Using propane torch to remove barrier coat bubbles?

[JeremyFowler]

How to get rid of the bubbles that appear after applying with a roller? I’ve put on 3 coats of West System epoxy 105/206 (with black pigment to make it UV proof and more like paint) but a multitude of bubbles appear just as the epoxy is setting, and the next coat does not fill the little hole left by the bubble.
I’ve now sanded the bottom again, to provide a key, and I have built up enough courage to try again. I aim to put on another couple of layers. I hear conflicting stories about the additive 422 so I’ve not used it on the first layers.

I’ve got a propane torch, apparently torching over the surface straight after rolling will remove the bubbles?

Does anyone have first-hand experience with this that they will share please?

[mlydon]

Switch to barrier coat paint - interlux 2000e - no bubbles, and it’s made for the job. Why are you worried about UV on your bottom. It will never see the sun…..
Put bottom paint on over it.

If you are looking to do this on a little boat like your dink that spends a lot of time dry, paint it with a linear urethane like awlgrip, perfection, or an epoxy paint of your choice.

Whether you are intent on continuing with west, or switch to paint, or whatever, you roll and tip to knock down roller bubbles - drag a brush across the wet area after each roller load.

There’s a million articles and YouTube’s on rolling & tipping…..works great

Ps - if the subject is dark and the sun’s on it, that can cause gassing too - best to do the shady side and wait for the sun to move , or do a small project under cover.

Good luck on your project,

Matt

[GordMay]

From West Systems ➥ https://www.westsystem.com/instructi...r-faq/#bubbles

WHY ARE THERE BUBBLES IN MY EPOXY COATING?

Air Is entrapped trapped in the epoxy coating. Air can easily escapes in the epoxy as the temperature of the epoxied surface rises. This is called outgassing.

A. To prevent outgassing, coat wood with epoxy as the temperature is dropping—after warming the wood with heaters or during the later part of the day.

B. Apply a thinner epoxy coat, allowing air to escape easier.

C. Tip-off the epoxy coating with a roller cover brush to break bubbles.
See Barrier Coating ➥ https://www.westsystem.com/instructi...rrier-coating/

D. See Out-Gassing caution in Epoxy Chemistry, or read more about bubble-free coating at Epoxyworks.com.
➥ https://www.westsystem.com/instructi...oxy-chemistry/
➥ https://www.epoxyworks.com/index.php...epoxy-coating/

[tkeithlu]

I think that I would avoid the propane torch if at all possible, having tried the approaches Gord has laid out for you. Torches produce a very concentrated heat that can very quickly result in damage if not fire. If heat is needed, I suggest you try a heat gun first.

Good luck with it.

[Spot]

I had an epoxy-used-as-paint finish over plywood go bad on me. The plywood underneath moved and cracked the epoxy, allowing water in which accelerated the cracking and moving process. Areas that were glassed did better but the veneers still wick and my damage is widespread, even where there is no direct sunlight or moisture. Had I covered the boat and/or painted it I could have avoided much the now-looming refinishing process. My composites supplier is a boat guy and he finished the bottom of his wood boat with a layer of epoxy followed by oil-based 'tractor' paint. He says he has 15 years on the paint with no issues.

All of this to say don't use epoxy where you need to use paint.

[Spot]

PS It's not that I have NOT seen it done, the torch thing: for thick epoxy on bar tops and for fillets on wooden casting patterns. I just wonder how effective it would be on a thin film like a barrier coat or if it would aggravate the bubble mechanism. When I was doing more epoxy glassing I would either go first thing in the morning or wait for falling temperatures in the afternoon especially before doing fill coats. My incident with the plywood boat may have some special causes not related to Jeremy's project.
Is there time to run a test panel?