My Son and I are making my own version of Marc Spagnuolo's (The Wood Whisperer) end grain cutting board from padauk and tigerwood. He talks of several finishing options but recommends a 50/50 mix of wiping varnish and mineral spirits. After visiting HD and Lowes and seeing the only product they offer with the "varnish" the offer is Spar Varnish. This didn't sound like something yo cut food on, but I don't know. I scanned their oil based poly cans, suspecting it was varnish-based, but didn't find the word varnish.
I've googled the term and people talk of making wiping varnish by diluting poly and others refer to "wiping varnish (this includes polyurethane)", implying there are verious blends that fall under the wiping varnish name.
He talks about how, after 3-4 minutes of letting the end grain soak this up it may have soaked clear through the 1-1/4" board and how it is not film-building. This sounds like a good finish for a cutting board, protecting the inner wood from water also.
If poly will work and I understand it correctly then it you would dilute poly 50/50 with MS to make wiping varnish and then dilute that 50/50 to get his mix.
This would be a 75% MS / 25% oil-based poly mix. That sounds very dilute but I don't know enough to judge.
I understand that mineral oil can be used as an alternative however he indicated it required regular recoat while mineral oil is only required on this to hide cut marks that may eventually show up.
I could sure use some help here, planning a path forward.
P.S. There are lots of good free videos on his site: The Wood Whisperer Woodworking Video Podcast, Blog, and Forum