Is there anyone that can give some advice on how to put in a stringer for EPS foam. I have a block of it that needs to have a stringer to be put in. I just curious on the process of dong so. What is the best type of wood to use and how exactly to glue the foam to the wood (i.e. what kind of adhesive). The other question is can epoxy be laid up like polyester resins or is it mandatory to vaccuum bag it. Any other suggestions are welcome. Thanks in advance Jason
Is there anyone that can give some advice on how to put in a stringer for > EPS foam. I have a block of it that needs to have a stringer to be put in. > I just curious on the process of dong so. What is the best type of wood to > use and how exactly to glue the foam to the wood (i.e. what kind of > adhesive). The other question is can epoxy be laid up like polyester > resins or is it mandatory to vaccuum bag it. Any other suggestions are > welcome. Thanks in advance Jason You can glue up an epoxy stringer with almost any glue except polyester resin. Epoxy resin works good, and elmer’s white glue works good. For stringer material, white cedar is strongest, but grainy. Basswood is easier to work with, and still strong. Redwood is heavier, and harder to clean the dust out of the blank pores, but very pretty. You can lay up epoxy just like polyester, with no vacum bagging. You need an extra layer of fiberglass on each side of the board. Don’t forget to sand the lap area between layups, and to sand all the glass before hotcoat. Dry epoxy surfaces are slick. Nothing will adhere to them without sanding. Hotcoat with polyester resin. Epoxy yellows and degrades in sunlight. Polyester resin resists sunlight. Good luck, Noodle
You are going to have to make a hotwire. Peter Rijk had a diagram of one he made (I know info about it is in the archives). You are also going to have to make several rocker templates. From what I understand you clamp or fasten your rocker templates to the sides of your block, then run the hot wire over the top and the bottom of the templates. After that you cut your blank down the middle (from nose to tail), take your stringer (whether it be basswood or pvc or whatever) and clamp/glue both halves to it. I buy my eps blanks already ready to go (so I can’t give you specifics, but I have seen the cutouts before and after they have been ripped in half). I can’t find foam in my area cheap enough to warrant experimentation. Peter has also posted some info on vacuum bag type glassing. He claims it is pretty easy, but I have not tried it. I use the traditional layup method, however unlike Noodle I don’t use any poly resin (epoxy resin only). Good luck.
the previous posts are on the money.If you get a foam block that has been lazer or computer cut after hot wireing the rocker cut the block down the centre then put the hand cut sides to the outside and glue the lazer cut sides to the stringer.I use 1/4" t band stringer glued in with epoxy. I’ve glassed all my styro/epoxy boards without vacuum bagging. My lay up is flat weave 5oz with twist weave 6oz over it on the bottom.Then on the deck I use 4oz twist weave down first then flat weave 5oz then twist weave 6oz over the top.I pigment my resin to get a solid colour. After laminating I wait about twenty minutes then i use a small amount of resin to skim over the glass this fills any pin holes as the styro sucks in the resin.You don’t want any pin holes cause your polyester will go straight thru and eat up the styro.I also use a hot room with a constant temp of around 28degrees celsius to keep the board in after it has gelled.I leave the board in the hot room for 24 hours between sides then for 48 hours before I sand and hotcoat when you sand the lam make sure you get all the shinies so your polyester adheres well. I have had no delam problems when I do things this way.There’s no short cuts with styro and epoxy but your finished product is very strong and bouyant and in the 10 foot range should be around 4lbs lighter than a standard polyurethane/polyester board.The last board I made came in for repair last month, it was 9 months old and did not have 1 deck depression. Good luck I look foward to hearing your results… ps.If you plan on putting a fin box in your board cut your legrope plug hole first but don’t put it in until after the fin box. Cut your hole for the fin box as small as possible to accomodate the box. Then pour some epoxy into the hole. I put 1 layer of chop strand mat and one layer of 6oz well over sized over the hole then push the box in to the hole.Once I’ve taped the fin into position and set it straight I make a dam out of tape and pour more resin into the dam keep an eye on the box as the styro will suck the resin in and you will need to top it up a couple of times.Also by keeping the box hole small the epoxy won’t heat up too much and melt the styro and the gas it develops can escape thru the plug hole so as not too blow any glass off the board. Last of all put your plug in as normal, this small amount of epoxy wont heat up very much and shouldn’t blow…