Ceiling in the dining room has crack from one side to the other. I just removed the popcorn and old repairs (NOT DONE BY ME) It was paper tape w/ some compound to fill & smooth.

Crack is maybe 1/8 inch in spots with the crack going thru the rock lath. I know how to "V" the crack and clean it out but my question is exactly what compound do I use to FILL it. I do not want this coming back. Can not detect any movement in the rock lath when I push on it.

I read DURABOND or gypsum/sand plaster. Confused. Anything I can get from Home Depot to do this?

Thank you so much, Kathy

Easysand is another setting product and as the name implies can be sanded.

Both products have a number after them that is the nominal setting time.
They harden be chemical reaction, not drying out like the pre-mix mud in buckets.

1940 was not commonly skim coat plaster, but 2 coat plaster.
Look at a receptacle.
If the plaster is about 3/5 inch thick with gypsum backer is it 2 coat.
A skim coat wall will be barely more than 1/2 inch thick.

If the crack is stable and not moving, mesh type drywall tape and Easysand should make a good repair.

Be sure to moisten the edges of the crack to get a good bond.

The final patch should be at least 12-16 inches wide.