DIY LED thermal epoxy replacement

[BradB]

I've ran DIY LEDs for around 15 years. LEDs are directly attached to two 24"x48" aluminum sheets that are both the lid of my canopy and function as heat syncs. This almost worked without any additional cooling, but I did add a fan for longevity. Every few years, I remove any dead/dying LEDs and add new ones. I attach LEDs using arctic silver alumina premium ceramic, which was less than $5 when I started. Now it is $25. If I do both panels separately once a year, that was < $10/year and now is $50/year.

I don't know if DIY LEDs still make sense in 2026, but if I continue to use them, I need a cheaper physical attachment and thermal solution. What is everyone using?

I had a scare this morning - half my LEDs didn't turn on, and I suspected my HLG-480H-54 ($180) but it turned out to just be a 20-year old timer that finally failed. But this got me thinking about either going to premade fixtures or getting around to replacing dead/dying LEDs.

 

[Gumbies R Us]

@Troylee

 

[Troylee]

Really not sure what people are using today. Maybe @oreo54 can help ya.. I haven’t done diy led’s in 15 years or so.

 

[oreo54]

I've ran DIY LEDs for around 15 years. LEDs are directly attached to two 24"x48" aluminum sheets that are both the lid of my canopy and function as heat syncs. This almost worked without any additional cooling, but I did add a fan for longevity. Every few years, I remove any dead/dying LEDs and add new ones. I attach LEDs using arctic silver alumina premium ceramic, which was less than $5 when I started. Now it is $25. If I do both panels separately once a year, that was < $10/year and now is $50/year.

I don't know if DIY LEDs still make sense in 2026, but if I continue to use them, I need a cheaper physical attachment and thermal solution. What is everyone using?

I had a scare this morning - half my LEDs didn't turn on, and I suspected my HLG-480H-54 ($180) but it turned out to just be a 20-year old timer that finally failed. But this got me thinking about either going to premade fixtures or getting around to replacing dead/dying LEDs.

Yea just switch to the cheap thermal conductive silicone "glues"
If one digs into the specs you will find there isn't much difference "if" I remember correctly.

If you can find the Tianmu stuff it is dirt cheap and adequate heat transfer.
Dries really slow though. Careful though Tian mu makes numerous products and it isn't always easy to pick the right one. Well it's the ads that make it confusing.

Heat Conductivity Coefficient（Grey/white) :λ≥1.5Wm.K​

https://www.aliexpress.us/item/3256805126821103.html?gatewayAdapt=glo2usa4itemAdapt

I do not believe "white" is useable. As I said it can be difficult trusting what they say.
No "numbered" silicones are heat transfer types AFAICT.


Actually if you hunt down some thermal pad sheets many actually have a wee bit better transfer characteristics.

There are "superior" products with "superior" products but not always actually superior.
Back to adequate.
"Heatsink Plaster " is the easiest to find.
Thermal Conductivity: >0.671W/m-K
https://www.aliexpress.us/item/3256810442067174.html?spm=a2g0o.detail.pcDetailBottomMoreOtherSeller.1.4e1bQH5oQH5oX7&gps-id=pcDetailBottomMoreOtherSeller&scm=1007.40050.354490.0&scm_id=1007.40050.354490.0&scm-url=1007.40050.354490.0&pvid=2a414323-ccd6-4371-a6f4-04b4be09e32d&_t=gps-id:pcDetailBottomMoreOtherSeller,scm-url:1007.40050.354490.0,pvid:2a414323-ccd6-4371-a6f4-04b4be09e32d,tpp_buckets:668#2846#8107#1934&isseo=y&pdp_ext_f={"order":"11","eval":"1","sceneId":"30050","fromPage":"recommend"}&pdp_npi=6@dis!USD!5.58!1.09!!!37.18!7.26!@2101e56817921738111115841e1057!12000053019910420!rec!US!!ABX!1!0!n_tag:-29910;d:957891be;m03_new_user:-29895;pisId:5000000218165380&utparam-url=scene:pcDetailBottomMoreOtherSeller|query_from:|x_object_id:1005010628381926|_p_origin_prod:

Last is JB Weld which has some products that are use-able as thermal transfer adhesives.
I'm not versed in which are and which are not.

