Thought I’d try out one of the exhaust silencers on the ShopVac to see what difference it could possibly make.
The design is pretty basic – a tube with an opening and exit the diameter of the exhaust of the vac, and a wider diameter between with a foam tube inside.
When fitted to the outlet of the ShopVac, there was a noticeable difference, although not particularly significant. The noise is more the motor than the exhaust it seems. Nor does the silencer work particularly well in its as-supplied state.
And yes, given how simple the design is, you could easily make one at home.
What I am thinking is to block the outlet, and cut slots around the circumference instead, and see if that makes more difference. I’ll research that another time.
Out of interest, I measured the sound levels in the workshop.
Outside (at the time): 40dB
Inside workshop: 38dB
1m from Sherwood dust extractor: 77dB
1m from ShopVac (no silencer): 86.5dB
1m from ShopVac (silencer): 84dB