Epoxy resin and eliminating bubbles

[deniseO30]

Is the substrate warming up from the sun and outgassing? (air and or water vapor would make bubbles) that's a problem with fiberglass in general.. it holds that moisture until it's very warm. the epoxy is not going breath so the air (outgas) will bubble through it. Maybe if you try applying the epoxy when the temp is dropping instead of rising you may get less bubbles. just thinking aloud...

[mitiempo]

Sounds like you are getting out gassing from the surface you are putting the epoxy on. Warm the surface first with a heat gun before applying and it should eliminate the problem.

[Irunbird]

Thanks, Brian- that sounds like the closest thing that makes sense. I am doing this in the morning, shortly after the deck area has dried from last nights' dew.. so it probably is pretty cool. I'll heat it up next time and see what happens.

[deniseO30]

Kicks Brian in the shins

"Maybe if you try applying the epoxy when the temp is dropping instead of rising you may get less bubbles. "

"Warm the surface first with a heat gun before applying and it should eliminate the problem. " = meaning as the temp drops.

[deniseO30]

Just loathes being invisable

[Irunbird]

Sorry, Denise- you get first credit. But, as the temp drops, I'm sipping a martini, not working on my boat!

[deniseO30]

You go! .

[TQA]

This will work with thinner mixes don't know about the thick.

Apply as normal. Using one of these small pencil butane blow torches gently heat up any bubbles. They pop and the surface clears. Repeat if required.

Done this many times with no probs but have an extinquisher to hand.

[travlineasy]

Now you're gonna' think this sounds nutty as Hell, and I've never used West System to try this out, but it worked extremely well with several, clear, epoxy resins I've used years ago.

In the late 1980s I used to make some really neat tables from slabs of black walnut, most measuring 7 to 8 feet long and 18 to 24 inches wide. The walnut was sanded with 400-grit wet/dry automotive sand paper, vacuumed, then tack-ragged to remove the tiniest particles, which is imperative.

The epoxy resin was then mixed, poured on the table's surface, and squeegeed to an even consistency on the entire top. Within a few minutes, bubbles began rising to the surface, thousands of them. The next step, which the first time I did this scared the hell out of me, was to fire up a propane torch and play the flame lightly over the surface. Each and every bubble popped, the finish layed down flat, no dimples were created and the surface dried bubble free. The guy that taught me how to do this said what occurs is the bubble quickly expands and pops before the epoxy is anywhere close to being cured.

I'm not sure if West System is flammable, therefore I would suggest trying this on a small patch of metal or fiberglass somewhere where it's safe to test. If it is, the technique may still work using a heat gun, but I've never tried using one for this purpose.

I don't believe heating the surface prior to applying the paint will do anything, but it may be worth a try, again on a small test strip of fiberglass or metal.

Hope this helps,

Gary

[Stumble]

Epoxy is Highly flamable, and very toxic while burning. And you cannot use water to extinguish it, or it kicks off highly dangerous fumes.

The general recomendation is to first seal the substrate with unthickened neat epoxy. Just a very thin layer just to seal the surface, then come back with the thickened filleting mix. As mentioned the likely problem is from out gassing from the surface. Worrying about surface temprature is just going to cause other problems, like accelerating the kick of the epoxy.

When dealing with very large quantities of epoxy for infusion, it is typical to degass it by applying a vacume, but that it pretty extreme for simple filets.


If you are using slow hardner already, and you need an even slower open time, try storing the resin and hardner in a cool fridge. Something around 60 degrees is ideal. To cold and it can thicken and be hard to mix, it will still kick, but you may need to let it warm up a little before working it. And don't move it directly from a fridge to outside air, if it's to cold water can condense in it, and cause other problems.

You can also switch to West 209 (it's what I use in New Orleans). It will give you about 45 minutes to an hour working time, but it will take a while to cure (about a day).