Newbie with first 3 paddleboard build questions. Material, Layers, Skin/coating

I know it is long, but I wanted to put it all together for context and because the questions are interrelated. 

 

Background: Newbie here, and I’m looking to build a folding or 2 part paddleboard so it will fit in the car/van but still have an 11-12’ board with 32" beam. It will probably be a displacement design as it’s all lakes in my home of colorado, but I might still do traditional design so I can use it when we do drive to TX or CA for beach weeks. I’m big (>200), so need a big/sturdy board and ideally could use it with the dear wife (DW) for sit on kayaking. It will probably only see 100-300 hs of water time a year and will be garage kept.  

I’ve read a ton here and other places as well and plan to eventually post my build here (and probably Instructables). I’ve never built a board or boat but and good at building things. However I hate epoxy/fiberglass and react badly enough to it I’ll probably avoid it if I can avoid it even it impacts my design choices. Since I’ve never built a boat/board (and have an inflatable), my DW is not really on board, so I need to do it cheap for now to prove the idea. (I’m an inventor with many patents and think my design could be patented but will likely post full plans online even if I file a patent so DIYs can do it themselves). 

 

Here are my 3 first sets of design questions

  1. Materials

My first group of question is materials. My real preference is to get stuff on its way to the landfill or well used, but that has been very limited in choices so far.  

1.1) I know I could do a stitch/glue plywood, but locally I cannot get 4mm or 5mm marine. I can get 1/4 underlayment, but then it’s going to be heavy (~60lb of wood + PMF coating ). I’ve got 1x4 furring and 3/8 exterior ply I can use for stringers/folding connections on any of the builds. I know I could make this design work and build that all in for < $80. 

The rest of the materials are foam. If I go any foam route, I’ll probably have a plywood standing platform, so I only need enough strength or the occasional misstep and crashes. 

1.2) Locally, I can find polyisocyanurate foam used for cheap ($10 for 3 1"x4’x8’ sheets or $15 for 3" 4x8 sheets), and with that, I can use low-cost Polyester resin such as Boatyard resin which is $14/gallon  (CORRECTION:  Its $40 a gallon). https://www.bottompaintstore.com/Boatyard-Polyester-Resin-Gallon?gclid=CjwKCAjwjJmIBhA4EiwAQdCbxurdI2dQ35j_pd2Z75THlp866_4OH1L9suTLMmAJAycFbeyisgRAsRoCBmUQAvD_BwE. I’ve read most of the thread here that mention that type of foam, and it does not seem to be well respected. It is also pretty heavy (3" 4x8 is like 30lb before any glassing work). Also not sure how well it will handle building a hinge connection with the weight. So I have that way down on my list, but if anyone has positive experiences to report, I might reconsider because I can use polyester resin which, while not as good as epoxy, is better than PMF and the total cost for a higher-end finish is still reasonable. 

1.3 I can keep looking for XPS or EPS scraps (or give up and buy XPS sheets for about $70 or EPS for $50). There are choices of compression strength (25psi 15psi 10psi), and I could not find good threads on the tradeoffs. To support the folding/hinge, I will have two 3/8" plywood stringers so I am curious how the PSI /rigidity trades off with two singers. (2 would be 24" apart to be under my feet). Since either is lighter than either plywood or poly iso, I like these choices  a bit more, But since I hate epoxy and polyester will melt it(unless I add coating), I am tempted to do PMF (more below) on it and am not sure if it will then be strong enough for my mass, specially lower density EPS.   Any comments on strength/density needed? 

1.4 The crazy idea – I have dozens of sheets of 3/8" white form core board (paper on both sides of foam use for academic projects) and think I could build a board for the cost of glue. To test it I build a small grid of knock-down interlocking 4" strips separated by about 4" horizontally and vertically. With that I put a 3/8" foam board piece on top and stood on it. The paper cracked and dented under my 200+ lb on one foot, but it did not break. Then added a coating of 6mil polyester fabric + titebond glue and let it dry overnight. I could then stand on that piece without any cracking. I can make a denser grid, maybe 2" or 3" spacing, and then add 2 layers on the top with layers of fabric/glue between each. (I’ll use to glue to waterproof the paper layers as well) and then coat with PMF and use a plywood standing board. I’ve not estimated total weight, but the sheets are light, and since the major of the volume is air in the grid, I think it might be lighter than XPS. Does anyone think this is just too crazy to try? Or crazy enough to keep exploring. 

