Question for Noodle about epoxy

You’re going to screw something up on your first board no matter what > materials you use. Mike & Noodle - I wish I could say my first board was the last one I screwed up.

P.V.- E-mail me off one of my board postings and I’ll hook you up with a friend who builds boards up near Lake Conroe. He’ll let you come over and watch him work I’m sure. TS

I’ve only now heard of “cheatering”. The rep at Daka Epoxy told > me something about epoxy that turns out to be true. He said that epoxy > resin is an excellent bonding agent for all surfaces except hardened > epoxy. He said that all agents, including epoxy, bond poorly to hardened > epoxy. I can’t see why you would want to prime a blank with a substance > which resists being bonded to. You would have to sand the epoxy to make it > accept the next agent, but sanding would probably remove all of the > “cheatering” layer if it is so thin. This is second hand information from various windsurfboardbuilding sites, but anyway: The “cheatering” is used to seal the blank so the epoxy used for laminating does soak into the blank. If the resin soaks into the blank, the glass would not bind very well with the blank. I guess it’s a bigger problem with windsurfing boards where they really push for less weight and more strength, using very little resin, vacuum bagging and ‘exotic’ materials, multiple layers sandwich constructions, carbon fibres, etc. In a ‘regular’ epoxy surfboard I guess you could just add a little more resin if the blank soak. Still, every manufacturer of epoxy have their own code for how to lay epoxy on hard epoxy. Some only require cleaning for a good bond, most the regular sand and clean. Bdw. why do you use EPS(or bead foam/isopor™) and not extruded styrofoam? I thought EPS soaked more water then the other and was harder to shape then extruded styrofom, or is it the other way around? Best regards, Håvard

I am using beaded foam just because it is what is available/affordable. Peter Rijk tried to turn me on to styrofoam that apparently available and cheap in the Netherlands. I wanted to get a block of the stuff to try my hand at making my own blanks. I searched on line for about 3 weeks and found nothing that was even remotely close to the dimensions I needed, let alone the price. I was quoted $95 for a 4’x8’x3" sheet (Dow styrofoam). That was the thickest they had.

I am using beaded foam just because it is what is available/affordable. > Peter Rijk tried to turn me on to styrofoam that apparently available and > cheap in the Netherlands. I wanted to get a block of the stuff to try my > hand at making my own blanks. I searched on line for about 3 weeks and > found nothing that was even remotely close to the dimensions I needed, let > alone the price. I was quoted $95 for a 4’x8’x3" sheet (Dow > styrofoam). That was the thickest they had. Haavard, I posted this to you previously, right before you posted that you had decided to use expruded polystyrene for your blank. Beaded expanded polystyrene (EPS) has a closed cell structure which expanded styrofoam construction foam lacks. From the websites and articles I’ve read, and from the pros I’ve talked to, EPS soaks up far less resin, and has far less capillary action when used in surfboard construction. Capillary action is one of the factors which cause surfboard skins to bubble up after lamination. Sometimes long after surfboard completion. Foam capillaries wick resin into the blank, causing a buildup of air pressure inside the blank. Extruded construction styrofoam is the material in EIFS or “fake stucco” which is the subject of $hundreds of millions in lawsuits here in the United States. The problem? Capillary action. If any rain water gets to the styrofoam stucco underlayment, the foam wicks the rainwater into itself, and transfers the water to all wood which contacts it. The wood then rots and ruins the house. I’m willing to try anything after it’s proven, but lots of people have reported problems with expanded polystyrene. I can see why shapers would try “cheatering” to seal expanded foam. Why not just use the right stuff, EPS?

Haavard, I posted this to you previously, right before you posted that you had decided to use extruded polystyrene for your blank. Beaded expanded polystyrene (EPS) has a closed cell structure which extruded construction foam lacks. From the websites and articles I’ve read, and from the pros I’ve talked to, EPS soaks up far less resin, and has far less capillary action when used in surfboard construction. Capillary action is one of the factors which cause surfboard skins to bubble up after lamination. Sometimes long after surfboard completion. Foam capillaries wick resin into the blank, causing a buildup of air pressure inside the blank. Extruded construction styrofoam is the material in EIFS or “fake stucco” which is the subject of $hundreds of millions in lawsuits here in the United States. The problem? Capillary action. If any rain water gets to the styrofoam stucco underlayment, the foam wicks the rainwater into itself, and transfers the water to all wood which contacts it. The wood then rots and ruins the house. I’m willing to try anything after it’s proven, but lots of people have reported problems with expanded polystyrene. I can see why shapers would try “cheatering” to seal expanded foam. Why not just use the right stuff, EPS?

