We cast a homemade gear wheel from aluminum instead of plastic

This workshop will teach you how to make copies of simple aluminum parts. In our case, the drive gear for sliding gates has broken. In the factory version it is made of plastic. We will do it.

We will need:

  • Seconds glue.

  • Plasticine.

  • Gelatin.

  • Glycerol.

  • Wax.

  • Gypsum.

  • Self-adhesive sealant.

  • Aluminum (in the form of any unnecessary scrap).

Everything you need is bought at hardware, grocery and hardware stores. It is not expensive and is always available. Of tools and other things, various metal containers or pans, a gas stove and a hearth are needed.

Manufacturing process

Let's get down to the process itself. We take the parts of the chopped gears and glue them with second glue.

We fill all the technical cavities in it with plasticine to make it easier to cast the part.

Then pour the gelatin into the pan and dilute it with glycerin. Melt in a water bath until smooth. When the gelatin is ready, place the part in a small container and fill it with the resulting mass.

We give some time to freeze. Next, make small incisions to remove the gear. The first form is ready.

Now you need to melt the wax and cast the part from it.

When the part is ready, be sure to compare its size with the original one.

We got a little less than it should be. The issue was resolved by window seal. You need to stick it on the gear teeth and cut off the excess.

Then repeat the previous steps. We melt the gelatin shape and again fill the part, remove it and fill the wax. Now it turned out exactly in size.

The next step is to breed gypsum in a metal container and fill it with a piece of wax. Let the gypsum harden and calcine the container in the furnace to remove wax from it.

We tried to melt wax from gypsum in the oven, but it did not work out to the end, which had a bad effect on the quality of the final part.

When the plaster mold is ready, we melt the aluminum in the furnace.

Pour molten metal into gypsum, cool in water and get the finished part.

In general, it looks good, but requires minor modifications.

A file and a hacksaw for metal are enough for this.

A lathe will facilitate processing, but its presence is not necessary.

All that remains to be done after processing the part is to put the gear in its place.

Do not forget to lubricate the moving and rubbing parts of the mechanism. So they will last much longer.

An important point! When pouring metal into a plaster mold, be extremely careful. If the gypsum is not completely dry, then with strong heating from the cast metal, the water will quickly evaporate. This will lead to the fact that the form begins to “spit” with steam and small droplets of hot metal.


Today, plastic parts are often used in highly loaded mechanisms. This is a tricky marketing move that forces us to fork out for expensive parts. The new aluminum gear wheel is easy to manufacture, will last much longer and significantly save your budget.