  1. Layers 

2.1 For either foam choice, I’ll need layers. Some ISO sheets have foil; some have glass mats. I’m wondering if adding glue or polyresin to those glass mat facings would make up for the fragility of the ISO sheets (though it will add weight).  

2.2 Similarly, for XPS, everyone seems to glue the foam to foam. I was wondering if adding a layer of fabric+glue between the two layers would provide added strength? I have a lot of free polyester poster fabric that is very strong (I can hang my 200lb from a 1" strip of it uncoated). If I do, would titebond or gorilla glue or foam be better between the sheets/fabric lamination?

2.3 If using PVA glue (titebond) and doing layers to avoid delamination, is it best to let it set but not cure and then add the next layer or let it cure, sand a bit, then add next layer? 

  1. Skin/Covering:

3.1 I am leading to PMF – titebond II over the fabric. Most people use canvas or bed sheets (canvas) or fiberglass. But I’ve also seen various posts say it is important for strengths that the glue be absorbed by the material, but glass is not absorbing, just filling the gaps. So I thought the polyester fabric poster material I have would be sufficient/good since it will not mold if wet. Any comments on that?

3.2 My second choice is the Boatyard polyester resin which will make a nicer /stronger finish (but cost 2x). This is an unknown formulation for $40/gallon – does anyone have experience/comments on it.  

3.3 A more traditional poly resin would be $60 and epoxy $80-150 + glass. I know resins are both stronger, but I can do PMF for the whole board for <$20). Given my very limited use per year and uncertainty about the folding design, I’ve also wondered if the PMF would also help highlight any design flaws with less testing than the stronger resin-based covering. Does anyone with experience want to comment on that? 

 

Terry

I’d give this up and just buy a cheapo at Costco or Bru.  Add a set of roof racks to your car and call it good.  The negatives for you far outweigh the positives.   #1 You have never built a board of any kind previously.  #2  You have outlined a unnecessarily complicated build process and littered the process with multiple “What ifs?” and monkey wrenches.  But more importantly you have stated that you hate resin and fiberglass and react badly to it.  I wouldn’t attempt this if I were you(and I am not).    Got a desire to build something?  Build a nice book case out of reclaimed lumber.  It will be a fun experience cruising the back roads looking for old barns.

PS—   Your coast estimates are completely 1950’s .   “All in for $80”. ??    Come on.

Thanks for your thoughts on how I should proceed.   The positives for me are learning and exploring new ideas… I cannot lose on that front.   Luckily I am not easily discouraged.

 

Nope, I’m not that old. It is the current local pricing.  The $80 for the wood +recycle build it is based on

  • 2 4x8 sheets 1/4" underlayment exterior rated plywood @21 each from Lowes  (If I cannot find crates to recycle.. I already have 1 but its 3/8" plywood). 
  • 1 gallon Titebond2  for both joining and PMF $18 from Lowes
  • Stainless Hinge  $9  (though  already have ones left from another project they are bigger than I'd want to use)

The total above is  <$80 including tax and that is if I cannot find the right plywood to recycle.  

 

The rest of the material is recycled and already in the garage from other projects. 

      ~24 yards of Material for PMF and tape/glue strips  Free (recycled old posters with strong woven polyester material.  )

     ~16ft of  Furring strips for framing support and hinge joint board   Free (recycled from Crates/Palets) It would be $25 if I had to buy them. 

     Exterior paint (various colors free from discards @ local hazardous waste recycling center where people drop off unused paint that cannot be thrown in the trash). 

 

This ought to be good.

 

Amigo, I fear this project is beyond your grasp.  And your budget.   

The conventional wisdom with board building is that your first dozen or so boards are the most expensive boards you’ll ever buy.   That’s because your costs aren’t just limited to core, skin and finish.  It also includes all the tools and the consumables it takes to get to the end of that process.  Not to mention the value of your time compared to if you used that time to work some extra hours at your day job.   Heck, just a good set of fins is going to cost $100 or more, and that doesn’t include the fin system and install kit that it takes to get the fins on the board.   

You’d come out ahead if you took a temp job at the grocery store for a couple weeks and used the proceeds to buy a finished board off the rack - that will take fewer hours than what it will take you to build your own.   It takes time and effort just to source all your materials, consumables and tools.    

My advice is to not even get into building boards unless you are going to stick with it and build at least a dozen of them.     And then if you do go forward, you should plan to start at the beginning with a clean, simple design and process.  No extras and no quirks.   It takes a lot of thought, plannning, care and effort just to get to a clean outcome with a “basic” design.   

