I'm shaping a 5'9" quad from Marko superfused EPS foam. I've shaped (non superfused)eps blanks in the past but always sealed them. Id like to keep the weight down and the superfused foam is noticably different than normal EPS with no voids. Weight is an issue on this board and I'm thinking i can get away without sealing it. Any thoughts? Incidentally i found this on Swaylocks from a prety well known shaper: "they mold their EPS blanks instead of cutting them out of a block. Their website claimed this makes the bead bonding so tight that you do not need to seal them prior to glassing - well I was skeptical but they deliver on their claim! I could not believe how solid the foam is and how smooth it finishes out! This stuff tools almost as well as urethane"
If you frequent Sways, you know you're opening a can of worms. As far as I know, there is no "superfused" blanks offered by Marko that's any different from the standard pressure molded, virgin foam in 1.9 lb density and higher. If there is, let me know where you found it, please! Their foam is considered "superfused" because it's molded and fused in such a way that they say the beads become water tight. US Blanks advertises their foam as Superfused, so it's really a marketing strategy, IMO. I've worked with US Blanks 2 lb density and Marko pressure molded foams in 1.9 and 2.1 lb densities, and I seal. I recommend sealing if you're concerned with weight, as the foam will absorb some resin. Not much, but if you're going for grams, seal with lightweight spackle, especially if you don't end up with a smooth finished surface, because each little divot holds a tiny pool of resin. If you're going for durability, either don't seal, or seal with a resin/microballoon slurry. If you're using lighter density foam, you'd better seal, as lower density foam will absorb more resin than higher density foam. (I assume you're doing a hand layup?)
LBCrew - I really appreciate the feedback. I used the term "superfused", but i should have just said the blank is Marko "molded" EPS. I was on a bunch of websites doing research last night, so i just had the word "superfused" in my head. It is probably the same Marko pressure molded foam you have shaped. I'll probably just go ahead and seal it...whats a few ounces right? C3...thank for chiming in...i'll show you the board when its done..
i don't understand why anyone would use water based spackle......if you get any water penitration will it delam? I just go to a 220 finish screen and hand glass it super light and very durable so far. I even glassed one with a single 4 top and bottom with a patch and the thing felt like a feather. Not sure how its holding up but he just ordered another one so he must have liked it.
were on the same page...i dont plan on using water based spackle to seal it..epoxy resin with q-cell thickener. The way i look at it @ $50 / gallon 8 oz of epoxy resin seals both sides for $3 so why fool with a foreign, water-based layer between cloth and blank. Just my thought..based on nothing scientific. Glassing schedule just like you said...single 4 bottom, single 4 deck. 4 oz patch on the bottom around the fin cluster, and another 4 oz patch on the deck from rear foot to front foot and spilling over the section of the rails where you grab duck diving. The 5'11" fish with the natty boh man i posted in the "groveler" thread is glassed like that and after maybe 20-30 sessions is holding up fine.
Unsealed EPS blanks will absorb about 5% more epoxy, I've done tests.... boards weigh a bit more. You don't need to seal EPS if you use Resin Research's new Quik Kick Epoxy. It's more viscous and doesn't seep into the blank. Sets up quicker too so no drain time. Otherwise use DAP Fast n' Final lightweight spackle mixed with bottled water (tap water will yellow) and squeegee it on. I've sealed and glassed somewhere around 60 EPS boards with DAP and not a single problem with delams to my knowledge. Sealing with epoxy is a waste of money in my opinion. Yeah, there's a better bond with the lam but if the board doesn't delam anyway, what's the point? Marko and US Blanks call their EPS blanks "superfused" for marketing purposes. The EPS beads are expanded in a mold similar to how a PU blank is blown - but different. ~Brian www.greenlightsurfsupply.com
Lightweight spackle has been the industry standard for more than a decade, but everybody has a reason for doing what they do, so if that's not to your standards, do something else that you're confident will work. I'd stay away from q-cell (Cab o sil), though. It's a strengthener and thickener, but is not used to reduce weight. I use "hollow glass microspheres" made by 3M. It thickens AND reduces weight. Mix up a batch of 50/50 by volume microspheres/resin-hardener mix and adjust it from there with more bubbles if needed. I like it to be the consistency of thick honey - it should barely flow. Use a spreader and give it a thin film over the whole thing, filling in all the divots. When cured, wipe (don't sand) with 150 grit so your cloth won't snag on it when you lay it out. Be sure to wear your particle respirator when working with the stuff... otherwise you'll be calling the law firm of Sheister, Swindle and Fanagel to handle your mesothelioma law suit case.
Thanks greenlight and thanks LBI crew for the help and advice. I really appreciate it. I'll stay away from the cab-o-sil and get the microspheres if i decide to seal with the epoxy mix. Brian, whats you experience with actual work time for the Quik Kick epoxy at say 75 degrees or what ever work glassing environment you use? Can the kwik cure also be used for finbox installs / leash cup etc where heat up problems can occur?
GL says the pot life of KK is 18 min. at 70 degrees, and 14 min. at 80 degrees; set times are 1 1/2 hours and 45 minutes for the same temps, respectively. He also says KK is fine for box installs, but not FCS plugs in EPS. Poly is OK because there's no melt down risk. Here's one of my personal experiences... Did a 5 color resin swirl bottom w/ cutlap using KK over PU foam. Room was a dry 68 or 69F. Mixed my pigments into the cups of resin and Add F, then added hardener, mixed thoroughly, and got right to the dirty work. Plenty of time... I'd say 20 minutes start to finish, without any problems moving the stuff around. I expected it to be much thicker than it actually was... about as thick as regular 2100, really. Colors came out good for epoxy, possibly a bit better than 2100. Concerned about the possibility of rapid thickening, I did not paint the lap area of the rails before I poured it out on the flats... just poured it straight out, spread it around, and pushed it to the rails. Gave it a minute to soak in, then wetted out the laps and gave them a tuck. Went back to the flats and did my first pull, squeezing the resin into the lapped cloth firmly. Went all the way round and then back to the flats, doing my last pull, and putting a finishing tuck on the rails. Went back around with a brush to hit a few dry spots and clean it all up. Meanwhile, I had telescoped a couple of blank boxes and put an electric space heater in one end, and closed up the box to get it as hot as it was going to get. I estimated the space inside the box to be about 90-95F. As soon as the board was laminated (again, about 20 minutes after mixing the resin) I put the board in the hot box, set up on a couple of stacked rolls of tape, and closed up the box. About 30 minutes later I pulled it out and the flats were pretty much tack free. I smashed down a bubble or two in the swallow tail area, and they stuck right down. After 30 minutes in the box (50 minutes after mixing the resin and hardener) I cut my lap. Clean cut, no gummies. I could easily have pressed down the lap edge, but forgot. That would have been the perfect time to do it. Installed Proboxes using KK with no issues, except the resin seemed to push the boxes up as it was setting. Had to push them back down. Never saw that before. Next time I'll just use my shaping weights on top of a sanding block to keep them snug and flat.
Yeah, I'd say 20 minutes working time at 75 degrees is pretty right on. It starts to get tacky at that point and the flowability decreases a lot. It's plenty of time to get a nice lam finished. Like LBCrew did, I made a hotbox and put the boards in there to speed up the cure after each lamination. It's awesome. If you need a telescoping blank box to make a hotbox let me know. I just dropped some ProBoxes in with Quik Kick (Also termed Kwik Kick) and they did not float. I only fill about 1/4" routed hole depth with resin and drop the boxes in, then finish around the outside with a dixie cup... ~Brian www.greenlightsurfsupply.com
