Here's what I usually do:
Write what I want to write in an electronic notepad or word or something and then cut and paste to post.  Gives you all the time you need.

What I would like to see is a way to block seeing posts of certain people I choose to block.  Now that would be really helpful.  

I don't see why we can't just edit or remove our own posts at any time.

Two words:
swiss cheese
I don't want to see the public record (that is CathInfo) turned into un-intelligible swiss cheese as people leave, go astray, get sucked into various cults, etc.
Just think before you post and you'll be fine. I never say anything I would be ashamed about if God knew (because He does!)

Back in 2006, when we had single-digit members, we had one member get upset and go through and edit all of her posts down to a single "."
Fortunately many of those posts were indexed in Google, so my wife and I were able to restore them (we needed the content at the time!) and the member got over whatever mood she was in -- but it taught me a lesson about giving members the ability to perpetually edit their posts.

Seriously, if I had a penny for every bit of experience or life lesson I gained from running CathInfo, I would be able to buy another house and pay cash for it.

[...] I know I can't be the only one who wishes this could be changed to at least 10 or 15 minutes.

I'm among them.  Some computing delays are beyond my control.  I don't know what combination of browser vs. operating system deserves the blame.  In some instances, 30 minutes would not be too generous.

Maybe this poll will help nudge him to expand the time to edit.  I doubt it but never hurts to ask.

Except that your poll is badly worded:

How long before the cement dries?

Sigh.  Wording does matter in conducting polls.  For future reference, the grammatical tense, voice, and mood [†] of your wording makes it look like a question of fact, i.e., a terse quiz about what limit is currently implemented for the "cement".  It's inexplicably lacking any words indicating a request for the wishes of CathInfo members: No "would you like",  or "... prefer",  or "... want",  or "... wish",  &c.  And C.I. displays your poll question--ready for clicking one's vote--physically above all context except the "I protest" of your subject text.  So you might have ruined your own poll.

But!  Matthew has rendered that possibility moot, by getting out in front with his favorable decision, as posted in the past hour (12:41:02 CDT).

I suppose that from Matthew's perspective, he could credit you with the charity not to have indulged in Greenpeace-like blatant bias, e.g.:
•  Do you approve of the inhumanely brief time-limit by which CathInfo inexcusably cripples corrective editing by its thoughtful members of their own postings?

-------
Note †: Present, active, indicative, repectively.

Thank you Matthew.

This really helps especially for busy moms who have to run and change a diaper, or for old people who can barely see the monitor.

I wish we had 30 minutes in order to correct spelling, grammatical, and constructional errors in our compositions. That would keep the prescriptive grammarians among us happy. We want happy campers, don't we?

Added a comma for accuracy.   (I'm totally kidding)

:D  Let's see what Nadir or AlligatorDicax have to say on the matter.

Nadir, where art thou?

How about raising it to an hour to account for "poster's remorse"; so the hot-heads and those who are temporarily deprived of intellect have more of a cushion before their public shame becomes permanent?  (Mea Culpa)