Ok here is my Amp rack that I started over a year ago and then just left it sitting around collecting dust. I am about to install all my stereo stuff that I have bought over the past two years into my new car so I figured I better hurry up.
I First started with a piece of mdf as my base. Next I cut out some rectangular frames for the amps to sit down in. Once I had the correct size of frames to match the amp sizes I placed them on the base at an angle so they would be facing up slightly. Once the frames were in place on the base I then stretched the fleece over the piece making sure to get out all of the wrinkles out. layed down some fiberglass to stiffen the piece up and then cut out the holes for the amps to go into. After the piece was covered in fiberglass to give it its strength I then layed down the bondo on the entire amp rack. This is where you can make an easy job hard or a hard job easy. I have had plenty of practice with bondo and body work so I think I had a leg up on this step. Sanded the amp rack with my DA as much as I could and then hand sanded the rest with 80-180 grit paper. Here is what the amp rack looked after my first coat of bondo and shot with high build primer.
I then wet sanded down the primer finding all the high and low spots. For the most part it was decently straight and I only had to add a small amount of bondo to get the real lows. Here is what it looks like after wetsanding the primer and the adding some bondo to a few spots.
It is almost where I want it before I go back and spray some more high build. Ideally I would like to get it as smooth as possible before I spray primer again to avoid having to use the bondo, but as long as it is straight a little extra work cant hurt.