Figured it out!
After a day of testing and struggling, I figured out how to use the mask feature with our swimming entry times.
The keys include putting the times in as a HTML Type as Text and not a Number. When using a number the point fails and the tenths can't be accepted. I figure HTML Type Number is only WHOLE numbers and not fractions of seconds.
The second key is to allow the brackets, curly brackets and wild-card star, (generally found on the computer keyboard above the number 8) to work in the field with the check-mark on. The head scratching was over. No pipes. I tried them all, it seems.
Desired output in the test set from Shady Side Academy
You can see the form in action on the Time.CLOH.org site.
What not to do too.
As I was scratching my head, I built a sloppy form. I call these test pages and forms, sandboxes. You can surf over there and see what I was toying with along the pathway.