The title pretty much sums up what im wanting to know. I bought a second hand board and the first day out on it i managed to blow the fin plugs. I am waiting to replace the plugs but im not to sure on what fix i should be using as i have heard people saying that some resin etc can eat away the foam on some boards and i really wouldnt want that to happen! How do i tell whether the board is made from polyester or epoxy foam and also what is the best fix to use for these when replacing a fin plug?
Polyester and epoxy are the types of resin used. Polyester resin will eat polystyrene foam. Converesely, epoxy resin won’t damage polyurethane foam. If you have damage and the foam is exposed, take some good, clear photos and post them here. Most here can tell the type of foam by seeing a photo. One way to tell, but you have to be somewhat clued in, is polyurethane foam has a smaller cell structure than the other types (EPS, XPS, etc).
If it’s a PU/PE board, no need to use epoxy, as it costs more.
Actually, there is no such thing as polyester foam and epoxy foam (at least in surfboard construction) but polyurethane foam and EPS (polystyrene foam). Polystyrene gets melted by polyester resin because it contains styrene. Polystyrene has to be glassed with epoxy resin instead of polyester. Generally speaking, polyurethane is glassed with polyester resin, polystyrene with epoxy. But you can very well use epoxy on polyurethane as well. So, using epoxy for your repair, you can’t be wrong.
This being said, if your fin-plug is gone, you can see what foam looks like. If it’s made of small BALLS agglomerated, it’s EPS. If it’s made of very tiny CELLS agglomerated, it’s polyurethane.
Ok, so i took a picture bearing in mind i used my phone. Can anybody tell that type of foam that is then? From what has been said i would guess it was polyurethane but considering i didnt know what that was 10 minutes ago, my guess could be and probably is entirely wrong. Any help much appreciated
Looks like polyurethane, to me. Sadly, the photo doesn’t help a whole lot.
Like I said before:
“If you have damage and the foam is exposed, take some good, clear photos and post them here.”
You could always do a small test spot. Mix up a tiny batch of polyester resin, and dab a very small amount on the exposed foam. If the foam melts, you need epoxy resin.
You will have problems if it is EPS foam. You will need more support to hold the plug in solid. Make sure there’s a small section in that hole that goes all the way to the opposite side’s fiberglass.That will attach the plug to the top for strength.
I use 5 minute epoxy for fin boxes in EPS foam, and laminating resin for polyurethane foam, and add a layer of glass. I have melted both EPS foam and Polyurethane foam when I’ve tried using epoxy resin for the boxes. The 5 minute epoxy gets hard before it can get too hot, so I like using that with EPS.
Either way, the photo you posted is not clear enough to tell what type of foam your board is made from. Take it to someone in your area who knows and ask. Maybe they can fix the board for you for a very reasonable price. A bad fin job will ruin your board.
Kinda… Sorry, Sammy, I guess we’ve been typing more or less at the same time… But your reply was more complete than mine, including XPS (which I forgot)…
You two were probably answering at the same time (check the times on the posted lines) - Sammy’s was a little sooner, and balsa was still typing, when you’re doing that, you don’t see the other reply going in ahead of yours.
I just like to thank everyone for all the help so far!
Yer i think ill probably just go with that ‘moonfish’ i was thinking of just buying this kit http://store.magicseaweed.com/Ding-All-Standard-Repair-Kit/Item/99/ and using that to do it. I guess it would still do a pretty good job, right? And ive heard if you mix in some small pieces of fibreglass with the resin you can get a pretty strong bond.
the kit in that link is a polyester resin based
repair kit. if your board is polyurethane foam then this kit is fine.
otherwise if your not sure stick to purchasing an epoxy based resin
repair kit. you can use these on a polyurethane or polystyrene foam
board.
Ah yer. I see what you mean. So do you think that would be strong enough to hold them in place then? Because, i mean i dont need it to be perfect, i just want it fixed but i also dont want them to pull back out after a few times out and have to by more plugs etc etc
Well epoxy is very strong. it all depends how you repair it my friend. heres a link to a site that will give you a great idea how you need to go about it. if you follow this closely it will be as good as new.
This is for a surftech but it will be basically the same for your board. the added patch at the end after eva fitted the plug is important to help with strength. most standard installs of fcs plugs like that on a new board built convetionally just have resin and filler set around it then sanded flush. but adding a patch will help keep it in there.
it depends how bad the damage is too, but i recommend a patch mate.
Thats a lot of help, thanks! I will order some of that epoxy resin and see how it goes from there. It seems like a quite easy job. I guess ill just take it slow and see how everything goes i will keep you posted.
i will keep you posted.