Just basically after a bit of guidance counselling I guess; talk me into it, or talk me out.
Contemplating a build out of Xps and epoxy. I live on a little tropical island and the humidity here gets beyond the scale of 100%.
Here are the issues I’m unsure about.
My glassing would not be done in a controlled environment; most likely a tarped off carport or a mates shed.
I can only get my hands on Ados and Nuplex epoxy.
It’s going to be a SUP (please don’t judge me, the lagoon is way to beautiful here to not want to go explore flatwater cruising. I can only get 8’ x 4’ x 40mm sheets of Xps, so that’s going to equate to a shit load of glue. I soon realised the Gorilla glue we get here is a completely different brand to what you US crew get. So thinking the only solution here is as to epoxy and micospheres filler.
Was thinking of tinting resin to cover all the ugly joins. Could this add further potential pitfalls?
Keen to give it a crack but not into wasting a whole lot of money, time and effort.
Be wrapped with any advice, pointers or words of (dis)encouragement you may be able to offer
A problem you may have with the epoxy is amine blush. To avoid amine blush, it would be best if you can get all of your laminating and hotcoating done in under 24 hours, from start to finish.
Thanks for that extra spanner in the works there stoneburner, good oil all the same. I’m baffeled by all his reading up on the idocencricies of epoxy now. Some say glass with falling temps to avoid milky cure, pin holes etc. And, then others advising best to apply during rising temps to avoid amine blush. I can’t control the weather here, nor my glassing environment. So is it really worth the gamble? Cheur
I used to live in Houston, Texas where it is commonly 95% humidity and 90-100 degrees… I glassed a board in my garage where it was 90 degrees with 95% humidity and it worked out fine – at 90 degrees, even with the slow hardener epoxy cures pretty fast…
I was using MAS epoxy with the slow hardener when I glassed a board at 90 degrees; I have also glassed several boards with Resin Research CE at 80+ degrees and high humidity with no issues.
Anyway - with your XPS, epoxy is glue, so (please chine in if I am wrong) I don’t think you need filler (micro ballons) when glueing the sheets together…
Sometimes you have to go with what you have in the barn.
I believe pinholes are the result of air heating in the spaces between the beads of EPS, causing the air to expand.
XPS is closed cell foam. Only the few “very small” cells ruptured during shaping can release expanding gas resulting from heat. After you do the final sanding prep of the foam, let the board sit and heat in the shaping shed/hut for a day or two. Cover it with a clean sheet so dirt and dust do not settle on it. Most of the few damaged “small” surface cells that might rupture should have ruptured. After that, there should not be much expanding gas left to deal with. In your situation, this is how I would approach it.
Morning condensation/dew on curing resin can cause amine blush. If you can laminate and hot coat both sides of the board before sunset, only the hot coat can get amine blush. You should be able to wash amine blush off with soap and water, and an earnest effort. If you do not gloss coat, amine blush should not be that big an issue.
Sealing with a coat of water-based acrylic, low-lustre concrete/tile sealer after a hot coat final sand should take care of any pinhole, should any develop.
If you really want to build your own board, go for it.
I suspect Shark-Country and Oneula can offer insight about shaping and glassing XPS boards in warm humid island conditions.
I wouldn’t worry about doing it outside in the elements. In my humble opinion, epoxy isn’t that sensitive. The only issue I ever have is getting that perfect gloss coat, but that is a different story.
Just make sure you apply it to clean surfaces, and mix accurately.
I would rather do it in the heat, since the epoxy flows better and cures quicker. Also when I say it isn’t that sensitive, I f’ed up on my second board, and it rained on the hotcoat before it hardened. I put it inside, and the following day it cleared up and looked fine. I am not saying to do it in a windy location with dirt flying around, but if you are making something for yourself, you are good.
Point being don’t worry about that.
I would be concerned of the type of epoxy you are using, assuming it is not surfboard epoxy. Make sure it is UV friendly, and not too viscous, so you can wet out cloth.
For gluing the sheets together, it was recommended to me to make slices with razor blades to make sure things stick.
Otw have fun, give it a shot , make a build thread, I would be interested.
It will be fine…i just got done doing a 9’6" long board in the “tropical Southern california” weather. it’s been hot and humid here. Live by a few rules with epoxy. 1) mix to the right ratio, either by volume of weight…it doesn’t matter…just get it right. 2) use a clean bucket, on that is meant for solvents etc…don’t use a red beer cup, of something dug out of the trash can. 3) laminate the board properly, same goes for a poly board…there is a right way to do it…won’t go into it here. 4) if pressed for time, do one side of stringer in one batch, then do the other side with another batch.
xps will out gas, so you need to leave the surface of the foam rough, I mean like 50 grit rough…do not make it smooth and pretty. Also use quite a bit of glass when laminating, a thicker glassing schedule will help keep the board tight. Do your glassing when the temp is falling…do it in the afternoon or later…the blank will be sucking instead of blowing.
Also, don’t pigment of tint the board…when you are done…paint it with auto paint of good old krylon. if you try to do color work in the lay up…it will look like crap. And with that kind of epoxy, if you add enough colorant to hide everything, it will take so much colorant that you will change the properties of the epoxy and it will be rubbery / flexible when cured…trust me I know this.
