Attaching the crown molding

Making the mantel deeper. I wanted a 15″ board but HD didn’t have any so I bought a 3″ to attach to my 12″. But I also had to buy the clamps, which set me back 30 dollars. So, I removed the packaging very carefully and tomorrow I can take them back and return them.

I just dropped a piece of crowd molding inside the cavity of the fireplace where I can not get it. I should be upset, but the molding is at such a strong angle that cutting it on the 45 wasted three inches each time, so I already realized I would need more (because I buy with five inches to spare, but four cuts translated into 12 inches) So whatever.