A while back I made a "quiet" box for our KwaiThong open-frame generator. 

 

Basically a 10mm plywood box lined with polystyrene foam and with a fan at each end to stop things getting too warm. It actually worked pretty well, not up to the standard of the real silent generators but it took the edge off the racket to the point we often didn't wake if the genset started in the night.

 

Sadly, time and the weather have taken their toll and the box is falling apart.

 

So it's time for a new solution, of course money is an object so whatever we can use that's "in stock" or was part of the old box should be used.

 

So I knocked up a frame of 1" square steel tube with a couple of 3" square verticals to support the doors. One wall and much of the top is part of an existing concrete structure.

 

The idea is to have an inner lining of 10mm ply (ex. formwork from a wall) and an outer skin of Shera board (left over from building a chicken house), the cavity would be filled with aerosol PU foam.

 

Fans would be re-used from the existing box.

 

Some photos, more as we progress.

 

 

 

 

 

 

 

You can easily buy sheets of foam to fill the majority of the space 

that would be a considerable saving on the foam in a can.

I would line the inside of the box with double layer of acoustic tiles & bubble wrap type of insulation making an acoustic box inside your wood box trying not to let them touch to reduce vibration from being transferee  - And Unlike foam they won’t retain water or humidity or make a nasty fire if they get too hot... Maybe add I layer of engine firewall insulation too...

Like this... 

https://www.lazada.co.th/products/elec-car-styling-car-hood-engine-firewall-heat-mat-sound-insulation-shield-mat-i255416245-s393916479.html?spm=a2o4m.searchlist.list.12.10d44c19UP2qAe&search=1

 

https://www.homepro.co.th/homePro/en/Construction-Insulation-PE-Foam-Insulation/SUNSHIELD-ALU-PE-INSULATION-90X400X1-CM/p/1002315

 

https://www.lazada.co.th/products/acepunch-10-packs-fiberglass-ceiling-tiles-panel-sound-absorption-acoustic-thermal-insulation-30-x-30-x-15-cm-kk1174-i315124474-s579666041.html?

Decouple your genset room from the house.

 

Vibrations pass through the walls of the genset structure into the walls of your house.

 

Place vibration absorbing materials under the wheels of your genset.

 

Vibrations pass into the ground, along and......through your walls.

 

https://drummagazine.com/diy-build-your-own-soundproof-home-studio/

"Unfortunately there is no quick, inexpensive way to get serious sound isolation. You need to have airtight construction, lots of mass around the perimeter, and decouple the room from the rest of the structure."

 

 

Some great thoughts, keep 'em coming ????

 

As noted earlier, the previous box was adequately quiet, so any improvement is a bonus. I'm not aiming for recording studio isolation just to take the edge off the clatter without spending silly money.

 

One issue we had with the last box (and the car) was the local wildlife making a home in the sound insulation, need to try to avoid that so I'm a bit reluctant to add nesting material unless it turns out to be absolutely necessary.

 

Moving right along, both fans are now installed, this fan is an industrial ventilator with a (not very well) home-made duct.

 

 

And we start on the doors. After reviewing the available materials I decided that the doors wouldn't be hollow, they are a very tough bit of 20mm ply, not sure what I bought it for but there's pretty well a whole sheet. The Shera is nailed (air nailers are a very handy beast too) to the ply for extra mass and sound deadening.

 

 

Due to space restrictions (a tree) in front limiting the swing space the doors are split into a 280mm and a 460mm section hinged together. The rather odd sizes also try to make best use of the limited amount of Shera panels that are in stock.