Ephesians 2:18, read in its overall Biblical context with verses which teach that God is One, definitely teaches the doctrine of the Trinity.
Also, Matthew 28:19 presents the doctrine of the Trinity ("baptizing them in the Name [singular] of the Father and of the Son and of the Holy Spirit" [hence, we are forced to understand God as One Being of Three Persons].)
And of course, there is the Johannine Comma.
There are many other examples of this sort of solid proof of the Trinity of God. Of course, I wouldn't expect the average RC to know any of this. (It is standard Protestant knowledge; but then again, Protestant pastors carefully, methodically teach the Bible!)
They are there, but not defined as it is taught. And I see it didn't take you long to throw in an insult about the "average RC" as if we're a bunch of morons. You guys are the ones who can't even be honest enough to admit who promulgated the doctrine. And since you clearly think that scripture lays it out crystal clear, maybe you can tell me who your Authority is for you interpretation. I have asked wrigley and cc, but so far I haven't gotten an answer. How do you know your using inspired doctrine since it was compiled by Rome?