I plan on building a tempest sonotube but I cannot find MDF. The local lumber and hardware stores sells something called sound deadening board, which they told me is used for speaker cabinet, but it is only 1/2" thick. Could I use this and glue two sheets together? If not what other kind of wood(that is relatively cheap)could I use for my endcaps? Unfortunately the closet home depot or lowes is 2 1/2 hours away.