 

It’s an SUP? Should I even comment?

Wow …  very tough crowd…   not at all like the dozens and dozens of helpful threads I’ve read on swaylocks before posting.  Maybe my detailed message sent the wrong tone, or that the DIY spirit left here years ago and I should head over to boatdesign.net or reddit. 

Thanks for the idea of working at a grocery,  but financially I’m well off and don’t have to work at all.    It is not about what I can afford to buy, it is about what I want to do, want to learn and want to share/teach.   It is fun to learn new things, and I wanted to explore some novel design ideas using as much recycled material as I can.  My focus is functionality,  not “a clean outcome”. 

Fins are trivial to build,  with literally dozens of threads here and videos on how to do it with plywood and even some with plastic.  Easier than building airplane wings, which I’ve done before.   Hand foiling super-efficient wings/fins may take some effort to match a proper shape, though for fins they are also easily 3D printed). However, for a SUP  precise shape is not that critical  – it could be a pretty much flat skeg/keel.  The hardest thing is attaching them, but plenty of threads here on that too.      Admittedly most plywoods fins are glassed, and boxes glassed-in,  but there are many other choices for attaching as well. Fins are easy, which is why I did not even ask about them 

"However I hate epoxy/fiberglass and react badly enough to it I’ll probably avoid it " 

I started reading with great interest until I came to this…  What you are brainstorming is indeed more complicated than it needs to be but the basic waterproofing/surface reinforcement aspect of it is going to be tough.  I suppose with enough adhesive, varnish, veneer. and maybe a vacuum bag setup you could finish a sealed wood covered shape.

I personally believe (and I’ve made some big boards) that a board at the size you suggest will be approaching some extreme weights unless you stick with light density EPS and some epoxy/fiberglass reinforcement. If epoxy is definitely out but if polyester can be used, USBlanks has a new polyurethane foam blank that I don’t think is even in the catalog yet… at least I haven’t seen one that had it.  On their blog I caught wind of a new 12’3" blank that could be fairly easily shaped (somewhat pre-shaped) and glassed with polyester resin/fiberglass. 

At some point a board that is too heavy (“too heavy” = a subjective term, I realize) will be a bitch to get in and out of the garage or backyard and unless you drive nearly to the water, it’ll also be a bitch to carry to/from the car.

Just speaking from my own experience, not trying to disuade you from the overall project. Think smart, keep it simple and definitely consider the final weight.

I always discourage new builders from going off the deep end and including too many experiments in their first few boards .  Always.   I always tell new builders to use a simple design and to focus on the craftsmanship angle above all else. To not even think about doing airbrushes or resin tints/opaques because they just add more drama to the build.      Your proposal goes way beyond adding color to a conventional build. 

Shape comes first, and that’s a huge element of board building to learn all by itself.  If you want the board to function then you need to start off with a good idea of which features do what. 

Just as one example of the problems you’re adding to this project is that you’re  starting off with a slab instead of a rockered and foiled blank.   That means you are already going to face the challenge of building rocker and foil into your blank, which for a new shaper that’s way easier said than done.   Getting that curve right is just part of the challenge; getting it clean AND symetrical relative to the blank thickness is going to be all-but-impossible for most new builders.   

Another example is that you seem to think fins are so easy that you already understand fins, so you can just bypass that question altogether.  Lemme tell you, the idea that “fins are easy” is going to come as news to just about everyone here.  IRL, figuring out exactly what you’re going to do with fins is a critical part of the design process.   

The point is that you would get a much more caring, sensitive and nurturing response here if you start off with a more modest proposal.  I don’t say that to be mean, but to prompt you to a more doable project.  We want you to succeed and get the outcome that will lead you to build more boards and develop more skills.   As opposed to getting in over your head and quitting altogether halfway through because it’s hopeless.   

Just go for it.  What do I know?  Just be sure to post a build thread and pics.  Like the guy who was gonna make blanks out of Two-Part Pour Foam.

Naw.  We’re not tough, just realistic and fact based.

Sounds about as unfunctional as anything I have ever heard of.  But I don’t want to chase you over to a boat design.com or Reddit;  so by all means, proceed, post and take pics.  Place has been a little boring of late anyway.   Welcome to Swaylocks.  Glad you came along when you did.  If myself, GDaddy, BillT or sammyA didn’t update a few threads every couple of days, the place would dry up and blow away.   While I am at it;  Somebody post something new For Sale on Surf Shop.  Don’t become a bunch of house bound hoarders.  Lowel

You’ve received good advice here, which is what you were looking for.  If you build it, and I advise not to, I wish you well and hope that you will report back with pictures and weight.

