First time, trying to learn :)

[Welight]

@greengenes made a video recently and he spoke about thermal tape being unreliable, and I think he's going to try to get some plastic pieces printed to hold the strips. I also think a guy named woodshed13 on IG has printed something similar for strip builds, if you didn't want to drill holes in each rib of your fixture.

Besides the tape/grease decision, I think you have a great build and I'm excited to see it!

My take on greengenes video was not as you describe, he said he got a poor batch of tape, but his previous supply of tape was very effective, its hard to get the same latte from the coffee shop and have it taste the same day in day out
cheers

[ganjah]

Hey Mark, thanks for chiming in. I'm curious why you thought that was so important to mention it?

Here's the timestamp where gg mentions it and why I wrote what I did.



He speaks about wanting to find someone with a 3d printer to design & print some type of strip clamps to keep them secured to the heatsinks. Why? He said he's had some thermal tape for years that works well, but he bought new stuff that doesn't work as well. Sure, maybe he didn't let it set long enough. However, if he's going to the trouble to make clamps, when for years he's recommended thermal tape, then he must not trust the thermal tape.

Perhaps you have a brand of tape you could recommend that works 100% of the time and is cheap + readily available around the globe? If so, I'm sure we'd all love to hear about it!

[sprout]

wall reflection changes spread dramatically.

I have a Homebox tent that I got used, it has this white reflective inside coating they sell as "PAR+". Panda film? It might not matter with LEDs anyway as infrared output is much lower.

"Test conditions: Using the spectrometer AvaSpec 3648 with probe, the PAR value was measured at 49 points at a distance of 40 cm from a light source. Light source: Adjust-A-Wing Avenger & Super Spreader with Osram PlantaStar 600 Watt and Lumatek 600 Watt, electronic ballast in superlumen mode. The test was carried out in a HOMEbox®, 1.44 m2 PAR+ tent and in a tent with a "silver" interior of the same size from the competition."

[ganjah]

A few things to consider @sprout:

Don't trust the claims of any tent manufacturer. Their reflectivity charts are obviously bogus marketing gobbledygook. Also, IR output in LEDs is so low as to be immaterial to the discussion.

More important, though is hanging height. You want to put these strips as close to the canopy as the canopy will allow. As soon as photons hit the walls, you start losing photons to absorption - how much is debatable and based on your used tent's wall reflectivity, but it's enough to not want any light on the walls in your 20 strip situation, if possible. This likely means hanging 4-6" above the canopy, never more than 12" above the canopy, and making sure your canopy is pretty even via topping, scrog nets, and/or other types of training.

Another thing I'd strongly consider is building two frames of 10 lights each so you can manouver them more easily. From experience, I think you're going to find that one big 45x45" fixture is going to be difficult to work with in a tent, especially when you have multiple plant heights the exhaust fans are sucking in the edges of the tent. Two separate fixtures make everything a lot easier.

And when you build those fixtures, I wouldn't spend any time or effort on spacing the strips irregularly for tiny spread benefits. It makes the build more difficult and isn't worth it if your hanging height is right IMHO. Start by hanging high and at 50% power when the light is new, and then work your way down slowly over the course of 2 weeks to just a few inches away from the tops until they start to complain. Once you figure out the best height for your plants, keep the lights low against the canopy and adjust the output with the driver's built in dimming.

That's my $0.02.

Oh, one last thing. Since your tent is used, beware of light leaks. Even pinhole leaks can cause issues in flowering. Check by putting up the tent, sitting inside it sealed up, and have someone shine a bright flashlight slowly across the whole thing, top and sides, paying attention to the air intake and zippers and seams. Tape them up if you see any light leaks.

[sprout]

Yeah that makes sense checking for light leaks, I'm planning overall test runs. Wall condition is good though, the material is very thick as well compared to what I have seen before. The floor part was damaged and I reached out to the manufacturer, new one is on the way. I'm planning a scrog with 9 plants in aero, veg should be short that way. Thoughts on fimming + low stress training for scrog? Was thinking on training rather early to flower with a short stem for headroom on a sativa dominant hybrid.

[ganjah]

Glad to hear about the tent. That's good service.

Scrog sounds good. I'd suggest running only one or two known phenos so you have consistency across the canopy. Sounds like that's where you're heading. How much experience do you have with training?

For me, training depends on how much headroom I have, and how dense I make the scrog - some use a scrog just to support tall colas that stretch 18-24" above the net, but some use it as the canopy and weave tops in tightly until a week before stretch stops, so the net is all flower tops and there's not much below the net.

I don't like fimming, personally, because it's too inconsistent. I either go with straight topping, or LST weaving. 9 plants in aero in a 4x4 should be a very dense canopy, very quickly, if you start from clones of a vigorous pheno.

I would think in either case, with good defoliation practices, you could get a solid 24" depth of quality, dense flower growth from the top of the canopy on down. Obviously that's pheno-dependent.