Thank you for the help jpanhalt. I live in Maryland, US but currently I am in Indonesia and I will be in Thailand next week. The competition is 5 months away, so I have some time. I was thinking of going to an iron art shop to get the core.
I want to try putting in some switches to do one electromagnet for maximum lifiting and parellel electromagnets for fast moving. I have a feeling you will still be right, but I have a few months, so I want to try a few prototypes.
I am way out of my leauge on calculating the size of the core as to avoid saturation. I found a good website for this but the concepts are too advanced for me. I will try to post it when I get back to my computer.
When I start building I will make a new thread with pictures, test results, and a summary of what has been discussed so far.
Some questions:
My concern is that a switch might add too much resistance. Do you think 5 switches would add an appreciable ammount? Is there a certain style of switch that is better?
Is there a type of solder that would be good for this application? Low resistance and able to withstand the heat.
I have some old PC heatsinks. Would It be helpfull to dremel them up and use thermaly conductive epoxy to secure them to the upper side of the electromagnet? Or would the wire still fuse at the same current because the lower side would have no help.