@ bassbandit25
There are three options , that I can think of , ..........either wood , PVC decking or resin !
Wood is THE tradional lure material , easy accessible and easy to work with , but has the disadvantage to be vulnerable to water sepage , especially on lures like swimbaits with its multiple joints and/or hinges .
There are many types of wood to choose from , many different grades of buoyancy and densities(could be important for the action of a lure and the trimming with ballast) .
PVC decking seems to have become the latest hype for swimbaits ,..... it is extremely buoyant , cuts , carves and sands very easy and has the great advantage of not soaking up any water(its just a plastic material) .
But on bigger baits it would require PLENTY of ballast weight to render it to sink/suspend or even float up upright , could provide issues about sufficient space for all of those weights .
Some guys in here also do cast their baits from resin , .......I do not know much about that except that to me it seems to me to be the premier league in lure making , ............you'd need to make a master lure and make a casting mold from this master , after you could cast quite a few clones with that mold , ........but as said before , I do not know much about it .
If you look around in here thoroughly , utilizing the search function , you could spend hours and hours with reading tons of info and threads about swimbaits and their construction , ..........there even is at least one tutorial in here .
Just go ahead and have a look , .......if you'd have further specific questions , .......I am sure , those would gladly be answered !
good luck , diemai