MirrorCoat Air Bubbles

[Lowespro2]

I coated a table top with mirror coat following the instructions. Did the initial seal coat, waited a full day before applying the flood coat. Applied the flood coat, spread it out with a paint brush and waited about 10 minutes. Then used a propane torch about 6inches above the surface to remove all visible air bubbles. I then walked away to let it cure. Today I went to check on it and there about a dozen or more air bubbles that created bumps on the surface. They are not large, just raised above the rest of the surface which is otherwise smooth. While I can find tons of information on systemthree’s website on how to remove air bubbles while the epoxy is still wet, I’m not having much luck finding information about how to repair bubbles in cured epoxy. The closest thing I can find is a video on sanding and polishing a damaged surface. Do any of you have any experience with fixing this issue?

 

[Craptastic]

Sanding and polishing it out is pretty much the only way.

Your mistake was that "used a propane torch about 6inches above the surface to remove all visible air bubbles. I then walked away to let it cure." That last part was what is causing your extra work now. You need to pay more attention to after the pour than that, and certainly for much longer, to be more successful. Seal coats aren't always fully sealing the surface and are mostly meant to make adhesion of the following pours occur better.

Sand it out carefully and if you are lucky you can get to the top levels of the bubbles somewhat quickly. Then a real good cleaning (blow off the dust and clean with alcohol a couple of times) before a light sealing coat of epoxy.

It's never fun to rework a top you thought was done, but in this case you must.

I've had to watch epoxy pours carefully for over 5 hours to make sure all bubbles were taken care of. It's a pain but if you want that glassy surface you will need to take the time to walk it along there.

 

[Echd]

Yeah, I did some chintzy thin blue line flag recently. I made the mistake of making the blue line deeper than needed... I was checking that thing for bubbles for about two hours. What a pain that was.

 

[Lowespro2]

Sanding and polishing it out is pretty much the only way.

Your mistake was that "used a propane torch about 6inches above the surface to remove all visible air bubbles. I then walked away to let it cure." That last part was what is causing your extra work now. You need to pay more attention to after the pour than that, and certainly for much longer, to be more successful. Seal coats aren't always fully sealing the surface and are mostly meant to make adhesion of the following pours occur better.

Sand it out carefully and if you are lucky you can get to the top levels of the bubbles somewhat quickly. Then a real good cleaning (blow off the dust and clean with alcohol a couple of times) before a light sealing coat of epoxy.

It's never fun to rework a top you thought was done, but in this case you must.

I've had to watch epoxy pours carefully for over 5 hours to make sure all bubbles were taken care of. It's a pain but if you want that glassy surface you will need to take the time to walk it along there.

Matt,
I guess I took the last line of the instruction’s to “avoid over torching because the surface can burn” too literally and thought after I had already torched the surface removing the visible bubbles that I should not torch it again because I might burn the surface.

In the manufacturers video to repair damaged areas they sand starting at 1000 grit and step up to 1500 grit, followed by applying a polishing compound with a buffer to polish it. Is all of that necessary to get rid of the dozen blisters before reapply another thin flood coat? Or can I just sand the blisters off and fill the voids while applying another thin flood coat to the entire surface?

Thanks for the advice!

 

[mike_wood]

I coated a table top with mirror coat following the instructions. Did the initial seal coat, waited a full day before applying the flood coat. Applied the flood coat, spread it out with a paint brush and waited about 10 minutes. Then used a propane torch about 6inches above the surface to remove all visible air bubbles. I then walked away to let it cure. Today I went to check on it and there about a dozen or more air bubbles that created bumps on the surface. They are not large, just raised above the rest of the surface which is otherwise smooth. While I can find tons of information on systemthree’s website on how to remove air bubbles while the epoxy is still wet, I’m not having much luck finding information about how to repair bubbles in cured epoxy. The closest thing I can find is a video on sanding and polishing a damaged surface. Do any of you have any experience with fixing this issue?

I feel your pain as I have been there. I have started spritzing denatured alcohol after initial pour to break up bubbles then go to torch later. Works for me.

 

[Craptastic]

I guess I took the last line of the instruction’s to “avoid over torching because the surface can burn” too literally and thought after I had already torched the surface removing the visible bubbles that I should not torch it again because I might burn the surface.

In the manufacturers video to repair damaged areas they sand starting at 1000 grit and step up to 1500 grit, followed by applying a polishing compound with a buffer to polish it. Is all of that necessary to get rid of the dozen blisters before reapply another thin flood coat? Or can I just sand the blisters off and fill the voids while applying another thin flood coat to the entire surface?

Maybe by "over torching" they meant getting too close or moving too slow with the heat. I have usually used a heat gun and it really doesn't take much to get them to pop.

The video sounds like it's fixing a surface that has been set for a few years and now needs some restoration. Most epoxy flood coats stay rather fluid (relatively) for the first few months and will take more coats with a seamless look with just a bit of care. Bring it up somewhere between 500 to 700 grit (mainly to minimize swirls in the sanding), make sure it's damn clean with a couple of alcohol cleanings, and give it that thin flood coat. The next coat should be watched carefully for bubbles for a few hours. And toothpicks will be your friend to help the old bubbles fill and vacate any air while they have the chance to do so.

The good news is it's likely there won't be a long watch time this time since it's only the old bubbles that may keep trying to evacuate air now.

 

[jlwest]

I have actually drilled out a few bubbles and poured a new thin top coat.