BTW, the great and encouraging advice most newbies get here is because they are building foam boards, often from real surfboard blanks.  

All the best

[quote=“$1”]

I know it is long, but I wanted to put it all together for context and because the questions are interrelated. 

Ohhhhkaaay, a few things, Be forewarned that. like the Pirahna Brothers, I use sarcasm. And if you thought yours was long… Gah - here goes my evening. 

Background: Newbie here, and I’m looking to build a folding or 2 part paddleboard so it will fit in the car/van but still have an 11-12’ board with 32" beam. It will probably be a displacement design as it’s all lakes in my home of colorado, but I might still do traditional design so I can use it when we do drive to TX or CA for beach weeks. I’m big (>200), so need a big/sturdy board and ideally could use it with the dear wife (DW) for sit on kayaking. It will probably only see 100-300 hs of water time a year and will be garage kept.  

Background - pretty much everything you describe has been tried one by one…with at best limited success. Attempting to do them all together is a nightmare waiting to happen. 

Let’s start with the folding aspect. You’re talking about a hilariously long and wide thing, with a lot of area. The static loads alone are gonna require a REALLY STRONG system to hold it together, and then you have dynamic loads, like waves and wakes and chop and so on. Okay, neat, you come up with something, carbon fiber, titanium, whatever, you still need a really rugged substructure to fasten it to, tied into the rest of the board and real rigid. Which will be at the very least heavy, plus expensive.  People have been trying to come up with a working folding board for at least forty years that I know of.  Note I say trying. Not succeeding

As has been suggested, and I will note kindly suggested, get a roof rack. Lose the folding idea.      

I’ve read a ton here and other places as well and plan to eventually post my build here (and probably Instructables). I’ve never built a board or boat but and good at building things. However I hate epoxy/fiberglass and react badly enough to it I’ll probably avoid it if I can avoid it even it impacts my design choices. Since I’ve never built a boat/board (and have an inflatable), my DW is not really on board, so I need to do it cheap for now to prove the idea. (I’m an inventor with many patents and think my design could be patented but will likely post full plans online even if I file a patent so DIYs can do it themselves). 

Uh huh. Don’t enumerate your mature poultry as ovae…

 

Here are my 3 first sets of design questions

  1. Materials

My first group of question is materials. My real preference is to get stuff on its way to the landfill or well used, but that has been very limited in choices so far.  

1.1) I know I could do a stitch/glue plywood, but locally I cannot get 4mm or 5mm marine. I can get 1/4 underlayment, but then it’s going to be heavy (~60lb of wood + PMF coating ). I’ve got 1x4 furring and 3/8 exterior ply I can use for stringers/folding connections on any of the builds. I know I could make this design work and build that all in for < $80. 

 

Awright, lauan is cheaper and lighter than underlayment. Stitch and glue is overrated, speaking as a guy who does build boats. It’s also heavy and expensive, what with the fillets of resin plus filler in every join and seam. There have been a lot of very successful hollow wooden boards built, the tech and instructions are out there, interior bulkheads and formers made of ply and such, reinforced with wood. Not a bad way to go. Requires very good woodworking skills and tooling.

 

The rest of the materials are foam. If I go any foam route, I’ll probably have a plywood standing platform, so I only need enough strength or the occasional misstep and crashes. 

Bzzzzzt- wrong answer. 

Just to start with, putting a single-point 100kg load in the middle of something that long is gonna make for considerable stress. And that’s just the static load. Dynamic loads, like waves breaking on it or even when you have the nose and tail supported (say, paddling across a boat wake) and the center ( with you on it) unsupported- Ungood. 

 

1.2) Locally, I can find polyisocyanurate foam used for cheap ($10 for 3 1"x4’x8’ sheets or $15 for 3" 4x8 sheets), and with that, I can use low-cost Polyester resin such as Boatyard resin which is $14/gallon. https://www.bottompaintstore.com/Boatyard-Polyester-Resin-Gallon?gclid=C…. I’ve read most of the thread here that mention that type of foam, and it does not seem to be well respected. It is also pretty heavy (3" 4x8 is like 30lb before any glassing work). Also not sure how well it will handle building a hinge connection with the weight. So I have that way down on my list, but if anyone has positive experiences to report, I might reconsider because I can use polyester resin which, while not as good as epoxy, is better than PMF and the total cost for a higher-end finish is still reasonable. 

