Sand casting Aluminum Key Fob

This is a quick project I made casting aluminum Key fob. I made a small flask and a pattern from MDF. After a bit of metal filing and cleaning it looked really cool. The Key Fob could be carried in the pocket and even be used in case of emergency for self defence or for emergency car window exit ;-). I also combined a bit of paracord for this project the Snake stitch guide can be found in my Paracord Projects blog.

Some late addtion threaded adge to give it more interesting look.

Sand casting aluminum handle

Last week I was walking with my family near a frozen lake, we saw a small dog running into the middle of the lake while chasing ducks then falling straight into the ice cold water in the center of the frozen lake. The dogs owner made the crazy decision to try and walk on the frozen lake to save his dog. I was thinking it would be great if I had a long rope just for emergency for cases like this in my car. Anyway the dog was saved by his owner and I made a decision to place some rope in my car with a strong aluminum handle.
I started by making pattern for my sand casting using 20mm MDF. First I drew the shape of the handle making a few corrections along the way. After the drawing was done I used my drill with a core bit and jig saw to cut the handle shape. I used a wood chisel to shape and round the grabbing part for the fingers. Last I gave it a good sanding and used acrylic paint over it.
After I opened the flask and the mould was ready I removed the pattern and cut it into 4 parts clamping it back to create the inner handle core parts. The reason I cut it is to get good quality sand casting. It is impossible to press the sand out of the pattern without breaking it if the pattern is in one part.
I released the clamps and carefully took the pattern out. Now I have the two inner core parts. I placed them in the correct place in the flask and after close the flask tight with large clamps.

In this casting I tried something new using two tin cans as a sprue and riser extensions. The cans are filled with petrobond and the cavity I made is bigger then the flasks sprue and riser. I was looked after pouring the molten metal and it worked very well. I could see the riser feeding the molten aluminum into the mould, really cool. See picture below of the riser extension.

I cut the sprue and riser with my hack saw and used a metal file to chip off the extra aluminum, then I drilled a hole for the rope and used an electric sander with different sand paper grades. After the sanding part I used fine metal wool for the final polish. To get an even better polish results it could be done with aluminum polishing products and a buffing wheel.
The rope fits very well into the handle hole and the handle is very comfortable for grabbing. The handle is heavy enough to be used as a weight in case it has to be thrown.

Foundry gas burner

After using charcoals for some time I started powering my furnace with propane gas. I started by constructing 2 burners and after a few uses I have to say its great regarding cleanliness and aluminum melting results. In this image I melted a bar of aluminum in just a few minutes and finished with many more ingots.

The down side of using propane is that it's more expensive then charcoals or waste oil.
The first propane burner I made following Ben Baker's design so many thanks to him for all his help and great sketchup design.
The first burner is constructed from a stainless steel pipe nipple 1/2"x8", bell reducer 1/2"x3/4", mig welding tip 0.6-0.023, mig welding adaptor-m6-mb36, square steel stock 3/8"x3/8" and washer 3/4" (air choke plate).
The second burner is constructed from a stainless steel pipe nipple 3/4"x6", T-joint 3/4", copper head plug 3/4", mig welding tip 0.6-0.023, mig welding adaptor-m6-mb36 and a washer 3/4" (air choke).

To create the adjustable choke I drilled a hole in the (3/4") side of the bell reducer and top of the 3/4" T-joint. Making the threaded hole with a tap and die bit.
I used a 6mm bit to drill the copper plug fitting in the mig tip adaptor.

I tried to take some images of the propane burner in action changing the ratio mix of the air and gas but in the images the only flame that could be seen is oxidizing blue flame. Oxidizing blue flame can destroy metal pipe crucibles very quickly leaving a nice hole and a pool of molten aluminum in the bottom of the foundry.

I haven't used an air blower combined with the propane burner before so I will try that in the future and post my experiment results. Once my foundry got to the right temperature I started pouring one crucible after the other for about 3 hours. The refractory insulation keeping all the heat inside the furnace is very important so it pays to make a good refractory.
Here is a video of my foundry in action using the propane burner before I installed the adjustable choke washer.................Next step a waste oil burner :-)

This is another addition to my furnace, I used a screw to secure the burner into the correct location and angle.

Sand casting, aluminum Tap and Die handle

A few days ago I was using my Tap and Die set, While making a simple threaded hole I used too much force on the handle and the aluminum part snapped broken. I decided to duplicate the part that broke using sand casting method. First I glued the two broken parts with super glue and after that it was easier to make the sand mould. It took me twice to make this tiny mould, to my opinion it's easier to create a mould of a bigger size object rather then working on a macro level making a small part. I also made a divider in a bigger flask to save time on ramming the petrobond. The casting result was very good just needed a bit of cleaning with metal file.
To create the holes and threaded holes on both sides I used my bench drill.