Humidity sensibility of epoxy depend of technology used. Some are really sensible, often the cheap one. You can have blush immediatly after start of reticulation so do a test with your resin. Always better to work in warm space. If you doubt go with usual procedure : let cure then clean surface with scotch brit and water, sand light with no more than 80grit work every time but not always necessary.
Hey thanks heaps crew, really appreciated. Ok I will bite the bullet. Thanks for the peep talk.
Anyone used Nuplex epoxy? NZ,OZ. It’s not surfboard epoxy. Only other I can get my hands on here is ADOS, but I thnk it’s pretty crap as my mate used it for repairs here and it went yellow and gummy, possibly his bad thou.
Not fussed about asthetics or top notch quality as I don’t intend to surf it. Just needs to float really.
Was intending to use micro ballon filler just to make epoxy glue go a bit further and plus it’s white
Teaching my young boys to swim at the mo so might experiment with a flutter board first up.
Epoxy will go further the more viscous it is. Put it on thin and let it wet out…let it soak in to the cloth. Lots epoxy boards are make heavy because they don’t understand how it works. Epoxy will not be forced into cloth it needs to soak in. And it doesn’t take much to wet out the cloth. If the cloth is touched with epoxy, it will wet out., but it needs time to soak in. Adding micro balloons will thicken it up, clog the cloth, add weight, and won’t adhere to the foam as well… Just use plain epoxy that is about 70 to 80 degrees warm you will be fine. And when in doubt, just do the board in small increments. Epoxy bonds to epoxy.
don’t now your flavor of epoxy, but in Floriduh, where it is usually 90something with 70-80something humidity, we do happy hour glassing if you don’t have AC. Wait till you get off work, pour a drink, talk about glassing based on if it’s going to rain a lot, perhaps a little, or maybe not, and either do Kwik kick to do both sides, or perhaps just fast and do one side and if you have enough to drink, both sides like in the old days. It will be a falling temp, and you will have left the blank out in the toastiness to soak up all that heat so it will want to let go of it and soak up any little bits of epoxy juice during the lam to avoid those nasty little pinholes. Good luck!
I’ve used both Nuplex and Ados. They both work fine. I bet your friend that had trouble with Ados didn’t use the right mix ratio. I’ve used stuff from the back of the shed that’s sat around for a decade and still went off reliably. Nuplex makes a few different epoxies. I know of at least one glass shop here in NZ that uses their clear surfboard epoxy. If you live off the beaten track I suspect that you are probably getting their generic boatbuilding epoxy. I keep a 20 litre jug of this on hand. It seems like my local paint shop always one brand or another on sale. It’s really useful stuff and about half the price of clear surfboard epoxy. It will turn yellow and it does blush. I don’t think laminating and fill coating within 24 hours is a reliable way to avoid blush. Personally, I laminate both sides and let it go off completely, then scrub it with a green scrubber and rinse with warm water, then fill coat when it’s dry. I mainly use this type of epoxy under composite skins, though I’ve used it for the outer glass on quite a few boards as well. Both Nuplex and Ados are a lot like West Systems or a number of other epoxies-generic. If I use it for outer glass I always paint over it, because it yellows. The best is 2 pack boat or car paint, but the stuff is really toxic. I dont’ have the right protective gear. A friend who paints cars who has done a few boards for me, but if I’m doing it on my own I use a single pack boat paint and roll it on.
A paddleboard is a lot of area to cover, particularly if you haven’t done a lot of laminating. Like Resinhead said above, you can mix small batches and take your time. Since you are in the tropics I’d use a slow hardener. I’ve laminated during summer cyclones and haven’t found humidity to be a big issue.
I don’t have a lot of experience with XPS but I have joined lots of sheets of EPS. Epoxy keeps them together well but the hard glue line is a pain in the ass to shape around. Gorilla glue works pretty well for EPS and isn’t too bad to cut through when shaping. Hope this helps.
BTW, for XPS, pinholes should not make a lot of difference because it is a “closed cell” foam – no interconnecting air spaces like those in EPS. The big advantage of XPS is that it does not soak up water, because it is closed cell foam. If you have it, a water-based acrylic concrete/tile sealer for a final coat should solve any pinhole problems anyway.
I believe it was GregTate who advised using a “small” paint roller with a 6-mm nap cover to apply a **thin coat **of expoxy to the sides of the foam sheets to be glued together. Use your template to mark the board outline on each sheet and leave a 3-inch epoxy free margin inside the outline drawn to help minimize epoxy glue-line sanding issues. Since you will likely be working with a very large surface area for a SUP, you might want to do a litle testing first on a sheet of XPS to see what size paint roller and nap would work best.
Wow. more good oil. Kia Ora; thanks. And good to hear from a few fellow kiwi shapers.
Not living in NZ, but yeah it’s the generic stuff I can only get hold of here. As stated it’s just a SUP so no need for top shelf quality.
Might take the punt on ADOS as it’s cheaper here. Thanks Jong. What gorilla glue are you using? as I noticed the NZ one is not the same as US brand. The gorilla brand I know does a variety of glues, but mostly construction type adhesive for drywall GIB etc.
Good luck King. You better post some pictures. Don’t make us come over there. If you just drift off and we never hear from you again, we are going to be pissed. ha