Pricer-I cannot see the pictures you have posted. You may need to use Photobucket. It is a free hosting site. Here is a filler that will do the job for you when casting parts-
http://www.jamestowndistributors.com...34&nobot_crawl
I don't know where you are located but there are a lot of west systems dealers around the country. I would also suggest using the west systems epoxy. It is good stuff. The more filler you use the stronger the part will be but it needs to be thin enough to pour freely into the molds. You may have to experiment to get the correct resin to filler ratio.