Steel stuck in aluminium

[Lykle]

Well, I managed to really screw up here.
I was casting a nice golf ball. It was going to be a handle for a tee and golf ball tool that will allow my father to stick the tee and the ball into the ground without bending his knees. Even had a depth setting with automatic opener.

The golf ball is going to be mounted on a carbon fiber rod of 21 mm diameter.
So I thought I would cast the ball with a core, but I had forgotten the correct way to make a core (something with white sand and molasses?) I had a piece of steel, nice and smooth and exactly 21 mm diameter. So I used that as a core, fully expecting it to be easy to remove.

Yep, you guessed it, no way in h*ll am I able to get it out. So I heated it up, no help. Froze it all and heated up the aluminium quickly, no help.
Now I drilled a hole throughout the steel, tapped it and filled the cavity with vaseline. I am freezing it again and then I will try to screw it out. You know the trick, force grease into a blind hole. But I have little hope.

I probably will have to cast a new ball, make it solid and bore it out. But my fathers birthday is in 2 days! Getting close.

 

[bret4]

Mill or drill it out as close to the size of the hole. A thin wall steel tube may be easier to remove. If not you may have to mill or drill it just a little bigger to cut ti out of the ball. Then fit the larger hole to what you need it to fit. If you go bigger maybe you can press fit a bit of tubing in the hole to make it the right size. A bit of brass may tubing may look nice like that is the way you were going to make it.

 

[rhitee93]

Can you tap the hole you drilled for a zerk fitting and use a grease gun to pump grease in and force it off hydraulically? I've seen this done to remove steel dowel pins from aluminum fixtures...

 

[Lykle]

I tried a couple of things, but nothing really did the trick.

So I hung it on my bad trophy wall and cast another ball. Was a lot faster than trying to fix this one. and the casting actually came out better too.

Gave it to my father yesterday and he was most impressed.

Thanks for the tips guys, they have been filed in the "Oh I have to remember that one!" file.

Lykle