Well, I certainly feel like I've failed given that nothing I've tried has been remotely close.... I'm ready to admit I've got a lot to learn about casting. So now it's time to step back and do some research.
I decided to throw a couple of my Amazon bucks towards some books I'd been eyeing.
The first book is The Complete Handbook of Sand Casting by C. W. Ammen. This book is a wealth of information by a gentleman who has obviously been working in a foundry most of his life. I'm not sure if Mr. Ammen is still alive (the book was published in 1979) but I imagine he would be a very interesting man to have a conversation with.
My only complaint about the book is that it contains drawings rather than actual pictures. Though in some cases, I suppose the drawings are better at demonstrating a concept and showing contrast. Like the one on the upper left of the cover, for instance.
It contains a lot of information and may go a little deeper than most people might want, but it is a solid reference.
The second book I picked up is
How to Cast Small Metal and Rubber Parts by William A. Cannon. This book is a little easier reading though I'm only partway through. The author's experience in casting is from antique auto restoration and most of the discussion and examples relate to that which is just fine by me as I find that very interesting in and of itself. I haven't gotten to the section covering rubber but am looking forward to it.
When I get done with the book, if my opinion changes very much (positive or negative), I'll be sure to make a follow up post.
Hopefully after a little more studying, I'll finally get casting figured out and get back to melting metal. I've already learned quite a new things from these books and am feeling optimistic.