So I’m fairly new to board building and have only about 10 boards under my belt. I have always just done EPS with resin research epoxy and I’m trying to figure out why I’m getting trapped air under the glass. I have studied, read, and watched videos on techniques and try to follow them. I can’t figure out what causes the trapped air though. I thought for a while I was being to skimpy with the resin and so tried being more liberal…same results. I can basically pour resin on and begin spreading and some areas just immediately look like hundreds of small air bubbles are trapped, even the areas where the most epoxy is. After I wet out all the cloth and laps, it becomes a nightmare chasing all these out. Does it have to do with the pressure I’m spreading it or is this just something that happens? I watch my glassing 101 video and it doesn’t look like Greg has to deal with any of this…of course he has a bit of practice! I can literally sit for 30+ minutes and not get all of them out. Once it starts to set up, I can press really hard and hear the bubbles “snapping” as they are eliminated, but it just seems like an uneccesary step that I’d like to find a solution for. Any suggestions?!
deca, i would like to ad my2c… don´t be greedy with resin. i know some guys will tell you with how little you can laminate but it is much easier to " overload the lam and than squeeze the excess out then trying to bring resin in. same for poly. if my resin is on and i can hear the bubble burst ist not enough resin or/and not soaked in. give it time just spread it first.
salu2
not being at your side and physically seeing what you see is a tough diagnosis, but when I laminate, poly or epoxy, as soon as I have the flats and rails wet out, I pull from center to each end hard enough to dry out the cloth, this gets the fabric right against the blank.
Then back filling is easy, but air that was under the cloth and never thouroughly forced through the weave will be there to haunt you forever.
Also, I ALWAYS sealer coat my EPS blanks, this prevents drainage and blow
Any suggestions?
Slow down. Mix slow and steady. Mix slow and steady for 4-5 min. up and down , round and round. Slow. Pour out slow and steady. Move the resin around slow.....You have plenty of time...what's your hurry?
It's epoxy not a 7 min poly job....slow down...enjoy the ride......Stingray.
Hey Deca you may try this - worked for me…get your room hot…laminate…when you’ve lapped the rails and ‘finished’ turn off your heater and open the door. The room will cool quickly and the blank will start to suck instead of gassing off. Go back over with your squeegee afterwards…air should disappear before your eyes. But before trying this do as Jim said and seal your blank - I use spackle (lightweight waterbased filler diluted with distilled water) - others use a slurry of epoxy and microballons. Every time I lam with epoxy I see the air coming up under the lam and creating BIG bubbles - but as I say the dropping temp sucks them right back down again. Cheers Rich www.thirdshade.com
I have been suffering from the dreded bubles/ pinholes a little too mainly just in the rail area for some reason. i tried geting the room nice and warm (we suffer from the cold alot in the uk) and that helped but havnt tried turning the heat after laminating. Im familiar with gassing off on windsurf boards on a hot day in the sun so understad the thinking but was wondering do you need to do the tempreature drop on the first side as the blank is not yet fully sealed by the glass? is the spakle enuf to seal it and warent doing the tempreture drop? only reason i ask is a) heating the room then leting it all out is alot of wasted energy and b) its hard enuf to get the tempreture up to 20deg for curing so droping it down any fruther slows the curing alot!
many thanks
oh....I forgot it's winter in most of the surfing world......The Low Tech Lab never gets below 65* F.......we have heaters.....and nice outside temps.
the rules change when it gets cold....maybe you guys should wait a few months..........make your room smaller so it's easier to heat. Think room temp not massive heat going to the board.............
Hi Charlie, yes you need to do it both sides to prevent the trapped air - I guess the first side still suffers as the gas will be coming out all directions - Once it’s kicked I then post cure in a hotbox - that minimises wasted heat as it’s just the box you’ve heating and not the room - However, I ALWAYS cut the hole for the lease plug in the hotcoated board before the final post cure - this will allow the sealed board to vent whilst cooking. Cheers Rich www.thirdshade.com
consider yourself luckey! we are lucky if we see 65 in the summer! there are plans to build a new shaping room/shed that i can then control the tempreture alot easier but i work on some boards between 12 -19’ so its never going to be that small but thats a few mouths away as i have to get planning permishion.
What kind of cloth are you using. Are you using regular cloth, or some form of impact dense weave stuff. It sounds like the bubbles are under the glass and not from whipping the epoxy into a frothy mess?
But epoxy works with all kinds of fiberglass so it sounds like you are not laminating with the spreader, sounds like you are just moving epoxy around on fiberglass. Make sure you laminate too.
Remember epoxy is just glue for the fiberglass.
Do what everybody has said, and quit messing up.
Sealer coat and hard squeegee like Jim said, catch the excess in your container and reuse for the back fill. If you post-cure cut a vent hole as Thirdshade mentioned.
Sounds like really tight fabric to me. What cloth are you using?
I went in the grassing room with all these ideas above and confidence. Just using regular E glass Greg…4oz. I watch your video for techniques and making sure I’m not missing something. Same results as before…just areas that seem to hold the air. It doesn’t look like just 1 or 2 bubbles, but MANY that make up an area…some as much as 2"x2" patches. I’ve tried pouring more resin on them, pressing them out, pulling them out, etc. could the smoothness or unevenness of the eps be a contributor? I walked away from the blank not seeing to many in the lam, only to come back and see more than I left it with. The blank was shaped for a good 2 weeks beforehand, so not sure if gassing could be the culprit?
As others have said, sealing is critical, particularly with low density foam, or poorly fused, big beaded billet foam. The superfused, pressure molded stuff is much less likely to give you these kinds of issues. Also, your materials need to be warm. Warm resin, warm cloth, warm blank. Makes wetting out the cloth much easier. And I use Additive F… Greg says it helps wetting out, and I believe him.
As for glassing technique, I’ve found two things helpful… First, how you pour matters. I pour a thin ribbon of resin, and follow it with the spreader at a low angle. With a bit of practice, this will leave a thin, even film of resin all over the flats. Wating a minute or two before pulling gives time for the resin to soak into the cloth, which it needs. Starting to pull too fast leaves pin air in the weave. Let it soak in.
Second… Again with the spreader at a low angle, press the resin into the cloth and foam. The spreader will be almost flat… you’re using the side of the spreader, not the edge. You’ll hear pin air popping as you do this, and do this all over the flats. This does NOT work the resin and froth it up. You’re only pressing down, with gentle but firm pressure… not “working it in” like you do with poly. You’re sort of pressing it into the weave with the side of the spreader, and forcing out all the air.
Then start to pull, just as Jim describes. This works for me. It leaves a tight, flat lamination that’s fully saturated, with minimal waste. It even looks good over dark paint.
I would tend to think the seal is an issue then. Sealed right the blank doesn’t drain at all. Have you considered that?