English has stupid spelling rules. I say this as someone who has never had much trouble with spelling. What would be nice is if we made sure to honor those words that actually follow the basic rules. The most glaring example is primer. In the United States we prefer to say PRIM-mer. Perhaps this is the result of American feelings of inadequacy at being a rough and wild outpost of the British Empire some 200 years ago, so we thought PRIM-mer sounded more erudite. Well, despite their frequent mutilation of the language (i.e. they call a broiler a grill), the British do choose the more sensible pronunciation of primerand say PRY-mer. This pronunciation both honors the word history and keeps the spelling sane. (See http://www.bartleby.com/64/C007/0150.html)
Whether you are talking about painting a wall with primer, or taking a primer on how to be a prim stick in the mud, you say it the same way: PRY mer. Say it a few times with increasing confidence. That's right, PRY mer. Good! Feels better now doesn't it?
A little Explanation
Primer comes from the verb to prime, to prepare something for some specific use, be it a wall, a mind, an engine, or a pump. Other words closely related to this word includeprimary and primal.
Primer does NOT trace its root through the adjective prim, which describes the state of being stiffly proper and mannerly. When you say PRIM mer, you are saying the adjective that means "more stiffly proper and mannerly."
A little background
As a point of etymological clarification, both primer and primultimately share the same Latin root for "singular or first", but the got to us from very different routes. Prime apparently is traced back to Middle English and directly to Latin probably via the Church. Prim comes to us from Provençal by way of Old French and my guess is that it probably arrived in England through trade or as a legacy of the Norman invasion. (See http://www.bartleby.com/64/C007/0150.html)
Perhaps it makes sense to say PRIM mer when talking about a learning exercise, since learning is associated with improving ones station, but it is dumb, technically speaking.