The spec says you can work on materials that are up to 2" thick - it never says you can cut through anything that thick. Now, a number of folks on here have found you can actually do thicker materials, but in every case it’s involved some serious trial and error. The “verdict” is, it depends - on the material, and your desire to spend the time to figure out what works on the material you’re trying to cut through.
The Matrix is here: https://community.glowforge.com/t/community-glowforge-tutorials-table-of-contents/, it links to many many posts in the forum. I do not believe any of those links are specifically for thick material. You can start with the settings in this thread - but unless your piece of material is identical to @melissa3’s it’s not likely to work exactly the same - so you’ll need to test.