I have a 120mmx120mm brushless fan with an Aluminum frame, which as you can imagine, isn't very thick. I want to thread the base, so I can mount it with a fairly large screw. For that I need to add more Aluminum so the screw has more to grip on.
I'm thinking of creating a casting mold around the exterior side of the Aluminum frame (proof sealed) and then pouring molten Aluminum in it. I've seen videos of people pouring Aluminum and it seems to have a relatively low Heat Capacity compared to other metals (i.e. it will cool down and solidify before it melts the surface of Aluminum frame), as I've seen Anthill Art being made without so much as scorching the earth. Also, as Aluminum is a good Thermal Conductor, the heat would dissipate throughout the frame pretty quickly.
How would I alleviate the two problems of low Heat Capacity and being a good Thermal Conductor? I know that one always have to pour excess molten metal to the block being added to, but do you guys have better ideas??