DIY Macerator

There's been a number of home-brew RV macerator fabrication posts. They're all similar except for the approach they take to interface/connect the 3" RV flex hose to the 1 1/2" hose/barb input of the marine-type macerator. Some cutoff the entire hose/barb (or leave it intact) and use a hose-clamp to mount the 3" RV flex hose to the outside of the entire pump housing. It works, but it tends to collect a bit of "stuff" inside the 3" RV flex hose because the opening goes from 3" to 1 1/2" abruptly---everything just hits a flat surface and tends to collect. It's even more of a problem if the 1 1/2" hose/barb is left intact inside the 3" RV flex hose.

I found a 1 1/4" flexible sewer coupling (FSC) an almost ideal fit for the macerator's 1 1/2" hose/barb input. Also found a 2" FSC will fit inside a 3" RV flex hose almost perfectly (you'll need a small piece of PVC pipe inside the FSC to support the 3" RV flex hose clamp). Not sure if they make an FSC that tapers from 1 1/4" to 2" FSC. If they do, that would be the ideal solution. I couldn't find one, so I coupled together a 1 1/4" - 1 1/2" and 1 1/2" - 2" FSC. These two combined taper from 3" to 1 1/2" (similar to the Flojet)--with little flat surface--less chance of "stuff" collecting on the intake of the pump housing.