I mix either GP or BSI epoxy (30 min) in those little GP mixing cups and there are so many air bubbles. Is this ok or normal.

I have noticed that I can see the bubbles in the epoxy of the wing joint when it cures and they are visible. I would assume this makes a less than ideal joint. Am I worrying about nothing?? Or am I doing something wrong?

I normally get more bubbles when I stir too fast. Try stirring very slowly. 20-30 secs stir is all you need. I use a vacuum chamber for get rid of bubbles in epoxy potting compound for metallurgical sample preparation in my lab but this is not necessary here. A small amount of bubble doesn't matter.

Warm air will get rid of the bubbles almost instantly. Even your warm breath will do it. Can't remember where I learned that trick but it works. Try it!

Possible, as higher temp will lower the epoxy viscosity and bubbles will tend to travel to the surface faster. Well, try to prevent it first. Word of caution though, with higher temp, the curing time is shortened.........

Be advised...I'm not talking about using the heat gun on it. Just raising the temp a very few degrees...Like I said, even breathing on it will do the trick (That is, in fact, how I do it). I don't think that's going to radically alter your curing time.
I remember now where I learned it. Breathing on the mix is the accepted way of removing bubbles from the two part epoxy used for encapsulating coins and such in paperweights, coating bar tops etc. Envirotex is one name brand. I use it for laying fg cloth as per Dan Parson's instructions.

I believe it has to do with the gas (carbon dioxide) from your breath. I used a special epoxy on a train layout for fake water once, the instructions were to breath on it as it cured or to use a butane torch waved above the epoxy to draw out the bubbles. Not the heat, but the gas from the flame (same as exhaling) is what does the trick.

worth a try. any scientific explanation or basis for this ?

I did some of those Cypress tables many moons ago and the instructions on the epoxy called for a gentle pass with a hair dryer to get the bubbles out. The heat expands the bubble I also agree that the viscosity is affected. Try it. Pete

During a class i took on composite aircraft repair (full size planes) I was told to always let resins sit for a few minutes to let the bubbles come to the top. We always used slow curing resins so you had the time to do so, you dont have enough time with 6 or really even 15 minute epoxy. For me, if anything is important enough to worry about bubbles, i am going to be using 30 minute or slower epoxy anyway, so i just let it un-bubble itself.

[QUOTE]Originally posted by FlyingPilgrim
[B]I believe it has to do with the gas (carbon dioxide) from your breath. I used a special epoxy on a train layout for fake water once, the instructions were to breath on it as it cured or to use a butane torch waved above the epoxy to draw out the bubbles. Not the heat, but the gas from the flame (same as exhaling) is

pilrim did you say torch. could you sow us an example of how to do this .is your lab still there,some one call the fire dpt.
I wonder if the AMA will cover this one.
:stupid: just finning with ya
crash 141

Rich, it sounds crazy, but it did work (on this stuff, anyway!) No doubt be carefull if anyone tries this!! On the train layout I did this on, it was all open, no (major) fire hazards.

I just waterproofed the inside of a Dumas Chris Craft boat with thinned epoxy, and bubbles were popping up all over. I was huffing and puffing on it to see if the "hot breath" method worked with regular epoxy (Bob Smith 30 min thinned w/ alcohol). Either it really did work, or it merely seemed to since I was high from inhaling the alcohol fumes with a combination of hyperventilation!