Never heard of anyone making a black locust backed erc with poplar in the middle before..you might be the first...lol
let us know how it works out for ya...I picked up some locust lumber from a local mill last year,but I wouldn't use it for backing strips...tough to find locust lumber ,and let alone good enough for backing strips...what orientation is it? Chased ring? Flat sawn,rift,quarter sawn? Jus curious...hopefully the locust isn't too strong for the erc...its strong tension wood..I'd maybe think about trapping it some? Need to know more stats and info tho...please do tell