More HD foam/skins questions. Yay!

General Discussion
1

Hey guys, I know you’re all probably sick of these but I need a little feedback. I have searched forever and found some good stuff but I’m a little unclear on some things.

My build is going to be a Mini Simmons inspired board (5’-7"). Down and dirty cheap, simple build, don’t care how it looks just how it surfs.

I plan to use the blue foam from HD for the core and glue on some poplar doorskins, and some balsa or ply rails.

I’ll cut the foam using a template from the rocker profile and cut out enough 2" thick strips of the profile to build the blank horizontally. Then glue them together with Gorilla Glue. I’m thinking all those parallel glue lines will take the place of a stringer.

Shape board and then Gorilla Glue the poplar door skins to the blank. No bagging, I guess lots of clamps/weights?

Build up the rails, nose and tail blocks with balsa. GG again? Then shape the rails.

Add one layer of 4oz. glass lam (with PE resin) to the bottom and deck to keep it all together.

I guess I need a vent too.

Can this be done without vac bagging?
Is GG the right glue for the foam, skins and rails?
Are those skins/glass strong enough with that type of core?

Any suggestions on my material selection and or methods are greatly appreciated.

2

Do you mean poplar bending ply? Door skin is not going to bend around your blank. Even with the bending ply and a vac bag I get some lift around the perimeter. My rail build ups are only 1/2" so I need the wood to bend well out to the perimeter where there are more curves.

If you do a flat deck and then create more of the rail with balsa you might get away with it.

Here is my most recent build, poplar bending ply with poplar and luan doorskin rails.

 

 

 

3

Can you elaborate on what you mean by "blue foam from Home Depot."  I thought that Home Depot only sold the pink stuff from Owens Corning.  The blue foam that I am familiar with is DOW XPS Styrofoam, and it is sold around here at Lowes.  You may want to measure the density of the foam before you start shaping it.  Just cut out a little one in cube, and put it on a digit food scale. 

Shown below is a table of the weights and corresponding densities for a one cubic inch piece of foam.  For example, if your cube weighs around 0.6 grams, then you have 2.5 pound foam.  You will probably get more accurate results if you use a piece that is bigger than just one cubic inch.  Just multiply the below numbers by the number of cubic inches in your sample.

Density and Weights for a one cubic inch sample of material:

 Density         Weight
(lbs/cu ft)       (grams)
--------------------------------
0.5                  0.131
1                     0.262
1.5                  0.394
2                     0.525
2.5                  0.656
3                     0.787

 If you are going to use XPS, then definitely read up on its pros/cons.  There is a lot of info in the archives.

http://www.google.com/search?q=XPS+site%3Aswaylocks.com&hl=en&num=10&lr=&ft=i&cr=&safe=images

 

4

I have a suggestion.....you are in New Jersey, so you have access to inexpensive, proven materials that are made specifically for building surfboards. Now, before you guys thrash me, I am all for thinking outside the box (I have foiled and glassed bamboo fins from a home store cutting board) and I like the idea of using alternative materials, but if you can save yourself some major headaches by using an eps or pu blank designed for surfboards then why not?

check out Greenlight, they are in Jersey

http://greenlightsurfsupply.com/

 

5

Marke, I planned on building out the rails maybe 1.25 -1.5. This would get rid of a lot of bending and would leave just a little crown in the deck and the bend of the rocker. I thought door skins bent easy. Should I be trying to laminate some veneer instead, then add more glass on top?

Blue, pink, white foam, whatever. That’s why I’m asking, what type of foam to use as a core. I have a Lowes and a HD nearby.

Rand, yeah I have access to that stuff, and it aint that cheap anymore. I’ve built a bunch of boards the traditional way, that’s not my goal. Seeing guys cobble together materials from a big box store, using it for things unintended and making it into a functional surfboard really interests me.

6

Hi Johnnyk3,the build you are talking about doing is not cheap after you add up the cost of your skins,the pu glue,and the foam sheet,even then your risk of failure is much higher.Get a decent blank,some E glass and some good surf epoxy.Greenlight surf supply is your best bet for materials and advice on shaping.

7

I am no expert so take what I say with a grain of salt.  I can just relay my experience with the one hardware store foam build that I have done.  I built an alaia using Lowes Blue Dow XPS styrofoam.  I am pleased with it so far, but that opinion may change if I start getting delamination problems as I use it more -- so far so good.

The Lowes where I live sells 1"x24"x8' sheets for $10 each.  Three of those sheets glued together will get your a nice Mini Simmons blank.  That's only $30 + the cost of the glue.  I used epoxy to glue them up.  I may try Gorilla glue or Sumo Glue next time.  I did a small experiment with wood glue, and it didn't work at all.  It took days for the glue to dry, and I was still able to pull the pieces apart with my fingers.

The blue Dow XPS styrofoam that I used weighed in at about 2.5 pounds per cubic foot.  That's plenty strong to be glassed on its own.  Wooden skins and rails aren't necessary.  We're going for cheap and easy... right?  I glassed it with 4 oz E glass over 6 oz on the top and bottom.  The board feels bomb proof.  I think I could have glassed it even lighter.

Here's the link to my build thread.

http://www2.swaylocks.com/forums/seal-ass-project

A couple of notes about using XPS stolen from from prior posts made by Surfding (the king of XPS).

     - Use 60 or 80 grit sandpaper only (nothing finer)

     - Sand all surfaces prior to gluing/glassing.  You want to completely remove the shiny skin.

     - You don't need to use a vent plug, since XPS is closed cell foam.

Here are some of my personal observations:

     - Surforms do not work with this foam.  They just tear it up

     - Don't cut too fast or too deep with the planer or you will get tear-out.

     - Before glassing, do a final sanding with 60 grit going from front to back in a nice even pattern.  Sanding scratches will show through the finish.

     - Prepare to use a little extra epoxy on the lamination.  The fuzzies from the 60 grit sanding job really soak it up.

Also, note that XPS is heat sensitive.  I have heard that if it is exposed to temperatures above 140 degrees, then you can expect major delaminations.  That means you can't leave it in a hot car in the summertime. 

A lot of people have tried XPS and found that it didn't work for them.  I am currently a fan, but we'll see.

 

8

Thanks guy’s I appreciate it!

I screwed up though, I’m thinking of using EPS foam not XPS. The lighter weight stuff, thats why I wanted to skin it and add the rails. I was thinking something along the lines of a HWS but without the spar and frames. The foam would be the support. Does this make sense?

9

I have done XPS and EPS with the poplar skins. Haven’t had any delams yet but it is early days. The EPS I vented with a PeteC gortex vent. Neither boards have any glass under or over the skins. This makes for a “cheap and cheerful” surfboard that is also a little more eco friendly. 

I say give it a go. Be ready for a lot of work tho’ if you decide to build up 1 1/2" with plywood on the rails.

10

When I first read the title of your post, my interest was perked…

When I mention HD foam in my posts, I’m refering to Core-Cell, Airex, or Divinicell type of "High Density " foam…

I wasn’t aware of a possible double meaning of HD… I’ll be carefull to identify what I’m talking about in the future, just to be clear…

I don’t use the blue Home Depot foam… So I won’t comment on that…

Thanks for reading…