Hy guys,

I have plug made from MDF that was CNC routed.

I've read that it's really hard to achieve gloss surface if MDF is not impregnated and "sealed" properly. It's hard for me to find products that are used for example in America and I have to take DIY approach. I figured that it might be possible to use polyurethane 2K varnish but diluted 20-30% so MDF can soak it easily.
Does anyone have similar experience? 

Also, I saw some DIY ovens made completely from support frame and MDF panels with rock wool between outer and inner panels. My plan is to build wooden frame, put 12 - 16mm MDF for outer shell, place rock wool around box from inside and than make smaller box that fits in from steel sheeting of aprox. 1-1.5mm thickness. I would make it so it opens from top side like a lid. I need curing temperatures of around 110-120°C (aprox. 250°F). Inner dimensions would be 160x70x50cm and I was thinking about 3 to 4 heaters of 1kW strength. 

Will this kind of build be ok to withstand those curing temperatures because I am afraid of oven catching fire? 

Also, I am looking for good PID controler with ramp and soak function so I can make proper curing cycle for pre-pregs. I've found some OMEGA controllers, but I am not quite sure what's good and what's not so please if you have suggestions feel free to write.

Thanks for your answers. 

It's plug that is made from MDF not mold. My plan was to impregnate the material with 2K PU clear coat varnish, then spray pain it with epoxy primer and then spray it with 2K polyurethane, sand it and polish it. Can I use diluted high temperature epoxy instead varnish? 

Since plug is MDF, can I make mold with high temperature gelcoat and epoxy that cure on room temperature, release plug from mold after 2-3 days and then post cure mold without plug in it? I would use very slow curing cycle to reach desired temperatures.

My concern is that if I leave plug inside mold for curing up to 120°C, PU varnish could ruin mold or MDF could warp since it's wood and resin based.

Also, what kind of heater do you recommend instead of regular oven heaters?