The blues is an art form established in the deep south at the turn of the century and today forms the basis for a lot of the music we hear. There are two types of Guitar Blues Scales I want to discuss here. The first is the minor blues scale. This is a six-note scale that consists of a flatted 3rd, flatted 5th, and a flatted 7th.
The minor blues scale in the key of C contains these notes: C-Eb-F-Gb-G-Bb. Looking at this scale, you’ll probably notice this is a scale you’ve seen referred to simply as the blues scale. The blues scale and the minor blues scale are one and the same. You can also see that this is a minor pentatonic with the flatted 7th added.
The major blues scale can be built by starting with a major pentatonic and adding a minor 3rd (or a flatted third). The notes for a C major blues are C-D-Eb-E-G-A.
I use the key of C to illustrate these two scales, but the same formula can be applied in any key. Scales are nothing more than formula. Once you know the formula, you’ll be able to consistently replicate the results.
Blues Scales
The two blues scales I mentioned above are the meat and potatoes of the genre. There are some variations, but they are used infrequently and to varying degrees. There’s the nine-note blues scale (1-2-b3-3-4-5-6-b7-7) that achieves its blues sound by allowing the normal third and seventh degrees to play off the flatted degrees. Chances are you won’t be using this one often, but know it does exist and is considered a “blues” scale.
Practicing guitar blues scales is simple. There are five positions that allow you to move the blues scale around the neck of the guitar. Practice linking these five positions together until you can cover the fretboard, then start experimenting with some movement by jumping around the positions. It might seem a bit tricky at first, but once you’ve committed the positions to memory, it will start to come naturally.
Now add some blues techniques like finger slides, tremolo, and slow bends to start bringing the notes of the blues scale to life.
Blues Scales
The two blues scales I mentioned above are the meat and potatoes of the genre. There are some variations, but they are used infrequently and to varying degrees. There’s the nine-note blues scale (1-2-b3-3-4-5-6-b7-7) that achieves its blues sound by allowing the normal third and seventh degrees to play off the flatted degrees. Chances are you won’t be using this one often, but know it does exist and is considered a “blues” scale.
Practicing guitar blues scales is simple. There are five positions that allow you to move the blues scale around the neck of the guitar. Practice linking these five positions together until you can cover the fretboard, then start experimenting with some movement by jumping around the positions. It might seem a bit tricky at first, but once you’ve committed the positions to memory, it will start to come naturally.
Now add some blues techniques like finger slides, tremolo, and slow bends to start bringing the notes of the blues scale to life. 