The whole fish eye thing is what has me buggin’. Hopefully someone will > post reasons why this happens, so I can avoid it. The “Fish eye” thing happenes to me when it’s hot outside. I don’t know why. I started making my hot coats a little bit thinner and it helped alot. I have heard and learned that a poly hotcoat on an epoxy lam is a big NO NO! Not good to mix materials like that and it makes for a weaker board. You won’t find out till the board as been sold and the customer comes back a yaer later with his coat falling off! Also…just to put in my two cents on EXTRUDED foam. It bites, blows, sucks, I hate it. I used almost twice as much resin laminating a extruded foam board as opposed to a NORMAL beaded foam board. Pluss there were other problems like gassing at the stringer in the top lams etc. I hated life when I had to work with it. Just an opinion though. Maybe it has it’s plus side

Haavard,>>> I posted this to you previously, right before you posted that you had > decided to use extruded polystyrene for your blank. I don’t think I read that post. Stupid me. [snip] > Why not just use the right stuff, EPS? Didn’t know it was the right stuff, I think I got the two mixed up. A few reasons I didn’t think EPS was the right stuff: 1) I’ve never thought of EPS as strong. It breaks fairly easy. Styrofoam is supposed to be stronger. On the other hand, I have no idea how strong polyurethane foam blanks is as I’ve never seen or held one(thus never tried to break one) 2) Beaded foam must be a b***h to shape. I’ve tried sawing the stuff and that was no fun. I guess I’ll have to make some kind of hotwire thingy. I’ll think I’ll go for the EPS as it’s available and cheap Thanks for the help, all of you. Bdw, what kind of density are your EPS blanks and how heavy would you glass a EPS/epoxy (long)board? Best regards, Håvard

[snip]>>> Didn’t know it was the right stuff, I think I got the two mixed up. A few > reasons I didn’t think EPS was the right stuff: 1) I’ve never thought of > EPS as strong. It breaks fairly easy. Styrofoam is supposed to be > stronger. On the other hand, I have no idea how strong polyurethane foam > blanks is as I’ve never seen or held one(thus never tried to break one)>>> 2) Beaded foam must be a b***h to shape. I’ve tried sawing the stuff and > that was no fun. I guess I’ll have to make some kind of hotwire thingy.>>> I’ll think I’ll go for the EPS as it’s available and cheap Thanks for the > help, all of you.>>> Bdw, what kind of density are your EPS blanks and how heavy would you > glass a EPS/epoxy (long)board?>>> Best regards,>>> Håvard Haavard, I use 2 lb/sq ft EPS for surfboard blanks. Yes, a hotwire thingy is the right tool for cuting a blank out of an EPS foam billet. The top view will be rectangular. You can use a sabre saw (reciprocating saw) to cut your outline from the blank, but stay about 1/4" (almost 1cm) outside the line. Use a long saw blade with maybe 12 teeth per inch, and don’t push. A hotwire thingy would probably work better for cutting outlines, but you would first need to make a cutting template. You’re right, EPS is weaker, springier. The Idea is to add fiberglass which will take advantage of EPS’s properties. Shaping EPS is easy. Removing EPS beads is a good thing when shaping far above the finished shape. Removing foam goes much faster that way. When working close to your finished shape you should use finer sandpaper, mounted on foam, mounted on wood. That’s when you start shaping foam. As you remove foam with this method, you also depress it, forming a denser foam skin. Good luck.

I use 2 lb/CU ft EPS for surfboard blanks.

Noodle - can you not cut EPS with a hand saw when cutting the outline? Thanks, P.V.

