Which UltraClear epoxy should I use for the thickness I want to pour?

Go by how thick the epoxy layer itself will be, not how thick the piece is. A 1.5"-thick wood sign that only needs a clear coat is a coating job; a 1.5"-deep pour into a form is a casting job.

Coating a surface (1/8" per coat): UltraClear Bar & Table Top Epoxy. It self-levels to 1/8" and is our strongest, most scratch-resistant epoxy, so it's the choice for bar tops, table tops, countertops, live-edge slabs, and any surface that gets used. For more depth, pour another 1/8" layer every 4 to 6 hours (up to 10 hours without sanding), to 1.5" total.

Pours 1/8" to 1/4" thick: UltraClear Art & Craft Epoxy. It pours in 1/8" or 1/4" layers, with more layers added after 4 to 6 hours, and its 30 to 40 minute working time suits coasters, jewelry, trays, and resin art.

Pours thicker than 1/4": UltraClear Deep Pour Epoxy. Use it for deep voids, molds, casting, and encapsulating objects. It pours 1" deep at a time and builds up in 1" layers every 12 to 24 hours. It cannot be used under 1/4" thick, and it is not a finished surface; top coat it with Bar & Table Top Epoxy on any table, bar, or countertop.

Many projects need two products: Deep Pour Epoxy for the thick section, Bar & Table Top Epoxy for the seal coat and final top coat. If you're not sure, tell us what you're making and we'll point you to the right one.