Saturday, March 1, 2014

The Foundry: Soap Dish Casting Attempt 1


I got a chance to fire the furnace up to try and cast my first soap dish with the mold.

I utilized some new tools like this steel crucible.  I made it of some pipe, the bottom was tapered by cutting out wedge shapes with a cutting torch and hammered together with help from a rosebud tip for heating.  Then it was welded all together with a piece of either 5/8" or 3/4" plate on the bottom.  With the original diameter of the pipe, it would just slide through my crucible pouring shank, so I welded some pieces of 1/2" round stock on the sides to make it compatible.

Also that is an anvil the crucible is sitting on, another treasure from the Craigslist free section.

As you can see in the background, I leaked oil, molten metal, and ash all over the place.  I have since made some oil pans to prevent this from happening, and so I don't have to worry about turning the oil up really high.  The metal leaking was from when I tried to drop some pieces of scrap into the crucible, but missed.
Steel crucible

The metal must've been giving off some serious radiation because it didn't look that pink in person.
glowing molten aluminum
In class we were taught to wait until all the red is gone before pouring, unfortunately we heeded this advise.  To my horror, when I went to pour it had already solidified!
aluminum solidified in crucible
So back into the furnace it went for another round.  I wasn't brave enough to put the lid on this time mostly because I was having a hard time working with the ball valve for the oil.  If it were barely open, it was too much, barely closed and the flame would start to go out.  This required me to constantly have my hand on the valve alternating between the two positions to maintain an adequate burn rate.  I plan on building a better burner with regulators for better oil control and blower connectivity.
The actual burning of the oil made the whole area smell like Chinese food.  The source of the vegetable oil can make a difference in aroma.
foundry furnace melting aluminum 
Skimming the slag, this time we didn't wait around nearly as long to pour it.


Unfortunately, the metal didn't fill the mold probably due to a combination of the runner being too small (a 1/2" semicircle) and the metal and mold not being hot enough.  The black stuff in the cavity is soot from an acetylene torch, I heard this would help prevent the metal from sticking.
incompletely filled die casting mold
Here is a close up of the detail on the part of the soap dish that did turn out.
die casting detail
The ingot in the sand mold was intended to resemble the metal bars from the game Runescape.
The original pattern for it was made of ceramic, I wrapped a bunch of tape around it as an effort to make a draft angle, though it still came out of the sand mold with difficulty.
runescape aluminum bar with pattern

Let's try again.

CONTINUE TO PART 5 -- Soap Dish Casting Attempt #2

BACK TO PART 3 -- New Blower and Iron Melt Attempt

BACK TO THE FOUNDRY MAIN PAGE

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