Engraving hours per batch of carbon?

[Raphael Weil]

Had started this thread because my carbon life seemed really short, but as it turns out I'm a dummy. Forgot I had put some rolled carbon media at the bottom of my trays, and they were clogged up. On the plus side cleaning out my carbon trays taught me about sifting all the dust out of those things. It was like a mushroom cloud of crud.

I guess since the forum is already made, I'll stick to the question. About how long is your activated carbon lasting you? I've seen some members talk about 6 months which struck me as incredible. I can only hope my goes that long.

[Glen Monaghan]

The life of your carbon is highly dependent on how much you use it (a couple hours a week or all day, every day?), what you are filtering, and how well you prefilter particulates. If everyday you are cutting a lot of plywood or mdf that smokes and puts out tons of resin and other VOCs, your carbon life will be fairly short, especially if you don't capture most of the particulates in the prefilter (and remember to change the prefilter often enough that it remains effective). Likewise, cutting acrylic can gum up the carbon pretty fast. But, if you aren't producing a lot of VOCs and you have good prefiltering, then yes, you could well go six months or more without needing to replace the carbon.

[Raphael Weil]

Hi Glen,

What sort of estimate would you say "pretty short" is assuming good prefiltering? I just added a Merv 13 right above my carbon, I think it's helping a lot. Hoping I don't need to go up to 15.

[Glen Monaghan]

As I said, it's all highly dependent on how much you use it and what you are filtering. As well as how much carbon is in your system since more carbon lasts longer than less carbon :^/ I only know that when I cut highly resinous wood that smokes profusely, my carbon bed gets coated and almost ineffective within hours, while engraving anodized aluminum and powder coat steel, which generates visible dust/smoke but nothing like you get from resinous wood, has little discernable impact on my carbon (so long as I keep up on replacing the prefilter, which gets really cruddy from the powder coat). This is one of those cases where you're just going to have to see how it works for your applications. You can monitor pressure drop across the various filters, measure air speed in the duct, visually inspect the filter media, weigh the carbon periodically, use a particulate and/or VOC measuring device to analyze the exhaust, and/or just use your eyes and sniffer to subjectively assess performance over time.