Three Oslons tested: 1) latest gen. Oslon Black Flat 2) SSL80 4000K 92CRI latest gen. 3) SSL80 4500K 96CRI 1 gen. before latest

Not sure if it’s a good idea:

That post is a question, maybe I’m missing something. But maybe Q8 reflector is not good for throw.

Sofrin Q8 with XP-L HI is noticably throwier than the BLF Q8. I would expect the Black Flat to produce results of a similar nature.

If the XP-L Hi in the Sofirn Q8 throws 106kcd, as I measured, a Black Flat should throw about 160 kcd, at ~2500 lumen OTF.

If the grounded thermal pad is the only drawback, that can be dealt with. I have Arctic Alumina Thermal Adhesive to make a “mask” between the emitter shelf and MCPCB, I can make polycarbonate screws if need be to ensure the MCPCB doesn’t ground through the mounts. Or I can get ceramic screws. Or nylon ones, whatever. Don’t even need the screws if the MCPCB is glued down in the first place…

djozz? Only 600 lumens per Black Flat? Conservative isn’t it? Reckon I’ll find out, should have the emitters here by end of week and the Sofirn Q8 is en-route… as are new boards from Neven. Of course, the original MCPCB should work fine here…

If during curing of the thermal glue you connect led+ on the ledboard and the Q8 housing to a small power source (I use a led-tester for that), the Black Flats will light up if you have a short between ledboard and housing, so you still have time to correct before the glue is hardened.

The only danger even if the thermal pad grounds out is not having modes, same as shorting the negative lead, so it’s not really that big a deal overall anyway. Thanks though, I know to take precaution so it should work out all right. Thinking about using a similar light and putting 9 of em in. :smiley:

I like the Arctic Alumina Thermal Adhesive because it can be removed through application of heat. :wink:

Is the center pad just connected to ground? seems like there was too it then that, although I have not looked into it that close.

The negative pad and thermal pad are connected.

What are your thoughts on this? http://www.thermal-grizzly.com/en/products/13-minus-pad-8-en
I already posted this in another thread. I bought a 0.5mm sheet of this and will be testing it in a Tool AA with an Oslon. You think it’s too thick for good thermal contact? I think with a screwed down MCPCB it should become very thin, as it’s very elastic. At least it has the same thermal conductivity as Arctic Silver 5.

I would not want to use that under the mcpcb, it has horrible thermal properties compared to thermal paste.

You think the layer stays too thick? Because Artic Silver 5 is 9,0 W/mK and this is 8 W/mK. Don’t mix this up with the crap they put under cheapo heatsinks. Just by the description, this is some next level thermal pad. :smiley: :+1:

Edit: They go up to >30 W/mK but really cost an arm and a leg.
Edit2: http://forum.notebookreview.com/threads/thermal-paste-roundup-performance-price-recommendations-update-thermal-pads.796820/ OK maybe they still suck. :frowning:

I have seen the new carbon nanotube thermal pads that are promising, is that what this is? In the picture it looks like the normal silicone based thermal pad.

In which case you are correct, they are almost always way too thick. It says the thinnest version is 0.5mm thick for example. Most thermal paste would be a fraction of that.

Graphene thermal pads are conductive.
Those only work well when surfaces are very flat and parallel, they perform similarly to thermal paste.
These pads are not that, it is some different custom materials, much better than just regular silicon thermal pads.
They are also pretty expensive, more W/mk = more cost.

If you need to apply a layer of thermal adhesive that is insulating you need to use some sort of spacer like a piece of electrical tape on an edge in order to keep the two surfaces apart while the epoxy dries.
A piece of electrical tape will be like .2mm or so.
Using these high performance thermal pads will still be decent for a low wattage LED like the black flat, especially since the pad compresses, only problem is that you still need to secure the PCB down somehow without using screws that will create a conductive path.

Anodized screws maybe? May get problematic when the anodizing wears off.
I just realized there are even screws completely made from plastic, well…

Yeah, or ceramic screws which are super expensive.
Another way is to use some sort of hold-down plate with screws outside the MCPCB area.

The easiest way is to use thermal epoxy and just remove the screws once it is dry.

Small insulating fiber washers + insulated sleeves work for other applications. There is no reason they shouldn’t work to insulate screws from an MCPCB.

How do you keep the threaded shaft of the screw from contacting the MCPCB inside the hole? The walls of the screw hole? Easiest to use a non-conductive screw. Or none at all.

“+ insulated sleeves”

Better if insulated washer and sleeve are one unit, but probably hard to find.

…or get some Laird thermal sheet stuff.
Various thicknesses available.