so i finally lmainated my first EPS/Epoxy board. not entirely happy with the shape, but i learned lots and i think ittl be a fun ride. but after laminating the bottom, i was gettin bubbles coming up along the stringer. i glued the stinnger using ‘gorilla glue’ and a paintbrush, which was a mess unto itself becasue apparently that stuff expands when it dries, but i started to get a few air bubbles down the stringer.
anyone else ever have this problem? can i fix it with a little sanding and the hot coat?
My guess is that you had some outgassing from the blank during your lamination. I try to glass in gently falling temps to get the foam to breathe in instead of out, if it has to breathe at all. Ideally, you want to really control the temperature. I’ve also found that sealing with a resin mix helps limit outgassing. Others might debate that.
If the bubbles are small, poke into them with the corner of a razor blade and fill the void with resin. If they’re big and raised, you may have to surform them down and patch them. You really want a direct bond between the blank and cloth without resin in between.
nah, the bubbles are quite small actually. temperature is a problem. i put some studs up in my basement and made walls from 4mil plastic. hooked up a vent system through those little windows at ground level, and a shop vac with the the hose comin in through one corner so i can just sweep towards the corner and it gets sucked out. a togehter masonite floor so i can replace it when it gets too covered, a few space heaters, and hung a few thermometers around the ‘room’.
temp control can be tricky. but i can get it up to around 82F. so maybe start with a hotter room and let it cool down toward the 70 mark as its setting?
A couple of tips you might find using the search tool:
EPS is best glassed in falling temperatures, so heat the room first and then let everything cool down when glassing. This inhibits outgassing from the foam.
*note: The foam I get has very little gas problems but I understand that YMMV depending on the foam you get.
Some bubbles are actually a result from the mixing of the epoxy resin. You do need to swish it up quite a bit to ensure a nice cure but you may be causing bubbles to form. Some tips and tricks I’ve found on sways include heating the resin a bit (warm bath for the resinbucket, make sure no water gets to your resin though…), put the mixed bucket of resin in a bag and suck out the air with a vacuum, using a hot air blower to warm up the resin when you have laminated it.
Some bubbles do form when you squegee the resin over the fiber, the trick here is to avoid foaming the resin by using a roller or not to squegee with a lot of force or without making too many passes. The hot air blower method should help get rid of any bubbles resulting from your lam.
Now, you have some bubbles and your lam is hardened. You need to make sure that the bubbles don’t become possible leaks, sanding down your glass and then applying a hot air blower prior to applying a hotcoat should help you a bit. Why the heat? Epoxy actually doesn’t fully cure for days, by heating it up you soften it a bit and facilitate a chemical bond with your next coat. Be careful not to overdo the heat trick as you may actually cause discoloration and brittleness if you overheat the resin. I get a decent result with a standard hair dryer.
Your gorilla glue-up shouldn’t be a big problem, save the expansion properties of the hardening glue, just be aware that regular elmers type glue also works for glue-ups but the best is just epoxy.
Hope this helps, and be sure to abuse the search tool, there is a mass of info on sways!
the reason i think (now) its an outgassing problem is because the bubbles arent just space between the cloth and the stringer, they look like some little man was in there with a mouth fulla bubbalicious.
You should prep sand before hot coat, if that doesn’t expose bubbles then pop 'em like suggested before and sqeegie on your hotcoat so the resin is forced into those voids. Also important to have blank warmed up before glassing (or anything). We’re lucky to have an ac/heater from a motel room to control the climate, but back in the parent’s garage I’d sit the blank close to a space heater before glassing. I’m sure temps are a pain for you NJ guys, I don’t even know how you do it this time of year. I’m a pansy, I’m freezing my butt off in FL right now.
we survive by taking winter trips to florida. like i am spring break (march 9-16) and hope your fickle state gets a shot somethin good while im there and a my toes dont get nipped off by a grey man with the munchies. aha.
ill be in ft lauderdale with my first EPS shape for a week and a rented hyundai accent strapped fulla sticks that i know work:)
one last question. i obviously missed a big step in my research. i never ‘sealed the blank.’ do tell…
If it’s a warm sunny day, put the whole circus outside for about 1 hr. put the resin in the sun, put the blank in the sun. Let it warm up some what. Then take the traveling lamination circus indoors and do your thing, you won’t have any problems. Here in San Diego I never glass when it’s rainy, but we get a good varation of temps. in the am it can be semi cold 50-60’s but by mid day it’s 70-80’s. So letting everything warm up first in the 70-80’s then taking it back into the cool 60’s of the garage makes for a great bubble free lamination.
