Water based or oil based primer, which one should I be using?
Today's water based primers are remarkably resilient and can be used in a wide variety of applications. However there are instances where an oil based primer is clearly superior or even necessary.
When is an oil based primer necessary?
Make sure you use an oil-based primer (or shellac based) when you need to lock in odors like smoke or mildew. These primers have a strong odor of their own--so make sure you have good ventilation and a respirator--however the odor will dissipate as it dries.
Oil-based primers also tend to be the best at blocking out tough stains. However, there are some good water based primers that can do this as well and have a more tolerable odor during application. In this case oil based is a good option but not the only option.
Another instance when oil-based primer is necessary...
If you're painting bare wood and you don't want the grain to raise at all then use oil based primer. If you're painting fine woodwork or casework that requires a smoothe finish then a water based primer can cause the wood to swell and it will accentuate the grain when it is undesirable. Oil based primer will avoid this problem.
In most other instances a water based primer will work just fine and they tend to be less expensive. The exception to price would be when purchasing some specialty primers that I'll detail in a later blog post.