Love all the MDF vs whatever ply threads. But I thought I would try something a bit different.
I am fitting 8" type Rs in my kick panel area. To avoid cutting metal, the 8" will need to be nearly flush with the inner sheet metal of the kick panel area. If the 8" protrude too much, the magnet and basket of the sub will block airflow into the kick panel area. This problem can be solved by cutting away sheet metal for clearance, or by mounting the 8" flush. I do not wish to cut sheet metal in this critical area of the car, so flush mount is the only solution.
The sheet metal from the floor board to the firewall crossmember (just below the windshield) of the kick panel is fairly thin and flexes with hand pressure. So, obviously this entire area will need to be reinforced and stiffened up. 3/4 MDF would do the job, but 3/4 inch is thick enough that it will cause the airflow issues mentioned above. Yes the lip can be beveled for increase airflow, but that again will force me to cut sheet metal so that the bevel continues into the kick panel.
I could make a large baffle out of 1/4 aluminum plate, but it is expensive stuff. To cover the area would cost >$300 for 6xxx series aluminum. The sheet metal of the kickpanel is not flat, there is a lot of creases in the metal. So, even with plate aluminum, the voids between the plate and the sheet metal of the kick panels would need to be filled to stop flex. The only thing that would work well as void fill would be epoxy with filler. Epoxy is expensive, and there is no room for error.
So, when at the local big box, I happened to spy some cement board. 1/4 stuff is dense, strong and stiff. For $10 a sheet I am going to give it a shot. I will use polyester resin and mat for void filling between the cement board and the sheet metal. The cement board appears to be porous enough to allow some penetration of the resin. This should provide a good bond between the fiberglass mat and the cement board. Fasteners with some flexible adhesive will be used to mate the board to the sheet metal of the kick panel.
Weight of the 1/4" cement board vs the 3/4" MDF per unit area is about the same. The cement board may be a bit heavier.
So that's my plan. Cement board plus poly resin and mat to make a large baffle to cover the entire kick panel area = Flush mount for the 8", good clearance for airflow into the kick panel, void filling to prevent the sheet metal from flexing.
Should be interesting ;).
I am fitting 8" type Rs in my kick panel area. To avoid cutting metal, the 8" will need to be nearly flush with the inner sheet metal of the kick panel area. If the 8" protrude too much, the magnet and basket of the sub will block airflow into the kick panel area. This problem can be solved by cutting away sheet metal for clearance, or by mounting the 8" flush. I do not wish to cut sheet metal in this critical area of the car, so flush mount is the only solution.
The sheet metal from the floor board to the firewall crossmember (just below the windshield) of the kick panel is fairly thin and flexes with hand pressure. So, obviously this entire area will need to be reinforced and stiffened up. 3/4 MDF would do the job, but 3/4 inch is thick enough that it will cause the airflow issues mentioned above. Yes the lip can be beveled for increase airflow, but that again will force me to cut sheet metal so that the bevel continues into the kick panel.
I could make a large baffle out of 1/4 aluminum plate, but it is expensive stuff. To cover the area would cost >$300 for 6xxx series aluminum. The sheet metal of the kickpanel is not flat, there is a lot of creases in the metal. So, even with plate aluminum, the voids between the plate and the sheet metal of the kick panels would need to be filled to stop flex. The only thing that would work well as void fill would be epoxy with filler. Epoxy is expensive, and there is no room for error.
So, when at the local big box, I happened to spy some cement board. 1/4 stuff is dense, strong and stiff. For $10 a sheet I am going to give it a shot. I will use polyester resin and mat for void filling between the cement board and the sheet metal. The cement board appears to be porous enough to allow some penetration of the resin. This should provide a good bond between the fiberglass mat and the cement board. Fasteners with some flexible adhesive will be used to mate the board to the sheet metal of the kick panel.
Weight of the 1/4" cement board vs the 3/4" MDF per unit area is about the same. The cement board may be a bit heavier.
So that's my plan. Cement board plus poly resin and mat to make a large baffle to cover the entire kick panel area = Flush mount for the 8", good clearance for airflow into the kick panel, void filling to prevent the sheet metal from flexing.
Should be interesting ;).
