Personally I'd suggest starting over. Adapting a cabnet may work out but for a small amount more you could build something that works very well rather than just kinda works. MDF is very toxic I would avoid fumes from it that means fully sealed and then encapsulated fully I'd suggest epoxy.
I really believe there are fairly easy to work with materials that you could build a really great enclosure look at something made of PVCx. The same as 90% of the commercial enclosures on the market. komatex is one brand name.