is 3.5mil black poly lightproof?

[Sicarii]

is 3.5mill black poly light proof? thanks
peace sicarii

[c-ray]

I'm guessing you'd need to double it up

[Sicarii]

ok thanks. what thickness is panda film?
peace sicarii

[c-ray]

I dunno but the standard black & white poly in hydro stores is 6 mil

[memyselfandi]

thickness is not the only variable, the density of the poly is also important.

I use thick poly to cover my tent when i go camping in the winter, sometimes it has small bubbles that let the light pass, but as cray said if you double it would solve the problem

[Bigcanuk]

I use 7 mil black photo plastic. It is avalible in most online hydroponics stores. It can be a tad costly about $50.00 per 10'x100' roll. It is 100% light proof.

[memyselfandi]

a huge detail, the plastic used must be UV resistance