My fridge fell over and the hinge between the freezer door and refrigerator door broke. This aluminum part is crucial, so I took the gamble of repairing it with epoxy (see image). The part held for a month but the epoxy in the interface broke today. This part is subjected to shear and pulling forces so maybe epoxy is not worth a second try. How do I repair this part properly now that it is covered with epoxy.
If the original part is aluminum, that implies a home-made aluminum part would be of sufficient strength. You can use the existing part to create a sand-casting mold. The epoxy repair should hold your existing part well enough to create the casting mold, which would then be filled with molten aluminum.
One might consider that aluminum casting is not quite a home skill, but there are many instructables to cover such activity. If you have a makerspace in your area, you may also discover that a member has the necessary forge and perhaps the casting sand and mold material as well.
Here's a link at instructables.com to provide some background:
I tried to cast it like, fred_dot_u suggested. I reconstructed the part out of wax and covered it in clay. I left two openings in the clay for the molten metal. The clay dried a couple of days and I put it in the oven to preheat it and get rid of the wax. I went melting the metal in a steel can using a steel can to feed the barbecue (See figure 1A) and then poured it in the mold (figure 1B) holding the can with a pipe wrench. I spilled a lot of metal. It didn't completely fill the mold (figure 1C). There is a piece missing which I might add by using a drill and a screw (figure 1D).
But I haven't put it in use, I fixed the other part using a thin aluminum plate with drilled holes and some epoxy to create more binding surface. (no picture). I would not recommend the clay method because the mold can explode if there is some trapped air or water.