Expoxy Bubbles

Is it to cold in my basement? 58 degrees. I can sand them out, but how do I prevent them again?



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RE: Expoxy Bubbles


     Yes you can most likely sand them out.  You just need to sand enough to openup the air pockets, then you'll be able to squeegee on another coat of epoxy to fill them back in. 

     58 degrees is a bit cool, i preheat my work area to 70-75ish before i start epoxy work.  Then I slowly let it cool a bit to avoid getting any bubbles, but not too much or the epoxy won't harden.  Make sure you put on the epoxy in a very thin layer by using a plastic squeegee (credit card, milk carton, etc.)  I've found that if you work with very thin layers there's just no room for bubble to form.

 Good luck


RE: Expoxy Bubbles

If I am not mistaken you can use a heat gun over freshly layed epoxy to pop air bubbles look in "Tips for boatbuilders" to confirm.

RE: Expoxy Bubbles

On tips it states " As the temperature increased during the day, the air in the wood expanded and was forced out though your flawless coating" 

This is my third coat so I don't think that is my problem. I used a foam roller, would that cause it? Plus my basement temp is pretty constant at 58 -60

RE: Expoxy Bubbles

I agree on the need to heat your basement to 70-75. I think that will cure your problem. I am completing my second boat in my basement too. I use 2 portable heaters to raise the temp whenever I'm working with epoxy. The foam roller shouldn't cause a problem with un-thickened epoxy applied in thin layers. The epoxy is thin enough (low enough viscosity) that the small bubbles just pop on their own. 

RE: Expoxy Bubbles

     After looking at your pictures, my guess is that your foam roller was the main cause of your bubbles, probably because you were working too fast.  Try a quick experiment:  mix a small batch of epoxy, then use your normal brand of foam roller to apply the epoxy to a large scrap of ply or heavy cardboard.  Move your roller quickly over one area of scrap, and slowly over another.  Look to see if the 'slow' area has fewer or no bubbles.  If both areas have lots of bubbles, you need to use a smoother roller or slow your roller even more.  If neither area has bubbles, the hardened roller in the trash was probably at fault.  If slowing your roller doesn't help enough, try slowly tipping the epoxy with a foam brush (just like tipping varnish).

     You didn't say where you are storing your epoxy.  On your basement floor is a no-no.  If you can, move your epoxy to a warmer part of your house for a few hours before you apply a coat.  I know it can be frustrating in a cramped work space to work around a lamp(s) but a moveable light might help you see the surfaces you are coating so you can deal with potential bubbles before the epoxy sets.  Good luck.

RE: Expoxy Bubbles


thanks for advice I will try out you suggestions tonight. I definitely turn up the heat.

RE: Expoxy Bubbles

Being a contrarian, I have worked epoxy resin at about 35-40 degrees, cold enough that my fingers would get numb after about a half hour, and the epoxy takes three days to cure. I don't worry about the bubbles, they sand out and aren't noticable after a few coats of varnish.

The cold does cause a few problems, bubbles in the resin, possibly cloudiness, and the thickness of the resin makes it harder to work with. If you have the means, warmer is better.

RE: Expoxy Bubbles

There are a couple of tricks you can use here. First, although your project is quite cool, your epoxy doesn't have to be. One trick is to store your epoxy in a box with a light bulb to keep it warm. 80 degress is not too warm, although your pot life will be shorter if you're using a medium or fast hardner, so use slow hardner or mix small batches.

You can also thin the epoxy slightly with denatured alcohol to make it flow better. No more than 5 to 7% by volume or shrinkage may be a problem.

Another trick is to use a hair dryer to keep the surface and the epoxy you're working on warm, and the epoxy layer THIN as you work your way down the surface.

Warm epoxy, keep it warm with a hair dryer, and put it on thin with a squeegie works best and as the wood cools, it will suck the epoxy into the wood instead of blowing bubbles.

I hope this helps.

RE: Expoxy Bubbles

One thing I tried when my garage was cool, in addition to trying to heat the garage a little. I would put some of the epoxy into the microwave prior to mixing. I tended to mix small batches and I think I just warmed one (hardner or resin) a little.

RE: Expoxy Bubbles

I sanded of bubbles and heated epoxy and room up. Then after rolling thin coat, I tipped out with brush. Came out with beautiful shinny smooth finish, you wouldn't even know what a disaster it looked like :>).

Thanks for all your input 

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