The Iso foam isn’t bad for some things. I’ve built boat stuff, insulated fish holds and so on from it. Typically it’s foil surfaced and glass won’t stick to it. Works fine with polyester resin just fine. Problems include how much foam comes away with the foil when you rip it off the sheet. And how you’re gonna deal with that. 

1.3 I can keep looking for XPS or EPS scraps (or give up and buy XPS sheets for about $70 or EPS for $50). There are choices of compression strength (25psi 15psi 10psi), and I could not find good threads on the tradeoffs. To support the folding/hinge, I will have two 3/8" plywood stringers so I am curious how the PSI /rigidity trades off with two singers. (2 would be 24" apart to be under my feet). Since either is lighter than either plywood or poly iso, I like these choices  a bit more, But since I hate epoxy and polyester will melt it(unless I add coating), I am tempted to do PMF (more below) on it and am not sure if it will then be strong enough for my mass, specially lower density EPS.   Any comments on strength/density needed? 

Awright, gluing stuff together, scraps and what have you - but what are you gonna do to stick this jigsaw together? Also, adding a coating, yeah, that’s nice, but just how well is the coating sticking to the foam? How well will the resin stick to the coating? Will it fail in shear under stress? Glue as a barrier coat has been used for polyester ding repairs on styrene foam boards, which are really small and structurally tied in to the rest of the glass. It used to be hard to get decent epoxy for repairs, which is why we did it. 

1.4 The crazy idea – I have dozens of sheets of 3/8" white form core board (paper on both sides of foam use for academic projects) and think I could build a board for the cost of glue. To test it I build a small grid of knock-down interlocking 4" strips separated by about 4" horizontally and vertically. With that I put a 3/8" foam board piece on top and stood on it. The paper cracked and dented under my 200+ lb on one foot, but it did not break. Then added a coating of 6mil polyester fabric + titebond glue and let it dry overnight. I could then stand on that piece without any cracking. I can make a denser grid, maybe 2" or 3" spacing, and then add 2 layers on the top with layers of fabric/glue between each. (I’ll use to glue to waterproof the paper layers as well) and then coat with PMF and use a plywood standing board. I’ve not estimated total weight, but the sheets are light, and since the major of the volume is air in the grid, I think it might be lighter than XPS. Does anyone think this is just too crazy to try? Or crazy enough to keep exploring. 

Heh, I am not gonna discuss single crazy ideas. - look, I’m glad you did a test. But… you didn’t do the right test. You simply made your sandwich and set it on the floor and stood on it to see if it would squish. Yeah, that’s nice- if you are gonna use it only on solid surfaces. 

Now, make up a version of your sandwich, say eight feet long. Put it on a couple of  sawhorses seven feet apart and then try standing on it. I’d maybe put a mattress on the floor first. 

Okay, if you wanted to, you could probably make a very nice hollow board with this 3/8 stuff, similar construction to the hollow wooden boards. You will need to reinforce ( glass or carbon fiber) every piece. And glass them into position. This becomes…interesting. 

 

  1. Layers 

2.1 For either foam choice, I’ll need layers. Some ISO sheets have foil; some have glass mats. I’m wondering if adding glue or polyresin to those glass mat facings would make up for the fragility of the ISO sheets (though it will add weight).  

The foil is to help with R-rating. The glass mat is so you can resin the stuff ( say to make a boat deck) and add another layer or several of mat for strength and abrasion resistance. 

 

2.2 Similarly, for XPS, everyone seems to glue the foam to foam. I was wondering if adding a layer of fabric+glue between the two layers would provide added strength? I have a lot of free polyester poster fabric that is very strong (I can hang my 200lb from a 1" strip of it uncoated). If I do, would titebond or gorilla glue or foam be better between the sheets/fabric lamination?

Awright, to begin with- cloth between foam layers will add some stiffness. They used something similar with cold-molded boat construction and Really Good Glue for PT boats back when. But that’s not the issue. This will be, as surfboards are, a monocoque structure, the strength is in the skin. 

Now, I’m real glad you have all this free polyester fabric. I’m sure it has an ultimate strength that will hold you. But it will stretch before that, which in turn will make for some very interesting things going on as the board flexes and shear happens. Make yourself a sail or some pants or something. Fibrrglass and carbon and for that matter Kevlar stretch little if at all. Which is why they are the laminating fabric of choice. 

