you think a 4mm thick piece of carbon is going to be stiffer then 7mm aluminium.... wrong you'd need like a 10mm thick sheet of carbon to get it as stiff looking at the shape of a vee booster, maybe less.. and also if you just cut a sheet, you'll fck up the carbon anyways, as its laminated layers in simple... so youll loosen them. like delaminate it. youll need to make a mould then layer the carbon into that, then compress it. so go buy carbon ribre weaved mat, i used to use 2x2 but what ever. get some half decent resin.... make you booster out of wood or something... vacuum form it.. or cover it in something to make a mould.. plaster? w/e then cut the carbon to the right shape then add resin, add carbon ad reson add carbon.. etc till its full... then compress it with something... pile weights on it or something... if you dont compress it it will be weak as fck or just get you aluminium and cut a pretty shape haha ebays your best bet haha i made a mountain board and kinda messed it up and all the edges were horrid, so i used a belt sander to sand them all down... iv never been so itchy in my LIFE! for like a week!, covvered in those red dots haha but i wore a mask so ddnt break any in luckily haha