Epoxy Granite In Practice (Mineral Casting, Polymer Concrete)
This thread is meant to provide a practicum for the application of Epoxy Granite (Mineral Casting, Polymer Concrete).
From test samples to filled bases to large scale machines to precision gantrys to metrology tables and more, all photos, videos, links and comments are welcome.
Please assign appropriate copyright notices where necessary.
To learn more about the theorectical use and application of Epoxy Granite, I highly recommend reading the thread entitled "Epoxy-Granite machine bases."
Once you have increased your understanding and are ready to give it a try, please feel free to share your work here.
~John
Thank You For Getting Us Here.
The first post in this thread should rightfully pay homage to walter, lgalla, ckelloug, greybeard, jhudler, brunog, martinW, Geof, and the many others who continue to make the original Epoxy-Granite thread so interesting.
Thank You.
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Alumina Oxide Sample #1 -- Exposed
Happy St. Patrick's Day !
Got a chance to stop by my friend's granite place. I was interested in seeing what was below the surface of AlOx sample 1 (the hockey puck).
First we hit the top with a belt sander. This stuff is hard. Harder than working with Mohs 7 granite that's for sure. It took time.
Then we polished it using a water polisher at grit 800 / 1200 / 3000.
Overall, the compaction is good. We know the surface resolution is okay. Lack of good vibration still yields microscopic bug holes. But it's close.
1. Top view, sanded and polished. The white discoloration is actually where it needed to be sanded further. I stopped because the belt was beginning to burn and smell.
2. Up close. You can see the bug holes. The aggregate seems evenly dispersed which is good. Note the sparkle. Part of the mix.
This piece is 10% epoxy by weight. I tried another at 7-8% but it's too difficult to work with without vibration. I don't recommend it. I'm staying with 10%. Seems to work best.
~John
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Practice With Larger Pieces, Casting Inserts
Still having problems with air but that will work itself out with a vibration table of some kind.
Used a heavy baking pan ($12.99): 310mm x 220mm x 25mm.
1, 2: Inside the pan. Inserts are attached using double-backed adhesive pads.
3, 4: Close-up showing a plastic flange mounted to a pad.
5. Type of pads used.
6. Used rice to determine approximate volume. Got this idea from Fu-tung Cheng. His youtube videos on casting concrete are very good and worth a look.
7, 8: Actually takes 2 of these (8 cups) to fill the pan.
9. 8 cups of material weighs 4100g. Epoxy is then 11% by weight.
10. Worked well. I thought it would be difficult to de-mold this piece but it popped right out. The pan's anti-stick surface is better than mold release -- which I forgot to add.
11, 12: Pealed back the adhesive pad. Not a clean hole (my fault) but proof of concept. Casting inserts is no problem.
13. Close-up of an insert. Absolutely smooth to the touch. No transition at all between material and pad.
14. Surface is nice and flat. The pan makes a good mold.
15. Indentations of the letters are 1mm wide.
~John