So, I’m currently working on modding a flashlight. The old LED was glued down (with something that looks sort of like hotglue???) and removed. However, it left a bunch of residue that needs cleaned before the installation of the XM-L2s that will be installed. However, there is still anodizing underneath the glue. Does the anodizing have any negative effects on the heatsinking of the LED?
How would you guys go about prepping this LED mounting surface?
Anodizing isn’t as good as bare metal, but I think most people would agree that it’s plenty good enough. Use isopropyl to clean any residue, then use a good thermal paste (I use Arctic Ceramique II) under your new LED. (not too much, just enough for coverage)
Right. Approximately how much difference does it make between bare metal and anodized?
Also, is it ever acceptable to use thermal compound instead of a thermal paste? The particular design of this flashlight pretty much sandwiches the LED to the contact surface when you assemble it.
I usually use terms thermal compound/paste interchangeable (probably incorrectly)
any reputable, thin TIM should be fine.
I can’t quantify the difference between ano and bare metal, but on the the few lights I have had an anodized shelf I don’t think twice even with very hot builds. The only thing that would cause me pause is if it was a dirty, thick, uneven ano job. You want the surface to be level. If you think you can get in there and sand the ano off without losing a level surface, go for it.
edit: I know my answers are kind of vague and subjective to my experience, maybe somebody else can chime in with some concrete numbers.
Before modding a light you have to read it it’s rights, and have it sign a liability waiver. This is important before any critical operation that could result in an untoward outcome.
Oh, is this really incorrect? At least I think thermal adhesive is the most correct term if the thermal filler stuff also acts as a glue.
Ensuring a good thermal contact is something that's not discussed enough IMO. Tightening the reflector to star to maintain star to pill contact is common, but I feel that's somehow wrong. Unless the emitter board is soldered in or held by screws, it might move and lose its intended thermal connection. Other kinds of damage could occur as well depending on insulators or spacers used.