Ive been glassing a few PU blanks with epoxy lately and notice that it seems to trap air under the cloth while laminating. little bubbles 1/8" or so. They can be squeeged out for th most part but it takes a lot of effort. Which is so unline when i glass eps. wet out let the epoxy soak in, squeegee off excess and done…no problems there. Anybody else have this issue? could it be the cloth im using(hexcel)? i would more likely think that it has something to do with the density of the PU foam compared to EPS but im not sure. Just curious if anyone else notices this difference when glassing epoxy on a PU blank.
Were you using the exact same cloth on the EPS boards? The reason I ask is that it seems more likely to be cloth related… specifically, a tighter weave. Something else besides weave might be how the cloth is finished - Silane vs Volan vs ? There are some weird fabrics out there, some of which aren’t the most friendly for surfboard work.
Same cloth standard hexcel 6oz E glass. Its strange because when i glass an eps board there are bo problems what so ever i dont even have to think about it.
Are you in a temp controlled room?
You say this is recent.
Not sure where you are but it’s winter here and cold.
If you glassed the eps in the summer with better flow that would possibly explain it.
If your glassing clear get yourself a bubble buster and your all good.
Yeah its colder now (east coast) but this has been happening since a few months back when it was warmer. I noticed poly glassers are more aggressive with their squeegee work. Is this because of the foam or the poly resin?
Having gone back and forth from Poly to Epoxy many times; I find Epoxy to layup easier than Poly. If you are getting bubbles in your lamination, you may be over stirring your Epoxy in the pot prior to lay up or over working with the squeegee. Poly resin is always a lot of work, especially with Hexcel. You’re constantly going back looking for bubbles with Poly. Dry spots on the flats and bubbles on the rails. I think that because I have worked so much with Poly over the years that Epoxy is pretty easy. I don’t think in your case it has anything to do with the foam or the cloth.
Do you seal your eps foam before lam ?
I use to seal my eps and found it’s far easier to have a bubble free lam even more with multi layers of glass at once. I do same know when i lam epoxy over pu because like you i had some bubble when i lam straight on foam. So i cheater coat foam with à bit of époxy let dry and scuff before lam and or lam direct on wet to tacky coat to avoid blush problems. More work first but less after…
Good advice. I know guys who seal with Epoxy the night before whether Glassing EPS or Poly.
I dont seal my eps. I find it to be a wasted step and my eps shapes clean. Interesting advice thanks guys ill try a few new things
i don’t seal foam for esthetic but for consistency in weight and quality. it’s come from my industrial background where we seal everything porous before cover. i try all kind of sealer and no sealer too, know i use epoxy past on eps and straight epoxy on pu.
I’ve noticed when glassing with epoxy that if the resin is thin it drains out of the cloth. I think that is what the OP is experiencing. Perhaps adding a tiny bit of thickening agent to the mix would help eliminate his issue. Could also be contaminated cloth so that the resin won’t bond to the fibers.
A throw away cotton mini roller is a handy tool to have around when you are laminating Epoxy or Poly. If a rail starts giving you trouble or you are worried about your resin setting to fast; a small 3 inch roller will really speed things up when you are trying to get those dry spots on the rail or have recurring bubbles. I prefer the tighter nap covers. The longer nap covers hold too much resin. I have trouble with bubbles mostly on boards with hard rails, hard tucked edges and butt cracks. Be careful using Cabosil to thicken resin. Add to much and your resin will set “cloudy”. I use it the way Loehr uses it in his video Epoxy 101. To set fin boxes and occasionally putting a little on my finger and forcing down those butt cracks.
Just had this same issue again. Anyone ever have this problem? I think it might be cloth related but really not sure. 6x4 over pu using rr quick kick
Never had that happen with Epoxy over Poly or Epoxy over EPS. I think you’ve got some kind of temp or room problem. Probably not cloth related. The problems I have with Hexcel are saturation, small air bubbles around hard rails and strings. You were right in your earlier post when you stated that Poly glassers are more strenuous in their squeegee work. You may be pulling to hard with the Squeegee. Next time try a “cheater coat”. After you have everything saturated and tucked, pour on an amount of resin on and squeege that off. The cheater coat makes sure everything is saturated. PS looking at your photo again; It appears you are not sealing or Spackle? True? Because those “little bubbles” looks like pin holes in the foam.
The cloth is all definitely fully saturated. Its bubbles underneath the lamination. Here are maybe some better pics. These pictures are post hot coat. Not pin holes from a dry lam. Polyurethane millenium foam…no need to spackle. Shape was clean without gouges. Perhaps blank and resin are too cold however and resin could not flow into the micro holes contained in polyurethane foam? As i know it is very smooth but definitely a pourous surface still. Resin research quick kick is one of the thicker resins out there as well.
Yeah wasn’t thinking Poly Blank. I shape and glass Millennium all the time with Epoxy and Poly. No problema.
What temperature range do you glass them in?
I live in Oregon. My “car and a half” glass shop has a 110 wall heater that I usually flip on the nite before. I suppose I should put a thermometer in there and check sometime. It’s well insulated so by the AM it is “short sleeve warm.