Cogsy
Well-Known Member
With still no word on the new castings, but a desire to keep machining something, I decided to have a go at casting my own heads.
I cut up an old alloy intake manifold from a Ford 6 cylinder engine and threw in some bits and pieces I had around the place as well. Once it was melted I also added around 4% copper to the melt, based on some experiments bmac2 did recently, to improve the machinability.
I measured the castings I have and there was plenty of meat in them to use them as patterns directly so that's what I did. Here's the result straight out of the sand.

Here's a shot of them with an original casting for comparison. You can see my surface finish is nowhere near as good.

I figured I could fix the finish problem later, so I attempted to machine them. They cut very nicely, not gummy at all, but they were full of tiny little gas holes and were unusable. I was annoyed so I didn't get any photos of the porosity.
So I have decided to abandon my casting attempts as everything I cast lately has been porous (I think I might be making the melt too hot), plus my surface finish isn't up to scratch. Instead, I grabbed a couple of scrap Ali bars from my stockpile and I will attempt to machine the heads from solid. I don't have a bar big enough to make the two heads together so I'll have to make them one at a time and hope they come out the same.
Here's the first piece of scrap straight out of the pile.

And here it is all squared up and ready to go.

Next update we should know if this plan is going to work.
I cut up an old alloy intake manifold from a Ford 6 cylinder engine and threw in some bits and pieces I had around the place as well. Once it was melted I also added around 4% copper to the melt, based on some experiments bmac2 did recently, to improve the machinability.
I measured the castings I have and there was plenty of meat in them to use them as patterns directly so that's what I did. Here's the result straight out of the sand.

Here's a shot of them with an original casting for comparison. You can see my surface finish is nowhere near as good.

I figured I could fix the finish problem later, so I attempted to machine them. They cut very nicely, not gummy at all, but they were full of tiny little gas holes and were unusable. I was annoyed so I didn't get any photos of the porosity.
So I have decided to abandon my casting attempts as everything I cast lately has been porous (I think I might be making the melt too hot), plus my surface finish isn't up to scratch. Instead, I grabbed a couple of scrap Ali bars from my stockpile and I will attempt to machine the heads from solid. I don't have a bar big enough to make the two heads together so I'll have to make them one at a time and hope they come out the same.
Here's the first piece of scrap straight out of the pile.

And here it is all squared up and ready to go.

Next update we should know if this plan is going to work.
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