I am modifying some of those inexpensive 10 watt RGB floodlights available from all the Chinese sites for around $15-$20. As sold, they run on 120V and have an RF remote to choose colors. I'm eliminating all the original electronics and controlling the LED chip directly from 12 volts (via mosfets), from an Arduino acting as a DMX receiver. I'm not doing a fancy current-limiting circuit, but I do need current limiting resistors. These 10W chips draw a lot of current, so I'm using 2 watt resistors. I had initially planned to use the ceramic kind, but for price and availability reasons ended up with the big wire-wound kind. The whole floodlight is in an aluminum housing with fins. The LED chip is mounted and heatsunk at the middle of the back. The RGB cable comes in the side of the back. There is no longer a circuit board since the incoming R, G, and B wires connect to the 3 big resistors and the 3 big resistors connect to the chip. I need to hold the resistors so they don't flop around, and also it would be good if they could dissipate some of their heat to the housing. At worst, I do not want the adhesive to act as an insulator. The housing is weathertight and thus has no air circulation. (The arduino is not to be mounted in the light housing, it is external, separate, and controls several lights.) This is a budget hack. I got a good deal on the lights and don't wanna blow my savings on expensive adhesive.
(The ceramic ones would have been much easier to glue in place because they are square, but they are a minimum of 5 watts, and many times the price)