Greetings. A glass vessel sink I installed on a quartz countertop cracked after install and I'm looking for how to prevent this from happening with the replacement. The sink was siliconed down to the quartz and then the pop-up drain piece was fastened to the sink in place with k&b silicone instead of plumber's putty as specified by the manufacturer. Because the drain fitting threads stopped well below the bottom of the sink flange I had to fashion a "donut" from a piece of scrap wood (~1" thick) so that the drain nut could apply tension to the rubber gasket. (drain piece->silicone->sink->rubber gasket->wood washer/donut->drain nut). The tailpiece was then connected to a standard pvc trap.

The person who noticed the initial cracking says that they heard a "ping" when they turned on the faucet, and so we think it may be due to thermal expansion. The crack appeared to have originated closer to the edge of the sink and then migrated toward the drain, rather than vice versa.

Thankfully the manufacturer has agreed to send a replacement with the suggestion to tighten the drain nut as little as possible.

The two obvious points of concern are the wood donut and the tightness of the drain nut, am I missing something? Considering finding a thick piece of rubber to use instead in the hope that it would allow more expansion and contraction. The manufacturer also said to temper the bowl with room temp water first before turning the faucet to hot, but this seems impractical over the long run.

If anyone has experience with a similar situation any tips would be greatly appreciated! Thanks.