I wan‘t to make a fiberglass kayak after I mold it and soak it in the resin and take it out of the mold do I have to seal it somehow?
Fiberglass is relatively porous, but if you coat the inside of the mold with Gel-coat, then lay up the cloth/impregnated with resinyour done. Gel-coat is a filled (pigmented) polyester resin, which is the same basis for RPG (fiberglass). You can spray it on after molding or you can use other color coatings like Urethane coatings. Epoxy is normally to brittle, but you can use it in some applications.
psssssst even cars have directional tires it has to do with the tread design and the way the tire is made google it DEE DEE DEE
Richard C has the right idea, spray gel-coat in the mold and then do your glass layup. No gel-coat is heavy but you will be using a small amount. You can also spray the mold with a Duretec sanding primer and then do your glass layup. Once out of the mold you can spray finish to any color you wish. Third options is to do glass layup, remove from mold spray with a sanding primer and them spray to desired color. Fourth is to remove release agents and clear coat with epoxy. There are coloring agents that you can get for epoxy but the range is very limited compared to paints. Remember to remove all mold release agents primer to sanding and paintwork.
In areas like the bilges of boats that might be wet for longish periods - fishing and other workboats, open boats etc. - it is always worth painting the inside glassfibre surfaces with something appropriate. In such cases anything is better than nothing. But on a kayak it is completely unnecessary for waterproofing purposes. If it is an open kayak, a coat of paint on the inside will however not only improve its appearance but can actually make the vessel more comfortable, by providing a barrier to the glass. Which is an irritant by touch. And on the exterior - the gelcoat - just apply lots of wax polish after you release it. The whole point in the first place, of the gelcoat, is to provide the glassfibre lay-up with a waterproof barrier. And if you want it to stay looking good and keep it in good condition, as well as highly waterproof, you can do this regularly. As you might on a car. Edit: (Post-digit) Note: I have directed my answer to and therefore addressed your specific question, which you have quite correctly posed, concerning what you do AFTER you remove it from the mold: after I mold it and soak it in the resin and take it out of the mold. I have avoided becoming sidetracked into advising you on how to go about the lamination process itself - it is not what you asked! ;-) -|--)
