I’ve noticed it a couple of times now - particularly with 1/4" MDF, the seal on my glow forges lid isn’t doing anything. While the fan is certainly working and is venting smoke outside - there’s also a lot leaking out the seams of the lid and filling the room with smoke.
Has anyone else experienced this or have a solution short of taping the seams when in operation?
You need to clean the fan. Whether it’s a less significant cleaning of the grate and what you can with a pipe cleaner or similar, or using the spray.
It’s not going to get better on its own.
The smoke is leaking because it has nowhere else to go. The unit normally operates by creating a negative pressure environment - when the fan and grate get blocked up, it’s not able to expel enough air through the exhaust port. That air has to go somewhere, so you’ll see it escaping out of the lid and front door.
The exhaust fan grill will eventually face load and restrict airflow to the point that the intake fans will pressurize the interior, and smoke will start being pushed out every crack in the machine. The exhaust fan moves more CFM than the intake fans so as JB said there should be negative pressure in the machine. You can easily clear it by poking the buildup with anything that will fit the holes in the grill, and suck it out with a shopvac from behind. It is essentially ash.
Just as my warranty was about to expire, the exhaust fan developed a hard vibration So I was compelled to remove it thinking the fan was bad. It turned out the fan blades were imbalanced from buildup. While I had the left side of the machine open and the fan out, I decided to remove the fan grill and eliminate the maintenance of cleaning the fan grill. Removing that obstruction also increases airflow.
This is not an official recommendation. You don’t want to do that if you have any warranty left.