# designing airtight filterbox - what thickness of sheet metal to use?



## wwwfarmer (11 mo ago)

Hello everyone!

I am designing a filter box for H4,F7 and H13 filter for the house I am living in. The filters will be placed between air intake and central recuperation unit. I was forced to use very large filters with width-height dimensions of 610x610mm to minify pressure drop in the ventilation system. Expected air flow is 200m3/h. Normally, just H4 and F7 is used, but such combination filters out just 65% of pm2.5 particles. Unfortunately I live in a valley with constant smoke from combustion so an upgrade is needed.

This is the design I came up with:














And these are filters that go in the first slot (G4 and F7) and second slot (H13). H13 filter comes with a foamy gasket, to G4 and F7 I applied it myself.















Ventilation systems are typically made of riveted galvanised steel, but since I'd like to make it air tight I am thinking of using Aluminium instead (AL 5754 H22) and weld the critical parts together. These are weld locations:
































Filter box dimensions without cone and cylinder part are around 616x616x580mm. For the main body I was thinking of using 2mm sheet and 1mm for the cone and cylinder part. I will outsource the welding part but I need to decide on the metal thickness. Do you think 2mm for the main body is too much? Would 1.5mm suffice? What about cylinder and cone, will 1mm thick AL 5754 H22 make it too difficult to shape into cone and cylinder by hand? What is the minimal thickness an experienced welder is able to weld together?

Thank you for your help!


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