Originally Posted by doyll
You don't use silicone for this sort of thing. You want a rigid plastic that is not brittle. Acrylic will work but it is pretty easy to crack / break. I would use something like ABS plastic or polycarbonate. ABS would be cheapest. Find a plastic shop near where you live and stop in. Explain what you want to do and they may give you some scrap pieces to make your adapters with. If not they won't charge you much.
As for cutting of the edges, I assume you mean on your PH-F140HP fan? No, they are 140x140mm. Adapter base may need to be trimmed depending on the spacing of case / cooler holes, but most allow for fans being 141mm square.
This makes sense (I'm 100% noob with modding), I will probably get a piece large enough so I can fit it directly to the radiator after attaching all 3 fans to it. That way there are even less air gaps vs 3 separate pieces.
"Plastic shop"... so would Home Depot or Lowes sell what you're talking about? Is there any way to get some online? I live in the middle of nowhere so I shop online mostly.