Trying to make some coasters.

Random question but I can’t find anything that will seem to work for this craft/project.
I saw some bottle cap coasters that my buddy bought at an art show were metal and filled with resin and bottle caps. I figured it would be easy to replicate but I can’t seem to find a metal coaster that has a lip on it.
A suggestion I found online to use tuna cans and easy release resin and pop them out after they dry.

I don’t have a picture with the metal but here is an idea of how it looks without.

http://www.alternativeconsumer.com/wp-content/uploads/2011/RD_2011/march_april/beercapcoaster.jpg

I also did a search and found Josh’s thread which involves metal powder coated flanges which is a little more work/resources than I am looking to use.

Can you get crafty with a piece of thin sheet copper and some hand tools? I’m thinking maybe use a pliers to pinch up the edges of the copper, creating a wall high enough that you could pour the resin in. Copper is very easy to modify, however it does have a breaking point so you’ll have to play around with it a bit to understand these limits.

Perhaps make a fiberglass mold?

I was going to suggest getting strips of aluminum that you could put a “brush” look on.

Ive done this many times with beer caps without the metal. What you need is a mold. Cant remember the site I ordered from in California but you need this. Also dont forget the mold release !

What you need: http://www.amazon.com/Environmental-Technology-3-Inch-16-Inch-Castin/dp/B002CQM8XW

Instructions: http://www.marthastewart.com/268788/resin-casted-clover-coasters

Check out this homemade 'coaster:

That answers everything

Where can you get the molds locally?

I am thinking about trying the tuna can method. Since resin is cheap and beer caps are free.
Now I just need to find someone who eats tuna or canned chicken.