Sub-base made of 2 layers of 3/4" plywood and trimmed with an additional layer for strength.  All sub-base materials were encapsulated in epoxy.

Sub-base was reinforced underneath with 3" L-brackets for support.

Template for countertop made of white butcher paper and sink template used for precise placement of stones.

Stones laid out on template for "mapping"...i.e. matching veins and stone coloration.  Blue painter's tape marked the intersection of the stones and allows for accurate re-alignment.

Stones marked with blue painter's tape for easy and accurate re-alignment.  I cannot emphasize enough how important this step was.

Stones laid on countertop for dry fit.

Dry-fitting continues...

Undermount sink in routed plywood subbase

There's a whole bunch of work here that didn't get photographed because we were both busy and covered in epoxy coated latex gloves for HOURS.  Essentially, the stones were re-laid according to the mapped out pattern on the plywood subbase using West System Epoxy tinted with graphite powder.  My husband is very familiar with this product after having lived on a wooden sailboat for years, so for us it was a natural solution.  It is not an easy DIY project, and the timing can be critical.  If you are interested in ALOT more detail, here's a document containing more information than you could ever want!

Seam after epoxy, before lots of sanding.

Seam after initial sanding.

Seam fully sanded.  Less than 1/64".

Sink stones laid out and marked, prior to cutting sink pieces. 

 Sink template will be laid on top and  cut with a router, then smoothed with sanding.

After edging was trimmed with a router.

Finished sink area

Finished "L" corner of counter

Finished room

Feel free to email me for more information if you've read the more information  located here and still have questions or require any further information.

Thanks!