plexiglass

[Mr.Nugg]

does plexi glass absorb light that my plants need? im using it as a heat barrier for my lights.

 

[CaptainTrips]

It will reduce the amount of light, but so does glass. Better that than excessive heat, also plexiglass won't take much heat before melting, although it should be fine with lower wattage bulbs.

 

[reckon]

it all depends on the grade/manufacturing process how much light gets absorbed traveling through the plastic

Extruded sheets are wavy in overall thickness, so yes, they will distort/absorb more light than cast or machined acrylic (plexiglass is just a brand name)
Cast acrylic is nearly perfect in optical clarity, I worked as a plastics fabricator for many years, and one place I worked at made lenses for military applications, and all we used was cast/cnc machined/polished acrylic

acrylic melts at very low temps, and will warp and distort at boiling temps (200F + degrees), so I'd go with cast POLYCARBONATE sheet instead, in say 1/8" thickness.
make sure it's NOT coated with anything or designed for outdoor use (they have UV screens in the plastic mix for outdoor/window replacement polycarb) polycarb will withstand temps over 400F degrees.
now if you have an HPS or MH light, you'd HAVE TO go with tempered glass, as those lights will generate temps WAY over 500 degrees close to the bulb.

ALL glass/plastic will absorb some light, but you can usually get the light closer with a heat barrier so it's a fair trade off IMO

 

[CaptainTrips]

Low wattage HPS/MH can be used with acrylic... I have a dual fixture 175w halide that shipped from the factory with an acrylic shield. Lexan can also be used with high wattage lamps.

 

[Mr.Nugg]

thanks. was jus makin sure. results are comin out nice. will have to post some pics again soon. got a white widdow blooming beautifully

 

[MikeRoOrganix]

very very small amount. keep it dust-free that hurts more