As the title may suggest, what are the best types of wooden boards for attaching L brackets to and ultimately, firing pyro off? I am firing a display on aggregate (slate chippings) this year and obviously stakes are not an option. I would like something relatively thick (I want to re-use it in future), readily available and ideally, pretty cost effective. I have boards in my loft but have no idea what the stuff is but seems very dense and maybe suitable for what I need. I don’t think my board needs to be any larger than 180 x 100cm. Would thick, marine grade ply be an option? Cheers all for any suggestions!