 

2.3 If using PVA glue (titebond) and doing layers to avoid delamination, is it best to let it set but not cure and then add the next layer or let it cure, sand a bit, then add next layer? 

Personally, I would glue, place, glue, place until you have it completely layered, then weight the living phuque out of it, use a roller to get air bubbles out of it first of course. But again, I wouldn’t do this in the first place unless you are effectively making a 3" plus thick blank out of it and even then…

  1. Skin/Covering:

3.1 I am leading to PMF – titebond II over the fabric. Most people use canvas or bed sheets (canvas) or fiberglass. But I’ve also seen various posts say it is important for strengths that the glue be absorbed by the material, but glass is not absorbing, just filling the gaps. So I thought the polyester fabric poster material I have would be sufficient/good since it will not mold if wet. Any comments on that?

 

Yeah, comments above. Look, back when there were some very cheap department/dollar store import boards that were fabric covered foam. As boogie boards they wrked badly, as surfboards they most definitely snapped like breadsticks. 

Resin permeates the weave of the glass cloth, not the fibers. Neat. And irrelevant… Our British friends refer to boats built of resin and fiberglass as GRP, Glass Reinforced Plastic, which is a helluva sight more accurate than what we call them, ‘fiberglass’ . And the strength is in the skin. 

Fabric over all- yeah, well, it might keep water out until it wears or gets cut. Strength, no. In boat work they used to do canvas or muslin (sheeting) set in adhesive over thin planked lightweight decks where abrasion and impact didn’t figure into it. Used to, now they are typically glassed. With…

 

3.2 My second choice is the Boatyard polyester resin which will make a nicer /stronger finish (but cost 2x). This is an unknown formulation for $40/gallon – does anyone have experience/comments on it.  

It’s not a bad product…for boats. Typically it’s an inexpensive waxed sandable resin which means if you are doing multiple layers you need to do them all at once, which gets kinda messy. Or else grind and grind and grind.  It’s quite good with mat or woven roving, heavy heavy stuff, not so great with cloth. . 

 

3.3 A more traditional poly resin would be $60 and epoxy $80-150 + glass. I know resins are both stronger, but I can do PMF for the whole board for <$20). Given my very limited use per year and uncertainty about the folding design, I’ve also wondered if the PMF would also help highlight any design flaws with less testing than the stronger resin-based covering. Does anyone with experience want to comment on that? 

Terry

Yeah, well, a few suggestions. 

I remember reading a history of a particular aircraft where it was noted that the minor flaws were such that they completely hid the major flaws. When testing, you want to change one variable, not a bunch of them, lest you find that you have no idea what went right or wrong in the overall train wreck. 

Look, I applaud your desire to reuse and recycle materials. The surf biz is amazingly wasteful, just to start with. But that is a major project in itself. 

Then there is the radically different structure you want to try, construction, materials and so on. Oh, and making it folding.

As the cliche goes, how do you eat an elephant? One bite at a time.  

The methods now used in surfboard construction came about very gradually, trial and many errors. A lot of them failed. Probably including much of what you want to try all at once. 

So maybe you want to at this gradually, one thing at a time. Or, opon reflection, you may decide that the time and expense in the several (many) iterations to get any one of these things right are not worth it and buying something off the rack is a better use of that time and money.  

hope that’s of use

doc …

Obviously you have not bought any plywood in quite some time.  OSB sheathing usually $12 a 4x8 sheet was $42 per sheet when last I checked( which was about 2 weeks ago).  You won’t but anything with Exterior glue for $21.

Dr_innovation, you get here lot of view of long time boards builder, may be not what you want to read because seems you already have yours. I’m french I don’t understand exactly what you want to do but seems you say you have time, money and knowledge so let’s go embody you avatar “Dr_innovation”, after all that’s how all invention are born.

For model airplane we sometimes use pu glue with or without fiber between eps foam and wood instead of epoxy with success. Some used it here for boards with success too.

If you are ‘financially well off and don’t have to work at all’;  Why such a cheapskate?  You getting that extra $600 a week from Joe?  You’re a great example of people with too much time on there hands.  But please head on.  It will be a fun read.  Doc has given you some good vibes, so pay heed.

Pay close attention to Doc’s advice and read multiple times to absorb.  Please proceed and keep us advised.

I went to your link at Boatyard and the resin you describe is actually $39.98 per gallon.  And if that pricing hasn’t been updated lately probably more $$$.  So where is the $14 p/gallon stuff.  I want to order a drum.