Epoxy optical table

Hi all,

I decided to create some bigger sample made with epoxy resin. I chose some optical table. I have some 20W laser in my workshop (that is still waiting to run it), so table will be helpful to end and show laser on blog. I checked in net how they are made and what will be needed to do it.
So first was mold. I decided to made rather small table 160 x 240 mm and 30 mm high. Mold was made from plywood 10 mm thick. As was tested before release agent was silicon in spray.

Next was inserts with thread. So I have a problem here, because there is difficult to get dedicated inserts. I used my lathe to create some sample inserts. They were ok, but it take over 15 min to create one. So I would spend few hours to create inserts only for this small form. That why I decided to search something else. And I found a thing: Ericson's nut. They are used in furniture creation, but it can be easily used as inserts in epoxy casting.

As I have all parts I start to mix epoxy. Volume of this form was 960 cubic cm. I take 18% of volume resin and rest of my sand-mix. After vibrating it, form was 2/3 full.  So I have to mix more resin.
After two days I removed table from mold. There was small difficulties to do it, but I menage to do it.

I think that next time I will use some washer when I will tighten up the Ericsson's nuts. because plywood is soft and they drive in to it. I have to grind some of them, but whole table looks great.

Lucas