The time spent laying out where everything will go on your ice chest air conditioner is critical, as you can’t undo a hole once it’s cut in the lid of your new $80 cooler. The old adage “measure twice, cut once” really applies here, as there’s nothing worse than cutting a hole for a blower, only to turn the lid over and realize that there isn’t room to center a radiator underneath it.
I’ve taken to cutting out pieces of cardboard the size of blowers, radiators, motor controllers, and whatever else is going to be mounted on the cooler lid so I can place them on both sides of the lid to see how it’s all going to fit. Once done, I then outline the item in pencil. After measuring to make sure everything’s symmetrical, I then carefully cut on the inside of the lines (enlarging a hole is easy, reducing one is pretty much impossible).
Whether one surface mounts heat exchangers or countersinks them into the cooler lid depends on the lid characteristics – especially thickness. The build I’m currently working on required countersinking nearly everything to do it right, so I’ve had to make a ton of holes in this lid – the majority of which I did with a razor knife and straightedge (tedious beyond belief).
In my opinion, this is the worst part of building a Frankencooler. From here, it’s a matter of mounting all the components in their places and doing the respective electrical and plumbing connections – something I find a lot less nerve-wracking.