal experience ( I like personal experience), I always used to use foil and I always had issues with heat stress. For my last grow I replaced the foil with flat white paint and I had no heat stress issues whatsoever. The only "heat stress" that my plants experienced was when I flat out burnt a few tops because the light was way to close to the tops and they got burnt, but that had nothing to do with the classic heat stress symptoms.

Painting the wall is so much easier and nicer to work with. If you really want great reflectivity, try titanium white paint. However, it is rather pricey and flat white reflects at least 75%-85% of the light. It's good enough for me.

 

[leafminer]

Yes, titanium dioxide is the pigment that reflects best, commercially available. Barium compounds have also been found to work as well as titanium but I don't think there is a commercial paint that uses it. (Sorry for that useless piece of information, my head is full of useless info and I have to find some way of using it.) BE WARY of white paint, some still contains lead, check the label!

 

[D3]

leafminer, I read it on the lable the mylar had. "Do not bend or crimp, may cause hot spots". I wouldn't say it if I had not read it. You are right about getting it flat on the wall. If concaved, it will do that as well. It said that on the lable as well. At least the mylar I got did. Didn't mean to piss anyone off.

 

[Alistair]

DLM3, that's interesting.