Maybe someone can provide some insight: I am at the point of "coating" my Eastport Nesting Pram with "2 or 3 coats of unthickened epoxy." A a plan to test out the means of applying the epoxy, I decided to do the seats first. Well, no matter what I've tried, I cannot seem to apply the epoxy without ending up with a rough surface, due to, what I believe are sometimes called "microbubbles." They are barely apparent when the epoxy is in the cup, but I believe they are still there (a magnifying glass might help). At the same time, I also believe the act of applying the epoxy (with various kinds of rollers, mostly, introduces more bubbles.
I have tried: 1. Warming the epoxy, both mixed and each part separately, by placing cups (bottoms of) in warm water. 2. Making sure the room temp is 74/75 degrees F. 3. Tipping with foam brush. Tipping with bristle brush. (no difference) 4. Gray foam rollers as sold to me by CLC. (I think these introduced more bubbles.) 5. 1/4" nap rollers 6. Smearing on, by hand with a non-linting cloth, an extremely thin coating of epoxy first. This was when I thought the wood might have been outgassing for the first coat. It might have worked for that, but further coats had bubbles.
I have called CLC tech support numerous times to get advice (Liam and Terry now know to expect my calls)! In the end, Liam says I just have to sand them out.
Sanding them out creates more issues. Basically bumpy or "orange-peel like" surface with shiny spots surrounding where the bubble-induced bump used to be. If I sand any more, I will sand off all of the epoxy that I just applied (and cured).
Help! :) Is this standard, and it will happen on the entire boat? I've spent over a month on these darn seats, all supposed to be a "quick" experiment.
Oh sorry, ignore my last remark in the previous post. Here are some photos. Note that while I show only a small area, the bubbles are all pervasive over the surface, but I couldn't get the camera focused plus the lighting to show a wider area than what is circled in each pic. Also these were taken, I believe, after only one coat - I've since tried to do more, with different techniques as I mentioned in the first post, but it still comes out with bubbles.
Hi Laszlo, Yes I tried that. I tried very thin coats also - same problem. I have some photos but cannot figure out how to upload them here. It seems you have to provide a link to them, i.e. posted elsewhere like on your Google drive?
I had the same "issue", and I think the best approach is to do a couple more coats then sand it smooth. You're going to have to sand it smooth after the last coat anyway. I think it's likely these are lumps and not bubbles (like a couple others said) and they'll sand smooth in the end.
Have you tried foam rollers, which will introduce bubbles galore, but then tipping the surface with a dry foam brush? The bubbles from the foam rollers seem to be of the correct size for the foam brushes to get rid of, at least for me. When I do this I find it very important to make the epoxy coat as thin as possible. I usually go for 5 - 7 very thin coats instead of 2 - 3 thicker ones. That also minimizes runs and subsequent sanding. Any chance of some pictures?
I would not recommend switching to the West rollers since you have so many of hte gray CLC rollers.
After sanding (hopefully using a sander attached to a vacuum) and before applying epoxy are you vacuuming all the dust off the hull (and floor) and any nearby surfaces.
Thanks h and djdewitt. h, thanks for partly assuaging my fears that I was going insane, because indeed, these bumps did not open up and fill with white sanding dust after I sanded. Yet I sure tried to get rid of dust in the air, thinking at one point that maybe that was the problem. Hadn't mentioned it in prior posts, but ran an HPEV(?) air filter machine for a few hours before coating. (Then turned it off while working, thought maybe just the intake of air would cause more dust to rise.) But so many! More than in the photos I provided, I think, on subsequent coats.
It sure is not made clear in the CLC manual, at least for the Eastport Nesting Pram, that all this sanding is expected just to make the coating (reasonably) smooth.
This really just looks like the "First Coat Blues" that are typical of the first coat of epoxy on bare plywood. In my experience it's not bubbles but dust, fibers, and fuzz raised on the plywood. I have found the absolute fastest way to deal with this is with a freshly sharpened scraper. I concentrate on a getting a thin first coat with no drips, runs, holidays, fisheyes, etc. then let it cure to almost hard and scrape thoroughly. Do an equally careful second coat and it will be beautiful.
A question and a comment. First, you never stated what epoxy you are using and what speed of hardener. I assume that you using a slow hardener (such as MAS slow)? Regardless you might consider cooling down the room in which you are working. This will allow more time for the bubbles to pop. Also, I have found that the West System Yellow foam rollers introduce fewer bubbles than either the gray rollers that CLC sells or the white "hot dog" rollers that one can purchase at a big box store.
But from the photos it appears to me that you have filled out the weave and that it is time to start sanding. Personally, I start with 120 grit paper and then work up to 180 or 220 before varnishing. Sometimes, after sanding with 120 grit I might roll on another super thin coat of epoxy if I am not satisfied with the finish.
i have built a lot of boats and looked carefully at your pictures.
first, this looks pretty good for a rolled/brushed on coat of epoxy and i agree with djdewitt above, that i would start my sanding to smooth out the surface.
second, its not clear to me that you have micro-bubbles.....but you will know relatively quickly, if you do, when you start sanding. my impression, based on your pictures and my experience, is that these are little dust bits in the air that settled on your epoxy and are creating little rises/pimples - but not bubbles. bubbles typically show up as glass-like spheres in your epoxy - they are air filled and will reflect the light very distinctly -- they litterally look like champaign bubbles.....and i don't see that in the pictures.
when you start sanding, if it is little rises/pimples, it will sand off and you will have a nice flat surface. these rises/pimples will sand off relatively quickly and easily. if you have 'bubbles' , when you sand, you will open up the top of the bubble and the lower part of the bubble will fill with epoxy sanding dust leaving little white pin pricks (the open-dust filled bubble) all over. its a very distinctive look.
all that said, all of this is addressable with the sanding process.....and i agree....its time to start sanding.
all the other advice and your comments are good about how to avoid bubbles and get 'smoother' coats.... but the reason we all talk about the laborious and joyful process of sanding....is that the epoxy does not generally create the smoothness of finish that would satisfy anybody....hence we sand.
give it a go on the sanding and let us know what you see - and if you really have bubbles or if these are just these routine surface imperfections that you need to sand out.
