XPS Board Building Advantages vs EPS Foam

[StellaBlu]

Worth listening to a few of the podcast interviews with Weiger from Appletree.  As someone with very limited knowledge of board construction other than repairing boards (but having listened to said interviews), my understanding is that the "secret sauce" has something to do with their vacuum technique and how it bonds the skin to the XPS blank. How it differs from a normal vacuum process goes a little bit over my head, and they are somewhat opaque with the details, but I'm sure someone with more knowledge could get some hints from these interviews.

I don't think the foam differs from standard XPS.  Appletree packs all of their boards with excess foam cuttings, so if you want to inspect their foam to determine whether its normal XPS or something different, see if you can find someone receiving a board from them.  It is very dense and stiff foam.  It can carry a LOT of weight without flexing and when it fails (which is hard to do) it just snaps. 

I punctured the skin on one Appletree board, but they have clearly changed construction since then.  Another board suffered a big ding on the corner during travel, and I had to remove some of the skin and foam, which was extremely dense and well bonded to the skin.  They aren't as indestructible as others make them seem - the bigger difference is that they never seem to lose stiffness, and they don't need to be patched immediately if you do ding them.  Their new in-house tracks are also VERY solid.

[PonoBill]

I think XPS delams BECAUSE it's waterproof. EPS boards equalize the pressure of water vapor throughout the board. Water vapor in an XPS board has nowhere to go.  That's why vents work on EPS boards. They don't work on XPS boards because the air can't move around inside the board. I've vacuum-bagged XPS a lot, and while a full vacuum will crush and deform the XPS a little, it's nothing like EPS which crushes down to a wad of plastic. I've never had problems laminating onto XPS as long as the surface is prepped (coarsely sanded).

[juandesooka]

I think XPS delams BECAUSE it's waterproof. EPS boards equalize the pressure of water vapor throughout the board. Water vapor in an XPS board has nowhere to go.  That's why vents work on EPS boards. They don't work on XPS boards because the air can't move around inside the board. I've vacuum-bagged XPS a lot, and while a full vacuum will crush and deform the XPS a little, it's nothing like EPS which crushes down to a wad of plastic. I've never had problems laminating onto XPS as long as the surface is prepped (coarsely sanded).

Do you have strategies for managing this ventilation, to allow vapour to escape?

[and because no like or thanks button on this forum s/w,  thank you Stella Blue for reply too]

[PonoBill]

Probably the best strategy is don't hotcoat. In fact do the opposite--make sure any lamination is super sparse on epoxy--enough so that any trapped gas can escape through the surface. The things I've made with XPS didn't go in the water, except for a handplane.

[Hdip]

Did someone mention off cuts? 😀 new toy in case the wind ever comes back. Omen 60l which I’ll be using for winging. I’ve gotta say. Their packaging is really impressive. The foils came in a box so pretty I had to save the box.

[StellaBlu]

Did someone mention off cuts? 😀 new toy in case the wind ever comes back. Omen 60l which I’ll be using for winging. I’ve gotta say. Their packaging is really impressive. The foils came in a box so pretty I had to save the box.

Dying to hear how you like that Flux.  Im considering the 48L to replace my daily driver (Apple Slice v2 60L).

Re: the cuttings - those cuttings (green) are different than all my other Appletree cuttings (white).  Also, all of the Appletree boards I have recieved from the factory (including this year) are packaged in the full cuttings from the blank in a single piece (board nestles right into the donut hole from the rectangular blank).  Point being - Im not totally sure whether those cuttings are from the blank or not.  Maybe they are doing something different for the Omen boards.  Im sure your packaging was lighter to ship than what I've had in the past.

[Hdip]

Interesting. I have the 4'3" 36L and really like it. I've come off of 4'5" and 4'6"s in the 27-31L range. The Omen 36L feels longer than any of the other boards somehow, but does a better snap turn than my older boards, and can hold on a rail turn when needed.

Very excited to get the wing board in the water. Which of course means there's no wind anywhere in the forecast.

[surfcowboy]

Pono called it. Delams are caused by the skin blowing up like a balloon. Carbon when bagged and filled lightly, which means about as good as any home guy can do is full of pinholes. That's should vent you fine. And if you laminate anything with a bag and the blank is coarse sanded it'll be stuck down well so not much water will get in and since the foam doesn't absorb it'll just dry when you get out.

Clay and Beasho are showing a new and likely better way to make foil boards. I've maintained for 2+ years now that these are not surfboards. They are tools for getting on foil. We gotta stop trying to polish them like a longboard and we need to ignore all the surf dogma and make what works.

Go build one. I'm trying to work out sourcing XPS myself.

[PonoBill]

Home Depot XPS is just fine. In fact, the quality is better than some of the "surfboard" XPS I bought. I think it's challenging to make XPS that is homogeneous. Some of the stuff I played with had areas that probably didn't foam well and had the consistency (and weight) of PVC. the pink insulation is perfectly homogenous. The only problem is that it's scored to break. Some folks break it and glue it back together with good foam glue (regular Gorilla Glue is NOT Da Kine. The clear non-foaming GG is better, but specialty foam welding stuff is WAY better). But really, once it's laminated, the scoring doesn't matter. I just use it as is. I'm getting ready to buy a silly quantity because I want to build an ultra-light trailer for my dirt bikes (yea! another project), and I'm going to use XPS to make a streamlined body. Towing behind a Tesla has special requirements. I've been fiddling and I have my ordinary modified trailer tuned up so it only cuts mileage by 20 percent. I'm aiming for nada.

[surfcowboy]

Pono, I wished we lived closer together. I literally have a YouTube feed filled with foam walled camper trailers.

Good to know about the Home Depot foam. It was constrained here for a bit but I saw the 2" thick back at some locations. Just gotta look around. Also a good tip about the other foam glue. I have some good prop house supply places near here and they have tons of that kind of stuff. Didn't know it was superior. Thx.

[seastudent]

Also you can get 3" thick at home depot. I'm fiddling around with a board at 7'6'' x 22" and got it out of 1 sheet.
 Bill, could you give some guidance on rough sanding? I kind of smoothed mine out to 120 grit to help my eye and hands find my many, many flaws. I can certainly roughen it back up.

[PonoBill]

I do a once-over with 40 grit. Very light pressure--you just need to scratch it up

[clay]

My boards are diy builds.  We had Jeff's 2 year old prototype as the model for what might work, and then Denton got all scientific and did tests and came up with a glassing schedule.  So we ran with that and our own best guesses.
I made a full tutorial of my wing board build:
https://clayisland.com/how-to-make-a-waterproof-wing-foil-board-video-tutorial-from-start-to-finish/

[clay]

short version:

[juandesooka]

anyone experimented or heard anything boarding shaping using graphite polystyrene (GPS) foam?
https://www.progressivefoam.com/eps-vs-xps-vs-gps/

Is it more like EPS or XPS? Appears to  have more moisture retention, which is bad (when board inevitably gets dinged) and maybe slightly good (perhaps improves on the resin absorption / delam issues with xps).

Apparently this is the most common rigid insulation in Europe. I am curious if this may be related to Appletree's proprietary closed cell foam.

This all flows from my looking for 4" thick sheets of xps, unsuccessfully so far -- shows they make them, but out of stock.  A friend in the green home biz recommended checking out gps.