Thanks John and Keith, it looks like I'll be going back to each seam and resealing them just to try and narrow it down. Keith, I've gone outside, especially when we're engraving wood, and there's no doubt it's being pulled outside (heavy smoke). There's no visible smoke inside the garage, just the smell. Now I know some of that smell is coming from the wood itself once it's removed, same as the acrylic, but I worry that it's too much. I might have my industrial hygiene buddy come and run the meter too. It's really the acrylic and metal engraving I worry about. The Chromium and Nickel fuming is a pretty bad thing from a health standpoint.
John's suggestion is a good one for running a separate clean air intake. And yes that fan should be good, it sounds like a damn freight train. I really need to invest in a similar CFM, lower decibel unit.
Trotec Speedy 300 - 80 watt
Synrad 30 Watt - CO2 Galvo
LaserStar 3804 - 50 watt fiber - SPI Source
Tykma Minilase - 20 watt fiber - SPI Source - (MOPA)
CorelDraw X7