Hi all, I’m new to DIY so apologies if this is a stupid question. I’ve made a desk/stand for our keyboard with a lift up lid. I was wanting to have a small shelf on the inside of that lid that folds down to 90 degrees and holds our iPad or music sheets etc. The shelf needs to sit at 90 degrees and not fall down with gravity (I.e. needs to be stiff so only opens when manually opened, not simply flopping down when the lid is open and closed. Is there a certain type of hinge I should be using for this job? Had a look in shops but all the hinges seem very loose. Thanks, Stuart.