I am wanting to add a stain to an existing fireplace to darken the brick. What type of stain should be used? Are there any fire hazard concerns in doing this? Should a sealant be used as well?
Use an actual masonry stain or concrete stain. They are made for masonry surfaces. There isn't an issue with fire hazard when the stain has fully dried. Plus, a sealer isn't necessary. The masonry stain has its own water repellency built in. This will help with cleaning and dust control.
Interior Brick Stain
I had a dull beige brick fireplace and brick columns in my living/dining, and I used Behr metallic copper shear opaque glaze from home depot. Easy to sponge on, and looks warm and beautiful, especially with my amber lighting. I just did a light sponging with a sea sponge so some of the brick shows through.
It sounds like a great idea. Do you have any pictures you could post?
I have 20 year old brick on the outside of my house which has faded over time. I has tried several stains for brick to add more color to them but they faded within a year also. I finally used Minwax English Chestnut #233 wood stain on the brick and it looks great.