Hundreds of tiny air bubbles in epoxy mix

Hi, people. I´m applying the fill coat in my NH. When I mix epoxy in the recipient, it appears a lot of tiny air bubbles in the mix. It´s Ok, apply it with the bubbles or I must wait until they dissapear?. How can I avoid that?
Thanks in advance

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RE: Hundreds of tiny air bubbles in epoxy mix


Don't worry about those air bubbles on a fill coat, they'll all go away when you roll on a thin coat for your fill coat. If they don't you can make them dissappear by "tipping out" the epoxy, i.e., take a 2" foam brush and drag it lightly over the surface before the epoxy sets. You'll end up with a smooth coat. The bubbles get in the mix due to over-zealous mixing. I use a 1/4" dowel with 4 1" drywall screws in it chucked in a drill and it's not unusual to get bubbles. Never been a problem. If you wait till they all dissappear in the pot before use you're going to have a lot of pot hardened epoxy on your hands!

George K

cautionary tale

George could be right - if you really can get all of the bubbles out.  I had an issue with my CH16.  It is isolated around the hatches, where I dis small epoxy sessions sanding and filling.  Everything had cured for over a week.  I took the boat out into the sun.  When I brought it back in, there were pock marks on and around the hatches.  These were 3/32" or so little raised bumps inside the weave in some areas.  My guess is that they were caused by air bubbles in the epoxy when mixed and/or contamination of the surface prior to application of additional coats (I do not think this happenned on the initial wet-out, as I wetted out the whole deck at once and this condition only occurred around the hatches where I applied a small batch).  I have been out paddling the boat and have not yet tried to sand and repair the bubbles.

Anyone else encounter this?

Paul in Phoenix 



RE: Hundreds of tiny air bubbles in epoxy mix

George. I follow your advice. Almost all bubbles are gone, as you said.

Some bad photos in

Could you give a look to those and give me an advice about how it looks?. It seems to be not as smooth as it could be. I´m in doubt about a) wait it cures and sand it to smooth it or b) apply another fill coat and sand it after that. What your experience says?

I have no experience on this but it sounds difficult to me that raised bumps "inside" the weave are caused by the fill coat. It seems to be poor adherence near de hatches due to excess of squeeging, for example. May be, when you moved the kayak that zone suffred an imperceptible torsion and react in this form. Or may be, after a week your first coat not cured perfectly around the hatches and outgassing occurs due direct sun exposition. 

Thanks everybody.

RE: Hundreds of tiny air bubbles in epoxy mix


In pictures 4-8 it looks like the cloth didn't get fully saturated when you did the wet out. If you have fill coats on those portions and it still looks like the cloth is white you should sand those parts off carefully, place another layer of cloth on those areas and wet it out again. You'll have to feather in the edges of the patches but they will not be visible when the boat is done. However, if the pictures are deceiving and the cloth has disappeared under the fill coats you're doing fine. As far as the smoothness is concerned, it looks like you have plenty of epoxy on the boat right now and you should start smoothing it out. Be sure not to sand into the cloth. You'll end up with a light-greyish, even surface. If you don't have that look and the cloth is starting to show, roll on another thin layer of epoxy and sand again.

Looks good so far. Fun building inside, huh? You might want to move it back outside for sanding as it will create a bunch of the stuff! And don't forget to wear a dust mask when you're sanding epoxy. It's some pretty nasty stuff in dust form.

George K 

RE: Hundreds of tiny air bubbles in epoxy mix

Thanks George. And you are right again, pictures 4-8 are related to a previous problem because excess of squeeging in in a small area of my bow and resolved thanks to this forum too. In that case I followed the advices and chose to replace the fiberglass as shown in pictures 9-10.
I did de fill coat inside because here in Argentina we have -1° C now and epoxy doesn´t want cure outside. My garage have only one wall. My wife has understood that and allowed me to close the living room until the epoxy cure. After that, kayak and Ivan will go the cold outside. But it's worth, I think.
Thanks a lot.


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