Attaching rubrails, gunwales etc

Hello,
GRP Newbie here. How to attach a wooden gunwale or color break line to the outside of a grp hull? How do the guys in production do it? If it's glued, what glue? and doesnt it all squidge out the sides so messing up the gelcoat?
There is no evidence of screw, rivet or bolt holes on the boats ive looked at though...
Many thanks in anticipation,
Matt

 

Someone must know how they do it?
Please!
Matt

 

I'm not a boat builder... but I've seen pictures of it being done.... Usually there are stainless screws that go through the hull and have either a nut and washer on the inside or a stainless lag strip instead of the washer. The screw head is hidden under the rubber strip on some models of rub rail.. on some the head is visible. I've seen two component epoxy used to hold it in place along with the screws. If the rub rail is at the seam where the deck meets the hull... then a specific epoxy that works with the resin is used along with the screws. Sometimes if only a sealant is needed ,3M 5200 is used. In either case.. the area where the excess glue or sealant "squidges" out is masked with tape and paper.. So that the excess squidges onto the tape and paper and not the hull side.... Then when the material has gelled and won't run anymore ... the edge is scored or cut with a knife and the tape and paper is removed. If the excess is allowed to cure... you will have a fight on your hands removing the tape and paper. So it must be removed before the material has hardened.... 5200 is rubbery so it can be cut when cured... as long as it isn't too thick.. Epoxy will leave a hard bead that will give you a real challenge. Good luck.

 

They are screwed from the inside with self-tappering screws and the wood pieces are at same time glued with polyurethane rubber sealant.

regards
Henrik.A