"Ignoramus9778" wrote in message
...
I want to, first, thank everyone for your suggestions, even for the ones
that I did not adopt. All of your ideas were valuable to me. I cannot
literally think of even one post which did not have some bit of useful
info or food for thought.

I am almost at the end of the work of making a generator enclosure and
soundproofing it. I bought lead sheet and attached it to plywood
panels. I need (and can) do a better job at sealing all holes and in
fact on one side I have not even completed the enclosure.

http://igor.chudov.com/tmp/onan/Diesel/Enclosure/

(I beg you to not xpost it to rec.woodworking)

I ran the generator today.

Despite this incompleteness, the enclosure appreciably reduces the
noise. At 10 feet, with the access door open, the noise is 85 dB. With
the access door closed, it is 79-80 dB. It also feels rather tolerable
to be around this working genset. I would not mind it working all day
long. It is much quieter than, say, my snowblower (87-89 dB).

Another good news is that, perhaps due to its weight as well as
vibration isolation by two used tires, the enclosure basically does
not vibrate.

I have hopes that when I am really done with this work -- have fewer
and smaller and baffled gaps and openings etc -- I can slash 3 or so
decibels from this, bringing noise down to sensible 76-77 dB.

The enclosure's panels are held by wingnuts and it is designed for
very quick disassembly, because it is relatively heavy.

Plans:

0. Finish the opening for cooling air intake and seal gaps better.

1. Weatherproof the enclosure, I will use epoxy on top and oil based
deck stain on the sides (to match the deck and shed nearby).

I did some web research on paints once that may suggest you not use epoxy.
Epoxy is tops at immersion resistance, ie., painting a bathtub.
It has poor UV resistance, which implies rapid degradation outdoors.
Suggest an outdoor polyurethane formulation, which also includes UV
inhibitors.