Originally Posted by oldtamiyaphile
Mortar and (presumably) wall plugs for things to screw into on a machine tool?
The epoxy would isolate the steel from the alloy, no corrosion issues. Mortar etches alloy on contact, and chances are it will end up on an external face no matter how careful you are, as well as shedding aggregate through any mounting holes.
There wouldn't be" corrosion issues" either way, like said unless you machine under water.
BTW "etching aluminum" is good practice before epoxying to it. And I'd rather get a little mortar "on an external face" and wipe it off with a damp rag, than get epoxy on the ways or "eternal face" as you put it.
I've had quite a bit of experience in aluminum for lathes and other machinery. btw. Here's one I built from scratch. No "wall plugs" just hand made patterns casting, scraping, etc.