 

[oreo54]

An example of a double sided tape thermal pad material
https://www.digikey.com/en/products...gmCx99DeFN6k6XDYRXbpMWpFE8RerY78aAktuEALw_wcB
https://wakefieldthermal.com/content/data_sheets/Double_Sided_Tape_WakefieldThermal.pdf
10x10 inches..
Or
https://www.ledsupply.com/accessori...pVBGz1MAeDN_3Dw_LG37PX6vSSWHv_40aAhSGEALw_wcB
$2 for 10 stars(?)

Side note.. The issue with Arctic silver..
https://www.techpowerup.com/forums/threads/us-department-of-energy-debunks-arctic-silver-5.257451/
Name brand..
https://www.dow.com/en-us/pdp.dowsi....04028948z.html?productCatalogFlag=1#overview
Thermal conductivity: 2.8 W/mK

 

[firechild]

I don't know if DIY LEDs still make sense in 2026

I still believe they do. A Radion XR30 is around AU$1800, I'd need 2 (at least) for my aquarium. For way less than $3600 I can build a pretty good DIY unit that ticks all the boxes for modern units, with automations and remote connectivity. The DIY space has improved immensely in the last 15 years (I recall the early Arduino controllers that required a pretty decent level of technical expertise) and is way more accessible to people who can't write a single line of code. I've build DIY units for 3 different aquariums since 2020.

 

[fish_collector]

An amazon search comes up with several thermal epoxy paste options for less than $10. As long as the diodes remain affordable, you already have the know-how so why spend the big bucks on lights when you've been building your own for this long? You can buy a lot of diodes and paste for what it would take to hang a set of new LEDs over your tank.

 

[BradB]

An amazon search comes up with several thermal epoxy paste options for less than $10. As long as the diodes remain affordable, you already have the know-how so why spend the big bucks on lights when you've been building your own for this long? You can buy a lot of diodes and paste for what it would take to hang a set of new LEDs over your tank.

I have not seen any thermal epoxy options on Amazon below $25. Maybe I just didn't try the correct search, but let's not confuse different things.

thermal = conducts heat
adhesive = sticks 2 things together
epoxy = 2 part adhesive using resin and hardener

Now, I am not saying I need a thermal epoxy, just that is what I've been using for more than a decade. If you are recommending a thermal adhesive that is not epoxy, or thermal paste that isn't adhesive, it might be a good choice. But please be specific.

Picking the right product is important because if it doesn't work right, not only did I waste hours, but my corals and clam are going a few days without light and/or I am adding copper, tin and other bad things into my water.

 

[fish_collector]

I did an Amazon search and the very first thing that came up is thermal glue, and it says it can be used for LEDs, heat sinks, chipsets etc. You said you were looking for other options, so here is another option. The reviews do say it takes a while to set up. Unfortunately you will have to be the one that tests it to see if it does what you need it to do.

https://www.amazon.com/clp/B072MSXHJD

So you have an aluminum sheet as a heat sink with the diodes epoxied to it correct? The link to the thermal glue I gave you might work for what you need. I'm not sure how many you are reattaching, but from experience with my own diode attaching projects it doesn't take much at all.

And yes, I'm educated on what the definitions of thermal, epoxy and adhesive are, and I'm aware you need to attach them to the heat sink "permanently" without them falling off, while at the same time transferring heat away from the diode. There's a few options for attaching diodes to a heat sink, it looks like there's even thermal adhesive tape that's available but I know nothing about that. I used thermal paste with my diodes on the heat sink, the soldered electrical connections hold them in place though so the paste is just to transfer the heat away.

Good luck finding what you need and post some pics.