I have tried every technique I could find but I still get tiny bubbles after stirring my epoxy. I am in the “2 to 3 coats of epoxy to the entire boat” stage of my Eastport Pram. I did the interior of the bow, using what I thought were normal-thickness 3 coats (roller and tipping with foam brush) and the roughness, drips, etc. make it look like a kindergartner’s fingerpainting job. So am I supposed to sand this harshly with a random orbital sander, 80 grit as I’ve seen in other posts, to smooth it down? I am afraid I would sand it down to wood. Second part, the stern, I tried using super-thin coats, such that I essentially applied the epoxy and wiped it off. The roughness is still there but possibly due to other issues like wood grain rising and brush marks. Should I sand this coat down, I am assuming with 120 grit? In one other old post I saw that an answer was that you can either sand after each coat or wait until the end, but the sanding of each coat will make the actual sanding easier to do. At least that way, there should be fewer thick places and drips, I guess.
Welcome to the not so fun part of epoxy plywood boat building. Here’s where the slow hardening varieties of epoxy are good. If only to give you time to let the pot of mixed epoxy sit for a few minutes to let some of the air bubbles work their way out. Here’s where warmer working temps but not hot helps. The thinner the epoxy the easier the bubbles release.
I have yet to really solve the art of getting a good coat without any sags. I only aspire to having smaller sags. I am a proponent of sanding between coats. And unless I have big blobs to carve off I don’t go coarser than 120 grit. And I wait until the epoxy is fully cured before thinking about sanding. So it’s a multi day affair for me.
Hi Nancy,
i was reading you post and wanted to share a couple ideas.
first, its really not a problem if you have tiny bubbles in your epoxy after mixing. what matters is if you have tiny bubbles in your epoxy coat after applying it to the surface/wood. usually, the rolling and tipping will get rid of bubbles in the surface. so if you are not seeing bubbles in your cured epoxy after application…don’t worry about that. if you are seeing bubbles in the surface, Robert’s points above are well taken. also, you should ensure, whenever applying epoxy to bare wood that the wood is in a cooling phase (getting colder) and not getting hotter which causes ‘outgassing’ or basically the wood is blowing bubbles into your finish.
second, the first coat of epoxy will often raise the graing and result in a less than perfect surface. so i usually am very spartan in my first coat of eppxy becuase i am just sealing things up. drips and runs to be avoided. after that first coat, i will do a light sanding with no harsher grit than 120 grit to have surface where i have taken all the wood roughness off. what i mean by this is if i gently sweep my hand over the surface, nothing that is snagging my skin.
on subseqent coats, i typically am not agressive in sanding unless i have to take a run or sag out. otherwise you just are going backwards.
the other tool i use is a squeegee for epoxy application on bare wood with some follow-up with tipping with a brush. the squeegee can be used after rolling or as a roller alternative, but tends to be really good helping to minimize runs and sags.
h
Thank you Robert and Howard! Sorry I did not reply sooner; I was busy sanding (I am sure you know the feeling). Your comments and suggestions were very helpful. And, Howard, I ordered a squeegee which is supposed to arrive today!