Cheap mylar alternative

Discussion in 'Grow Room Design/Setup' started by budsies, Mar 28, 2012.

  1. So i was trying to find some reflective material that I could buy locally, and rather than spend $20-30 on mylar I found a great cheap alternative. $3.48 for a car window shade from walmart that claims 99% reflectivity. Just lined my cab with one and it looks like it does a pretty good job. anyone have experience with this stuff?
  2. Check the Dollar Store! They frequently have them for a buck!

    Also check Walmart's camping section for mylar "Emergency Blankets". I didn't buy any but I think they are about the same price as the window shades, but are bigger.

  3. Granny beat me to it... I use flat white paint, or black and white poly or 'panda paper' (not really paper :p ) myself, but those emergency blankets are huge and very affordable. Just remember they do help to trap a bit of heat, so be sure your ventilation is good. :)
  4. thanks for the tips you two.
  5. Those window shades and emergency blankets are designed to reflect heat, not light. so that 99% figure means nothing for your purposes.

    Based on what? 1) you haven't wrapped your grow space in "real" mylar to have any basis of comparison, and 2) your eyes perceive light subjectively and thus actually make a poor tool by which to judge light.

    The emergency blankets are even worse at reflecting light because they are so thin that when you hold one up to the light you actually can see through it. Light passing through is light not reflected. There is a reason those space blankets are a couple of bucks and horticulture-grade mylar is $20-$25 a roll.

    Bottom line is: are car shades and emergency blankets shiny? Yes. Do they reflect some light? Yes. Do they compare well to mylar? No.

    Flat bright white paint would do better for you than either that car shade or emergency blankets. White side of panda film also is good. Or bite the bullet and get true, horticulture-grade mylar, it reflects more light than any of the others.
  6. tissue foil cheapest

  7. Yes, but there is also a reason why I didn't get mylar. 1. I'm broke 2. Nowhere to purchase it locally and discreetly.

    I do notice a little bit of light passing thru the shade now that you mention it. but as opposed to the silver wrapping paper I was using before, this seemed like the best option.
  8. Flat bright white paint would reflect more light.

  9. This.

    I made the rookiest mistake when I was assembling parts for my test grow. I did aluminum foil, Reynolds owes me at least a share worth of stock lol. I even went shiny side out. I spent HOURS hanging and rolling it out to get it flat as possible. Took me longer and cost more to foil my closet then to just flat white paint it.

    I'm still learning and getting ready, been talking with another local grower. He grows for himself and his 5 patients as a care giver. He said he used to use mylar, he's in a wheelchair and grows in soil, cleaning and replacing when too "used" was a big cost. He said to use any latex based flat white, which Lowes has Olympic brand for like $12/gal. for regular flat white and I think $20/gal. for the flat ultra pure white. He used the ultra pure and said he has not seem any real difference in yeild or quality.

    I like the Behr one and is what I will be using in the next week. It's a touch more then then cheap Olympic, resists mold/mildew, self-priming (makes painting easy), good white pigment for covering (one coat should do it) and durable. I may just make a false floor and coat it in this or roof coating. Here's the link.

    BEHR 1 Gal. White High/Hide Barn & Fence Paint 03501 at The Home Depot
  10. awesome thanks!

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