Well been reading again about casting so I made a melting furnace at the end of feb. 2008
To melt aluminum down and pore in too bigger blocks and stuff.
Got most of the info from here http://backyardmetalcasting.com
Will post new pics on this at a later time
Speedchaser

What are you using for the furnace?

Any updates?

UPDATE new pic's

NEXT

I will be interested to see how the billet machines, you may find it will be pourous.

Hello I'm using 6061 so its not really porous at all I will brake one in press today and take a pic. so we can see
The big problem I will have is the hardness of the 6061 it will never be as hard as the original the most that I can do to it is a T4 hardness witch is gust after it goes to a solid
You quench it in 70 to 80 deg. Water than let it shelf harden. The melting of 6061 is gust a test for the learning on how every thing works. Soon will make a mold for some thing
And try that out guts to see how it pores.
Thanks For looking
SpeedChaser

Wow I thought it would be more porous
then what it was and a lot more brittle
It took a lot to snap a chunk off in press

The porosity is probably caused by the shape. The mold dose not have a riser to feed the center of mass as it cools. The slug starts to cool around the edges, as the center cools and shrinks it pulls away from the already solidified mass at the edges. Mold design is an art form all by itself. Read up on it and play with it some, it’s kind of fun if you don’t have production deadlines.

that's not a bad result for your first attempt

Working in a foundry, I can say a little here. I can operate a 500kw furnace, make molds, create cores, etc. The last part that cools is the heaviest mass. It must be fed by a riser, channeled through a runner, through your gating, and into the part cavity. Your gating is essential. It controls the flow of molten metal into the part cavity for quality and finish. Molds are made in various ways. If your gating is too large, you will pour too fast, and it will not filter out any impurities in the metal. If it's too small, you'll pour too slow causing cold shot (cracks or defects in the part causing premature failure). Typical pour times are between 7 to 12 seconds depending on part. Your riser must be be attached parallel to part and gating, and fed vertically from a point higher than the highest point higher than the top of the part itself. Read up on mold designs. Furnaces can be bought online for household use. I've thought about casting various parts for the oddy junkies myself. Any questions on this, pm me. I work with the people who would have all the right answers.