Three questions for board guru (yet one crazy SUP-project)

General Discussion
1

Hi, guys!

I have read all the found topics regarding building own board.

But i have yet a lot of questions. May be anyone have answers for those.

I try to explain current situation and my vision.

I want to build a SUP-board.  and I want this board have 14 feet long (may be 13.5) and 24 inches wide and ~5 inch thickness…

As example - attached file

Board not for ocean :slight_smile: , just for flat water.

Yes, I know , this is not an easy idea :slight_smile:

And, yes, i understand, that result will be not so cool as picture :slight_smile:

so…

I have review all materials allowed for order and posting in my country (Ukraine) and have build a 3d-model and have make some calculations…

And so, Question number 1:

Foam. 

Now i see only one variant with i can use for this handmade - XPS. 

Easy to buy, easy to shaping, thickness so good.

Main issue - weight - 30-35 kg/m3. This is  ~10kg (~20lbs)

not so lightweight :slight_smile:

Of course, EPS is more lightweighted solution… But I can’t find yet blocks of EPS with structure not like a “many small granules”. And these blocks (with granules) are very weakness and difficult for shaping. May be only if i use thermal knife like a “volframe string under voltage”… I’m not sure, may be anyone know solutions…

Question number 2: “with stringer” vs “stringerless”

I see many opinions for each case. but this opinions are regarding short or middle boards (i mean lenght)

Anyone have expirience with building boards more of 12 feet long?

And may be anione can help me and ansver regarding “carbon stringer” (i only hear about it, not fully understand the idea) - it is just “carbon fiber + resin” between two foam-blocks, like a wooden stringer, or something like this?

Because if i use “stringerless” case, i can save to 4-4.5kg (8-9 lbs).

And as i see, with this thickness board will less weak (i mean foam-block), So may be this concept not so bad…

Question number 3 - weight and volume of resin and glass

I don’t understand fully how to calculate - how many resin i will need (with glass all ok))). And how heavy will be the result (i mean weight of fiberglass at the end)?

…

Now i have these results of calculation:

weight of foam - 10kg (22lbs)

weight -f wooden stringer - 4kg (9lbs)

weight of fiberglass  ~8kg (17lbs) (i’m not sure)

And in this case, of course this construction will be so havy.

Thats why i find ideas how to decreese weight :slight_smile:

May be stringerless, may be little bit shortest (not 14 but 13 feet), may be little bit less wide and thickness…

May be i will add some holes to foam-block for decrease weight (not at center, but, for example in nose of board, where thickness is biggest)…

If i will have ~15-18 kg (33-40lbs) - i will happy (for me it’s enough) and project will begin  :)

…

May be this idea so crasy :slight_smile: May be questions so stupid :slight_smile: I’m ready for critics :slight_smile:

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2

Hello A64-

I have two SUP builds but they are not posted here on Swaylocks, sometimes people here are not so interested in SUP.

I use 1.5# EPS (24 kg/m^3) cut with a hot wire, then an electric planer, then sanding. XPS is a nice foam but some people have trouble with delamination after glassing.

Glassing such large boards can be difficult if working alone. A ‘wet-out table’ is a useful tool.

You will need to buy 3x and a little more the weight of mixed resin to the weight of the cloth used to finish the board. Good cloth and resin are easier to use than cheap stuff.

If you have a CAD model to make your picture, get the surface area, times by weight of cloth, and add 25% exta for lapping cloth.

You can also look at DIY kits for SUP online and see the amounts of materials and estimate from there. There are some charts online about resin usage for surfboards too.

During laminations I mix same weight in grams Part A resin as weight of cloth in grams, so mixed resin is 1.45x weight of cloth (assuming 100A (Resin):45B (Hardener) epoxy system by weight).

During fill coats it is much less but there is normally 1 fill coat and 1 finish coat.

It is easiest to mix a little short and have to mix a little more epoxy that to have too much mixed and nowhere to use it.

The numbers are just starting points, the project dictates the actual cloth and resin usage.

If you have not worked with foam, fiberglass, and resin- make something smaller first to get used to the materials…best yet buy a smaller DIY surfboard kit with instructions

Also read through some giudes like Surfersteve.com, or Greenlight Surf Supply, or Foamez, and videos from Fiberglass Hawaii

I hope it is a fun project!

PS: 14’ x 24" x 5" would be for a very skilled rider, I would sugest wider. Read more about all that on Standupzone.com

First one, stringered, crazy paint:

Second one, 36#(16kg) became stringerless during the build due to mistake and new method for ‘dugout’:

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3

for this board i would use 15kg/m3 eps core, stringerless, resin spackled sanded before lam. i would use wide carbon ud tape lenghtwise on side (rails) covered with glass top and bottom . wood sandwich all over the standing place.

4

Thanks, guys!

Your comments really usefull and important information for me.

(special thanks for jrandy for links)

But I have some reasons suspend that project.

Main problem - in Ukraine we don’t have enough warm on winter :slight_smile: and i can’t work in garage with epoxy :slight_smile: Just winter :slight_smile:

That’s why i planning delay that project. May be until spring.

I planned make at first small 7-8 ft board for my son (as test) and only then use that expirience for building “big-project” - 14 ft board (yes, jrandy, I understand it is board not for beginners))).

After delay I’m sure I post here progress of that project.