Paul, Not to discourage you from building an epoxy board (I think that’s cool). But if cost is your primary consideration, its probably not the way to go. I too live in the Houston area and have been faced with expensive shipping costs of Clark blanks. However, when you consider that 3 blanks fit to a box (typically) the cost per blank for shipping drops to around $33. The last time I checked epoxy resin is three times more expensive than polyester resin. And, as Noodle previously stated Styrofoam requires more layers cloth and resin. So, you will actually end up spending more to build board using one of Fry’ blanks. If you think you don’t need three blanks, you may consider encouraging a few friends to put together an order together. This is what I often do. Or, as anyone from this site will tell you; once you start building your own boards you won’t want to stop. So, purchasing three at a time is not a bad idea. Good Luck, Thomas Noodle - Are you getting your E.P.S. blanks from Henry Fry in Pasadena > TX.? I am wanting to try to shape my first board but the cost of getting a > Clark blank is a killer. I can get a blank from Henry alot cheaper. 2 > questions on epoxy. 1. Is it alot different to shape the E.P.S. as opposed > to a poly. blank? Do you use the same techniques? 2. I have never glassed > a board and I have heard some nasty stories about epoxy. Is it difficult > to use? Thanks ahead of time.>>> Do you live in the Houston area? Thanks again, P.V.

Great point I have not really thought about it like that. Maybe in the future if you need someone to go in on blanks, we could help each other out. I like the idea of lowering cost as much as possible. Thanks, P.V.

Great point I have not really thought about it like that. Maybe in the > future if you need someone to go in on blanks, we could help each other > out. I like the idea of lowering cost as much as possible.>>> Thanks, P.V. Paul, I had not planed on building any more boards for myself this year. But, I had thought about building one for a friend of mine. So, if you are interested I can be counted on for at least one. I also, know a guy in your neck of the woods (Woodlands) who also likes to build boards. He too might be interested in getting another blank. If you would like to discuss this further, you can e-mail me directly through the board I posted in the Board Archive. Look under the Gun section, at the bottom. -T

Noodle - can you not cut EPS with a hand saw when cutting the outline?>>> Thanks, P.V. I’m sure a hand saw would work fine, but I’ve never tried it. -Noodle

Paul,>>> I had not planed on building any more boards for myself this year. But, I > had thought about building one for a friend of mine. So, if you are > interested I can be counted on for at least one. I also, know a guy in > your neck of the woods (Woodlands) who also likes to build boards. He too > might be interested in getting another blank.>>> If you would like to discuss this further, you can e-mail me directly > through the board I posted in the Board Archive. Look under the Gun > section, at the bottom.>>> -T One can buy very light,probably about 1 pcf, EPS foam in Home Depot atleast in Florida. The best foam to use is EPP: Expanded polypropylene as it is truly resilent and comes right back so pressure dings are about non existent.Though it really comes off in chunks probably worse than EPS and is more difficult to get thing to adhere to it. It is more chemical resistant than EPS and one might get away with polyester resin though I have only used epoxy. As an alternative consicer Arcel - it is 65%EPS and 35% polyethylene and is much more resilent than EEPS but not as much so as EPP but things adhere to it better and is otherwise very similar to EPS but tougher and pressure dings are less of a problem because it is multiple impact while EPS is still considered single impact. All of these things are well known in the packiging industryyI have gottne several free samples of EPP foam and am on my second board. The first one takes water really bad as I did not use fiberglass cloth. Hope the second turns out better.

Hey Noodle a quick question for you if you may. Is there a viable way to thin out epoxy? Thin it enough to spray? Maybe just enough to get a thinner coat? Thanks

Hi surferbbrian -

I haven't heard anything from poster known as Noodle for quite awhile.  You might try reposting under general forum.

My .02 - you'll likely have a hard time getting epoxy thin enough to spray.  As for general thinning, there are at least a couple of solvents (Xylene and Acetone) that will work but they all seem to affect the material properties of epoxy in a negative way.  At least one good source has posted on the internet that heat is the best way to thin epoxy without affecting the strength.

Also keep in mind that some of the solvents may affect the foam itself.  Acetone for instance, melts EPS on contact.

Thanks John, all good info, I ordered some additive F and will look into the heat aspect. it sounds like anything else will be a bit sketchy.