This can also work backwards if you want a bubbly lamination, just take your cold resin and blank into the warm sun and watch the little termite mounds appear.
Did you have big voids between your glue up? I’t might be the epoxy trying to fill the canyons of voids.
actually, there were. i woulndt necesarily call them canyons, but there were some voids. see, we got this huge block of EPS, made our own hotwire out of a car battery, guitar strings, and wood handles, screwed a rocker template into the block and hotwired out a rectangle board with a rocker. then i tried to cut down the middle with a circular saw. it actually came out greate xcept for the very end where the saw got turned sideways a bit becasue i got lazy and was reaching instead of walking along. so i desded to use the ‘straight’ edges that were the outside sides of the larger block. they actaully were pretty straight, but had a few ‘canyons.’ i was hoping the expanding gorilla glue would take care of them, but another intuitive point. thanks.
I am associated with a very big glass shop and they blow epoxy glass jobs on a daily basis.
My personal epoxy laminator sealer coats ALL of my EPS blanks before laminating and I NEVER have them blow up.
As much as I try to get the shop to pre-seal ALL of the other lables EPS blanks, they will NOT, as it takes up too much time and space, but they have time to grind out really large bubbles(football size) and delam’s. ( how much money/time was wasted tossing a full carbon board)
Take the time, one day added to the schedual and getting really good results. Seal with epoxy, give it a nice sanding and then get the glass job that you will be very satisfied with.
I seal with a 50/50 mix of hollow glass microspheres (3M’s “glass bubbles”) and epoxy/hardener mix. That’s my personal sealer of choice, but lots of guys seal with spackle. There’s a lot of debate over which is better, or if there actually is a “better” at all.
I’m convinced that the epoxy mix is better, so that’s what I use. I mix it up, then use a spreader and give the entire shaped blank a thin coat - barely enough to see. If the blank’s looking particularly shabby, I’ll do two coats, letting it cure and lightly sanding in between. I add some white pigment, too, to get a nice, white, hard, smooth surface to do artwork on and laminate over. The trick to a good sealer coat is spreading it on thin, but uniformly, and not leaving (1) ANY spots unsealed, and (2) leaving no “ribs” or beads of resin that flow off the corners of the spreader. That makes the sanding step, really, a “wipe” with 150 grit rather than a true “sanding.”
Search the archives for a lot of pros/cons of the sealing process.
As much as I try to get the shop to pre-seal ALL of the other lables EPS blanks, they will NOT, as it takes up too much time and space, but they have time to grind out really large bubbles(football size) and delam's.
ok, i think i get the idea, but one, i dont know what 3M’s glass bubbles, spackle, or what a spreader are. is the spreader the squeegie thing i normally spread the resin into the cloth with?
Spackle is what you use to fix holes in drywall. It comes in different weights, is water-based, and quick drying. You can buy it at the local hardware store. Just ask for lightweight spackle.
Spreaders are what you use to push around epoxy resin. They’re made of soft plastic and they’re stiffer than squeegees, which are for polyester resin and made of rubber.
Glass bubbles are silica (glass) “microspheres” that you mix with resin and used specifically as filler material. When cured, it’s a compound that’s easy to sand, limits shrinkage, and lightweight. 3M is the brand. Just make sure you use a respirator when working with the stuff… glass in the lungs is not a good thing.
ok, when u said spackle, i just didnt assume drywall spackle. ha. go figure. and i do have a ‘spreader’ i just like the word squeegie:) i got the technique, just not the terminology.
thanks a bunch, ill write next time somethin else screws up.
