transom replacement
 

I posted this in the fiberglass section as well, but figured some eyes might see it here that dont normally wander over there.

I am gathering up info to start replacing the transom on an 86 formula f3ls. I have read thread after thread and FEEL like i have a decent grasp on what I will be doing. My plan is to cut the old one out (which is what the point of this thread is) and go back with 1 1/2 oz mat, 3/4", 1 1/2 oz mat, 3/4", 1708,1708 all with vinyl ester resin from us composites. That being said my question is really rather simple. What are some of you doing to remove boxes and such from the area when the depth is unknown. For example, in the pic below, the area circled in yellow. I have no idea of how deep this box is so it would be foolish to go to town with a saw or something. what are some solutions you all have come up with. I am also open to suggestions for respirators!
http://img.photobucket.com/albums/v6...2/8d037927.jpg

Take things out a little bit at a time. Cut straite back on that and then work down to the bottom. If you go slow you will see what you need.

Jon