Got some blue DOW foam from Rooster.
I plan to use 2.7mm doorskin for the stringer…
What glue should I use to glue it up?
I’ve done gorilla white or gg regular (amber) on XP, poly glue doesn’t attack it. Water-based white glue suuuuuucks unless your a gluten for time (2 days) and punishment. Many argue epoxy is the way to go, but my feeling is the foam is a lower strength than the glue itself [once cured], ergo, you probably won’t notice the difference. That said, a stringer made from door skin is pretty damn thin, maybe epoxy might beef up your application…
…come to think of it, the white gg is expensive. I just use the amber with my ply stringers and it’s looks awesome against my EPS white billets. Makes the stringer appear a little wider similar to a US.
I have a 6’-6" x30" Powerline Stringerz panel, (made from Cerex nylon). Saving my white gg for this.
so, the amber Gorilla Glue is the way to go?
I was leaning that way… does it shape easily enough when I have to plane the stringer?
Hi Chris -
It will be slightly tougher to shape but not a big deal. I've found that it is not very UV stable. It tends to turn a deeper shade of yellow after UV exposure. The clear stuff will discolor as well.
Epoxy with white pigment and microballoons is good.
I've used white pigment in polyester laminating resin on urethane foam blanks with good results but that WON'T work with styrene foam!
I use the amber GG on my XPS and EPS foam. I use lots of clamps and try to get it squeezed down real tight. On some boards, you have to look carefully to see the glue lines. XPS foam is a bit more like PU compared to EPS, you can get it real smooth if you want.
I haven’t used stringers for a while.
I usually cut my stringers to the profile I want before gluing up and shaping, then cut the foam to match the stringer profile. A doorskin stringer will be strong because it’s 3 ply. It won’t plane cleanly unless you go really slow. Same for the Blue Dow if you go slowly, it will be so smooth. Go fast and it rips up the foam.
I’ve made a few stringerless chambered blue dow with EPS boards. Blue Dow can be fussy when you glass it. Try to do the lams when the temps are falling or in an air conditioned room. Be ready to baby sit it for a while. I think some guys were saying they do an epxoy seal coat first. I haven’t done that, but I might try it when I make another board. I have about 10 slabs of blue dow right now waiting to become boards.
thanks for the tips Sharkcountry… I plan to glass the first side just as it’s starting to cool down in the early evening, the other side before 10, then finish off the 2 hotcoats before about 4 AM. Done and cured before the sun comes up if everything goes well.
John, I’m liking the epoxy/mircoballoon/white pigment option… hadn’t thought of that…
I don’t plan to have to shape the board too much. I cut it really close tolerance so, hopefully that will work for me.
Stringerless with Carbon rails!
If you go Gorilla glue, don’t forget to dampen the foam first. No moisture, no cure.
Can you add pigment to Gorilla glue?
woah, holy cow that’s a neat idea and also, “will you ever get that blank built”? I’d say coloring it is dicey. As far as poly glue yellowing, man, I’d say no way (or a loooooong time before premium epoxy like RR PH loses it’s UV absorbtion characteristics; no different than your airbrush work on the foam–nothing lasts forever.)
Get your foam really tight–a good square line and obviously less glue is needed, less janky visibility along the stringer line…and less bend in your stringer.
Stringerless is awesome too. But when you’re bending foam to wood w/XPS just glue it. XPS is a bitch to glass. I commend you for attempting.
This bad boy was done in #1.5 fused GEO 3" wired billet, 5mm utility ply (nice flex and sturdy) and amber GG in the center with light glue bead lines of white on the bottom and top of the stringer. GG only applied to the wood, and if you’re in a dry climate, yes: mist the wood and the foam parts:
Do you think chrisp and I would benefit from drilling a couple of small holes into the laminated bottom before laminating the deck to avoid out gassing? Patch them later? Mike
I had succes with regular white wood glue, no issues.
I did my last XPS using epoxy + microspheres. And I will use it again on future XPS boards.
I would not use expanding PU glue, since it will not penetrate the foam and I would fear that it would create gaps if not clamped enough. (I never tried expanding PU glue, so I can be wrong but my intuition prevents me from using it).
<a href=http://s105.photobucket.com/albums/m218/drewtang/?action=view¤t=dowfingers.jpg target=_blank><img src=http://i105.photobucket.com/albums/m218/drewtang/dowfingers.jpg border=0 alt=>
Love the stuff.
I woudn’t do that. Air does not travel trough XPS, it has closed cells.
From my experience out gassing only happens when the cells are damaged. The cells are damaged by heel dents and flexing of the foam, not while glassing.
Edit: You don’t need to patch the holes, XPS is waterproof. When I have a delam on one of my XPS boards, I push a small hole trough the glass to let it breath and to prevent it from further delams.
surfer steve did that and swears by it (but he completely perforated the blank instead of drilling 1-3 cm into each side). I never tried it. I read into the 60 grit finish method, but that produces a heavier board… more epoxy. If I was to revist XPS, I’d wrap it Cerex nylon .7oz pre-glass with an epoxy/cab-o-sill/alcohol/x-55 slurry (mixes down to a gel that wets the nylon really nicely, lighter characteristics than straight epoxy, better reach & more cost effective & faster than bagging the nylon down. Then glass it. Drilling holes into foam will make it feel dead, heavier I think. But never did try it so what do I know.
When everysurfer mentioned stringerless with carbon rails, this pic came to mind… I almost posted it. Hahaha
Not sure about drilling holes through an already laminated side. The outgassing from heat causes the glass to rise, so you may get small bubbles. That’s what you want to watch for. A razor or pin will do the trick to poke the bubble and push the glass back down flat.
I didn’t leave my foam really rough like some other have, so that may be the way to go, like 60 grit rough. I think I finished mine with 220, maybe 150.
Surfding would have a lot of experience he can pass on. Petey, the guy who used to glass for XTR in Hawaii had an airconditioned room. He’s living in Bali now.
Hi Chris,
If you do go with the carbon rails, depending on your weight, and the board’s length, it isn’t as simple as just one layer of carbon tape around the rails. I use up to three layers where I want little flex, two layers where I want some, and one layer where I want more. Stringerless with no stiffness reinforcement on longer lengths is asking for problems. Too slow coming out of turns.
Thanks Vaeske and hans. No holes. I’ll glass it during falling temperatures and babysit with a couple of cold beers. Mike
kewl…
BTW: you guys notice that Additive F is super temperamental on XPS? Maybe it was my batch at the time, but I could swear raw XPS behaves differently when compared to raw EPS during lamination. If you’re painting the blank or sealing with micros and straight epoxy then no worries, but if you’re adding Add-F into the lam on a raw XPS blank, I’m thinking strictly 1% or under Add F correct?