Don’t you hate it when they get mad you for doing your job? Alas, we’re always the bearers of bad news. (Oh Davis, you’re such an Omniscan holder…)
After a long hitch offshore and many UT readings later, I decided to patch together this short explanation of exactly how the echo-to-echo (or E-E) technique is used to measure "just the metal", and ignore the paint. The difference between my rant and the myriad of others available is that the article is really short and illustrates the technique with simple math. Print it out and hang it on your office wall, you'll be the envy of all the nerds in trailer town!
Frustrated with interfering echoes, I design my own PAUT calibration block. The holes are spaced far enough apart and the ends tapered such that reference hole and corner echoes are isolated from each other, allowing for a clean sensitivity calibration up to 6 inches of sound path. Not bad for a 3/4" block.
Proud to announce that same little calibration block is now available from the fine folks at PH Tool. Click here.