DIY COB reflectors

pedrovski said:

I notice light is shining through your white painted bottle tops you are using as reflectors, have you tried putting a layer of black or reflective paint before the white? thought maybe that might increase effectiveness of the reflectors.

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SupraSPL said:

Good observation I was wondering if anyone would notice that. When I made the first reflectors I used only one layer of paint. When I added a second layer there was a noticeable improvement in the numbers. But when I added a third layer there were no more gains. I am guessing that even though 3 layers may catch more photons, they dissipate inside the paint layer before they can get back out so it balances out. The reflector in the pic received 2 layers, so the photons we are seeing on the other side are apparently unrecoverable.

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pirg420 said:

Ive got the Ideal cob holders and ledil reflectors, but now i need the Ideal chiplock reflector adaptor, does anyone have a source?

thanks

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pirg420 said:

Thanks Ambiqua, i gotta find some for 3590s though. i cant see any on newark

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SupraSPL said:

AP the lense is supposed to be a 90 degree, but must be wider in practice since I am getting a 15-18" light circle at 10" distance. I consider that a good thing I wold prefer wider than 90 degrees in a lens for my setup.

The reflector is from a 2 liter soda bottle, which appears to start off at a 90 degree angle and then tighten up to maybe 60 degrees. That should lead to an even tighter beam, smaller circle and longer distance to canopy, but in practice it creates an even larger circle, probably because of the scattering effect of the white paint.

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alesh said:

Supposed to be 90 degrees, but
- not made for CXA30XX (try LEDIL site and notice how the angle changes with same optics and different COBs)
- distance between LES and the lens not specified (try changing it - I guess it'd have a noticeable effect on the angle)

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SupraSPL said:

Yep I came to the same conclusion about 3D printing a reflector, better off with a soda bottle LOL. Of course there more sturdy and aesthetic options for DIY reflectors we just have to track them down.

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JavaCo said:

Here is my DIY reflectors. Cut out of a piece of aluminum. Never have to worry about these jokers melting

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JavaCo said:

Here is my DIY reflectors. Cut out of a piece of aluminum. Never have to worry about these jokers melting

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SupraSPL said:

Yes I notice that if I increase the distance between LED and lens the beam gets tighter and eventually will focus an image of the COB. But also I figure as I increase the distance between them, more of the COB is escaping being captured by the lens. So in that case a bigger lens or reflector combo would be helpful.

@draz pointed out that based on the size of my light circle, the beam is probably tighter than 90 but I am confused on that issue. At what lens angle would the distance to canopy and light circle diameter be equal?

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SupraSPL said:

Awesome find thnx @alesh

All good thcammo, I though the same thing but here is what the output of a bare Vero 29 looks like. The COB is pointing at the ceiling, this is the side view. I tried hard to get the exposure to match what my eyes were seeing and I think this is a good representation.

This is a pair of Vero 18s side by side, 16" away from the wall, pointing directly at the wall. One has a lens attached and one is bare. The increase in intensity is 200-300% in the entire footprint. Again it was hard to get the exposure correct because the camera does not have the dynamic range that our eyes do and this picture slightly understates the dim side. But the lux meter numbers show an amazing increase in intensity, more than any reflector I have tried yet. I was not expecting that I figured lenses would be a flop. It took some time and several test results before I could accept it. There are smart DIYers that remain unconvinced, so this is currently a controversial idea.
View attachment 3354650

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nevergoodenuf said:

Has anybody tried cutting and riveting a small reflector from the tin used in standard HPS hoods. Something like the floodlights I'm using. On my 500w led, I replaced the round cone reflector with a modified sunsystems hood. Evened out the light to almost what I want. When I get around to it, I want to change the angle until I get a 4'x4' footprint a 18". Right now I get a 4'x4' footprint at 24". I will be trying different lengths and different angle.

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