adhesivealuminumrefrigerator
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.
Aluminum is made of aluminum - processed from rocks. This is actually a great "How It's Made" Episode. There is very little that really changes with most aluminum that you buy other than size and shape. I am sure there are slight differences in strength due to tempering processes and coating but this is usually minimal. If some aluminum is a lot "softer" than others it is probably because it is not pure aluminum.
Steel is an alloy. There are literally thousands of different steel mixtures. Depending on how they want the steel to turn out they add (or take out) different minerals - including aluminum sometimes. Steel is basically a mostly iron alloy and a lot of its properties are subject to the amount of carbon. I think if the carbon amount hits 2-3% steel becomes very rigid but also is very brittle. A ruler would not have a high carbon % in the alloy because it would need to be very flexible (relatively).
Steel for the most part is "stronger" than aluminum but it depends on the alloy composition and the tempering process (which has a stronger affect than it does on aluminum). The strongest steel is much stronger than strongest aluminum.
Typically you would need to drill a pilot hole and then thread with a thread cutting tool such as this:
however, since you are only using 2mm aluminium it should be soft enough for you to cut your own thread. Note: this will never be as clean as using the proper threading tool:
your problem is that you used a self tapping screw, I would recommend that you drill a pilot hole slightly smaller than your intended hole, then use a machine screw to create the thread (basically by tightening the screw into the pilot hole)
A bonus, is that you can also look out for Thread cutting machine screws. In this case your pilot hole must be just big enough to fit the tip of the point (as you can see it tapers at the end)
Best Answer
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:
http://www.instructables.com/id/Learn-to-Do-Aluminum-Sand-Casting/d