Im going to post this to see if anyone thought of this before. I had two ideas before about making a board out of cheap materials .
Make a mold , fill it with that canned yellow foam insulation that you buy at home depot, and it swells up . Then shape it and mold a fiberglass shell over it.
I noticed last month on a construction site, they had 2 inch thick styrofoam 4 ft by 8 ft sheets. Would it work if you glued 3 together off set the seams so you end up with a 12 ft by 4 foot by 4 inch thick styrofoam blank . with the seams offset. youd have to get ribs or make ribs then glue all that together. And also why does everyone carve the shape into flat blanks instead of bowing them up to match ribs shape.
Many attempts have been made at blowing your own foam blanks. Many fledgling companies have tried it as well. To make a decent structural foam with consistent density is a difficult process. If you decide to try anyway, consider using a 2-part ‘pour foam’ rather than the insulation stuff from an aerosol can.
Gluing styrofoam panels together is a much better possibility and has been done successfully by some people here on Swaylocks and elsewhere.
Assuming you are contemplating doing your own surfboard(?) I would humbly suggest that you make it easy on yourself and purchase surfboard specific materials from a legit surfboard material supply house. The blanks are ready to shape (practically pre-shaped) and the glassing materials are surfboard friendly. At least they’re more friendly than trying to piece meal something together using construction grade stuff from the hardware store. It can be done but you will stand a much better chance of success (and that’s not a given) using the right stuff.
In this day and age, there is really no point in trying to reinvent the wheel.
PS - Have a look at Sharkcountry’s thread on the Franken Board. Keep in mind that he and his brother Bernie have made dozens of boards by hand and have tried nearly every conceivable method. With a good eye for shaping and dedication, you can make a board out of many materials. Sharkcountry is a perfect example of a guy who can do it.
A lot of us have been trough this especially in the days when it was much harder to get a blank. Research older threads on doing your own foam/blanks. Or, take it from Mr. Mellor and realize it isn’t worth it overall. A professional close tolerant blank is the way to go. Doing “Frankenblanks” a la Sharkcountry is a fun challenge but we are talking master craftsmen here with either traditional or found materials. It will be a long experiment in finding square one again.
Not master craftsman, just a hack having fun doing things the hard way. If my brother and I didn’t learn how to make Balsa skinned composite sandwich boards, we would never have experimented with alternative foam. The first boards we made used regular surfboard blanks, but they ended up heavier with the balsa skins.
If you have a real good vision of what you want to make, the materials shouldn’t be a problem. The problem will be the materials will not be as good as the stuff that has been developed over time and is designed to make it building surfboards very easy.
I’ve worked with flat sheets of foam as thin as 1 inch, and blocks 8’ x 4’ x 6". I’m using a block that was 4’ x 4’ x 13" now. I cut rocker strips and glue them together to make the length and width I want. You need to be mindful that each glue line you cut through will give you issues trying to make a perfect curve. Sometimes, you can be fighting that hard spot and it will drive you crazy. Get angry and rush, and you will mess up.
If I was to use 8’ long foam to make a 12’ long board I would stagger the lengths of foam so that each joint is against a solid piece, so 8’ and 4’ on one then 4’ and 8’ for the next one. The reason I prefer rocker slices to gluing up flat pieces to get the thickness, I have a really hard time making a smooth curve when you hit that glue line. EPS tends to tear and the glue line stays proud.
To avoid that I cut the outline narrower and add a piece of foam around the perimeter of the board to get a clean rail. Otherwise those glue lines have to be dealt with. Not a problem if you just have 1 or 2, but gluing up 2" thick foam will have quite a few strips. EPS and XPS foam require epoxy resin, and where I live epoxy costs more. But I bought a lot of foam real cheap years ago, and I’m still trying to use it all up. Once I’m done with it, I have almost a dozen real blanks to use. I use those now when I want a good board because it’s a lot easier to do.
Here’s a couple of shots of rocker strips from 3" thick XPS foam. I think 6" is the best for rocker strips. Cut 4, then cut the 4th into thinner pieces for the outer rail band.
Have you ever thought about wood? It can be a construction material too and it can be cheap. My latest project (see 4pc collapsible) is a hollow wooden construction filled with a light higly expandable and low water absorbant can foam. Don’t build a mould but build a HWS and stuff it. A little warning, I could not test the board by now, but I do not expect severe problems, if they will occur, then not in the wood/foam construction but in my collapsible feature, but you do not habe to build a collapsible. Read a little about wooden boards (www.woodboardforum.com) build a frame, plank it, foam it, build the rails. Depending on wood used, you may not even need epoxy. Look at Mr. Wegeners compsand board, he planks eps with paulownia it is another way of building and needs a blank, but finally its a wooden hull filled with foam, her eps as a start, my proposal is starting with the wood and fill with foam. You do not need to shape foam, eps, which is quite a mess. The outspilling can foam builds up and you just cut it away with a knife…
Using the can foam, you can build very light, use a wide rib distance, use thin panels, less glass and epoxy.
Sharkcountry, you are a master craftsman because you know your numbers, what they really mean, and use of “oddball” materials and methods. You can turn out a viable ride with all these different boards. THAT is pretty masterful in my book.
Our first few boards were ‘construction’ grade lightweight EPS with milled SPF stringers, local cloth, and a low-VOC poly tooling resin that looked like pancake syrup.
They were about as ugly as sin- both in design and execution.
On the next batch I adopted heavier EPS, surfboard cloth and epoxy (mail order), plywood stringers.
I still struggle with design and cosmetics but the quality of the material set is no longer a major issue. Better materials are indeed easier to use.
If there were do-overs I would have just ordered a couple DIY surfboard kits with the fixings and go from there instead of going broke saving a nickel.
If at all possible, starting with one of these kinds of blanks is way better. The slab was made by our local EPS foam manufacturer. They supply our Home Depot with the 2’ x 4’ or 4’ x 8’ sheets in 1", 1.5" and 2". They started making the surfboard blanks after Clark Foam closed, and had a bunch in stock, but now you have to order them. Several of my friends bought the inventory available when they decided to clear out their warehouse.
I lucked out and scored 2 Marko blanks off of Craigslist. My brother and I used them when they first started making the molded EPS. They have done a lot of work making the molded blanks very good.
