I had always been rather pissed off at how quickly my Shopvac filter clogged up thus reducing the available suction that the vacuum could provide. Finally, I got annoyed enough to do something about it.
The main problem is in the basic design of the inlet air deflector which directs the incoming air (and dust) from the filter down into the container. Unfortunately, the dust and dirt is constantly stirred up by the downward flow of air, creating an even worse situation for the filter.
My idea was to direct the incoming air sideways, creating a cyclone effect in the container. By doing this, gravity would tend to keep the dust and dirt in the bottom of the container away from the filter.
The following photos show what I did and doesn't require a detailed 'Instructable'. The ABS male
1½” adaptor was a tight press-fit into the original air inlet connector and didn't require gluing. The same was true for the 90 ͦ elbow.
I could have simply modified the original deflector to point sideways, but it was such a poor fit and in my opinion would still cause continued stirring up of the dust in the container.
I have used the Shopvac quite a few times since this modification and am pleased with the results. The Shopvac has maintained greater suction than before.