10'8" x 34" x 4"
Building my first board out of XPS pink foam. 2 questions so far: 1. The more I read I keep seeing XPS delaminates easier than EPS. Is this build a mistake or is there something I can do to help prevent the fiberglass from delam? 2. Since this is a closed cell foam, are vent plugs still necessary to install? Thanks for the advice. Any other helpful tips are welcomed
I built a 5'9" fish using
I built a 5'9" fish using this same method for the blank. For your Questions:
1. Keep your final finish of the blank rough. I cant remember exactly what grit but I did a quick "rough up" pass over everything before glassing wtih like 60 or 80 grit sandpaper. I learned that trick from an old XPS build thread, so search the General Discussion forum.
2. I didn't vent mine, but it is relatively small and I glassed it HEAVY, so less prone to ballooning up in heat due to a weak glass job. If you're going for a light glass job maybe vent. Since you're in the PNW and it doesn't get crazy hot on the coast you might also be able to get away with no vent like I did. If you don't vent just understand that you may not want to leave it in your car for very long if it's 85 degrees out.
I used gorilla glue to glue up the blank and even with bricks in place for compression, all of my glue lines expanded quite a bit. The vertical glue lines are suuuuper annoying while shaping. Especially while pulling a screen over the rails. Clamp your glue up very tight to minimize glue expansion, or better yet just use some of your epoxy for that step and avoid the expansion problem alltogether.
One accidental benefit of the expansion problem that I had was that spaces between the foam lengths where glue had expanded unevenly allowed the deck lam and bottom lam to be connected by excess resin that dripped through my wonky blank. I'm guessing that this has helped my board to not delam. I wouldn't purposely try to do this, just adding the info for context surrounding your delam concerns. I also threw a massive 1" cedar fenceboard in as a stringer because my foam was short on width. This may have also affected resilience to delam.
Overall, I think most of us are too fearful of using XPS and if you glass carefully like you should with any epoxy job it'll go just fine.
Not sure why this is under
Not sure why this is under materials , if moved to general discussion you would get more interest .