Filter advice please on home made fume extractor

[HobGoblyn]

Hi all,

I’m in the process of making my own fume extractor.

I’ve been following the link at the bottom of this post.

I have now got everything except the actual filter medium as I’m not sure the way he’s doing it is the best way?

Basically it’s a deep plastic box with an in line mixed-flow fan, the exit going through the side of the box.  And a smaller box that sits inside with the filter medium in.

It’s just the design of this smaller box that I want advice on, the fan etc is already here, waiting to be installed. 

I’ve hopefully set the link to 19:36 where he shows how he does the filter.

He  uses two 30mm thick cooker hood filters on a cardboard gasket and covers the entire box with white wadding type stuff.

I was thinking that instead of cooker hood filters with cardboard gasket etc, permanently installing something like a couple of 200mm (8”) flanges (or smaller, maybe 150mm/6”) , like in the below pic,  but ones that allow me to put in metal mesh at the bottom of the flange.



Then I could simply fill with loose activated carbon and cover with hepa filter sheet?

I’d imagine in the long run this would work out a lot cheaper as those 30mm thick filters in the YouTube vid  are around £10 each + delivery and activated carbon for aquariums can be bought fairly cheaply?

(I will also make sure a hot knife is used to cut everything so the brittle plastic doesn’t shatter/break).

Anyone think my way is worse than his or can anyone think of a better way altogether?  Again I’m doing it roughly how he’s done it and already have everything except the filter medium.

Many thanks

YouTube clip below

https://youtu.be/JdrFsuAcm48?si=E_gZAbo8zq3uGZqv&t=19m36s

[thm_w]

Is he using any HEPA filtration at all? Didn't see it.
I would be tempted to use an off the shelf hepa filter and not some sheet because they are pleated which will increase the surface area. But if you have a really large surface you can drape it across maybe it would be fine.

The cheapest source of activated carbon is usually the grow filters you can get on amazon ($30 for ~2kg). I would avoid the pelletized fish carbon (appears to be less surface area), but if you can get the granular stuff for a similar price I'm sure its fine.