(no subject)
Jun. 22nd, 2018 11:00 pmThis is the best time of the year, since it's light late.
Before vacation, I'd cast a mold around my wax-and-PLA model and let it dry over vacation. Tonight I had an hour free.
I set up the furnace with the original propane burner, because the oil burner isn't vaporizing the oil thoroughly enough so it blows liquid oil into the furnace. Bleh.
Here's the furnace burning, with the last bit of my failed 1988 Subaru Loyale engine melting. That's the inside of one of the cylinders.

This is my personal protective equipment.

I wear both a face shield and glasses because I'm nervous.
About ready to cast. I heated the mold up in the oven until it was about 250C, in the time it took to melt the chunk of engine block, another ingot, a bike hub, a bunch of old hard drive platters and spacers, and half a die-cast generator bearing housing. Furnace up top, mold below on the bricks, inside a graphite crucible because I was assuming going into this that it was going to leak and don't want molten aluminum flowing everywhere.

And casting is done: there's some aluminum around the pour hole, and a bunch more in the muffin tins I use for casting excess aluminum for the next pour.

It took almost exactly an hour from when I lit the furnace to when I turned it off.
Closeup of the mold.

The aluminum sunk WAY down. It's not supposed to do that. That means the mold cracked and it poured out the side, which is why I did it in a crucible!
Here it is, removed from the crucible, with the escaped aluminum in a nice ring around the mold base.

Oh, so close.


I had a second casting on the other side of the tree. It's an environmental housing for one of the PCB's I sell. I usually cnc mill these out of stock, but that's slow. I'd much rather cast near to shape and then just finish it in the mill. The wall thickness of this is 0.6mm, which is the thinnest my 3d printer can print. (That's twice the nozzle thickness, and it requires at least two lines.) In the future I'll do this at 1.0mm thick. The 0.6mm works fine for printed plastic enclosures, if the need is just dust or metal chips. If the need is water-tightness, it has to be metal (or plastic built by some other process I don't have.)

My hand for scale.

This is, by the way, the culmination of a project I've been working on since 1989. Furnace, burner system, burnout oven, burnout oven controller, 3d printer, printing with wax, investment allowing weird complex geometry.
Before vacation, I'd cast a mold around my wax-and-PLA model and let it dry over vacation. Tonight I had an hour free.
I set up the furnace with the original propane burner, because the oil burner isn't vaporizing the oil thoroughly enough so it blows liquid oil into the furnace. Bleh.
Here's the furnace burning, with the last bit of my failed 1988 Subaru Loyale engine melting. That's the inside of one of the cylinders.

This is my personal protective equipment.

I wear both a face shield and glasses because I'm nervous.
About ready to cast. I heated the mold up in the oven until it was about 250C, in the time it took to melt the chunk of engine block, another ingot, a bike hub, a bunch of old hard drive platters and spacers, and half a die-cast generator bearing housing. Furnace up top, mold below on the bricks, inside a graphite crucible because I was assuming going into this that it was going to leak and don't want molten aluminum flowing everywhere.

And casting is done: there's some aluminum around the pour hole, and a bunch more in the muffin tins I use for casting excess aluminum for the next pour.

It took almost exactly an hour from when I lit the furnace to when I turned it off.
Closeup of the mold.

The aluminum sunk WAY down. It's not supposed to do that. That means the mold cracked and it poured out the side, which is why I did it in a crucible!
Here it is, removed from the crucible, with the escaped aluminum in a nice ring around the mold base.

Oh, so close.


I had a second casting on the other side of the tree. It's an environmental housing for one of the PCB's I sell. I usually cnc mill these out of stock, but that's slow. I'd much rather cast near to shape and then just finish it in the mill. The wall thickness of this is 0.6mm, which is the thinnest my 3d printer can print. (That's twice the nozzle thickness, and it requires at least two lines.) In the future I'll do this at 1.0mm thick. The 0.6mm works fine for printed plastic enclosures, if the need is just dust or metal chips. If the need is water-tightness, it has to be metal (or plastic built by some other process I don't have.)

My hand for scale.

This is, by the way, the culmination of a project I've been working on since 1989. Furnace, burner system, burnout oven, burnout oven controller, 3d printer, printing with wax, investment allowing weird complex geometry.