HELP!!! Bubbles in my acrylic finish.

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Forum topic by Woodbear posted 08-04-2010 03:48 AM 2904 views 0 times favorited 6 replies Add to Favorites Watch
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84 posts in 3542 days

08-04-2010 03:48 AM

Topic tags/keywords: question tip trick finishing cedar

I’ve built two of these shelves for a friend of mine who owns an Espresso Stand. Since the shelves will be mounted outside I thaought a good finish would be acrylic. And for the most part it looks pretty nice. Except for the fact that near the end of the curing of the acrylic, the cedar wood released a buch of bubble that I could not make go away with the torch. the one I tried ended up in a big lump.

My question is to anyone who has had this problem. Is there a way to sand this type of finish and repair it to the clear sheen that it should be? Or do I need to start all over?

Hind sight tells me I should have sealed the would with a sealer before putting the acrylic on. But that usually the way I do things. Do it once, or twice, or three times, then do it right.

Any input?

-- The safest place to be is within the will of God. God Bless. Michael

6 replies so far

View Karson's profile


35197 posts in 4876 days

#1 posted 08-04-2010 04:08 AM

Looks like a real problem. You could sand it flat using wet and dry paper (wet) and then see how bad it is once you get it leveled.

-- I've been blessed with a father who liked to tinker in wood, and a wife who lets me tinker in wood. Appomattox Virginia [email protected]

View skleist's profile


6 posts in 3844 days

#2 posted 08-04-2010 04:35 AM

It looks like to me that maybe there was some wax or oil on the wood that causes fish eyes in the finish.You should be able to sand,clean and refinish the shelve.

-- Shawn,Minnesota

View Woodbear's profile


84 posts in 3542 days

#3 posted 08-04-2010 05:55 AM

I guess I should explain that acrylic is a two part finish. Resin and hardener mixed in equal parts. The stirring process creates bubbles. The bubbles can be removed by running a torch over the acrylic which brings them to the top and pops them and the wet acrylic re-levels itself. But once it sets up it cannot be done that way. The bubbles were not caused by wax or anything like that. The boards were clean boards which I resawed myself and had no finish on them before the acrylic. The bubbles came from within the cedar boards. I like the idea of wet sanding. I’ll give it a try. Worst that can happen is I’ll screw it up more and have to start over.

Thanks for the input.

-- The safest place to be is within the will of God. God Bless. Michael

View tyskkvinna's profile


1310 posts in 3462 days

#4 posted 08-04-2010 05:32 PM

Typically with this kind of finish you should be able to sand it fairly smooth and then re-apply finish over it, and the two layers will blend. I just did this with some bubbles and you can’t see them ..

Definitely wet sand it and see what happens.

-- Lis - Michigan - -

View bill1352's profile


130 posts in 3597 days

#5 posted 08-06-2010 02:56 PM

That doesn’t look like bubbles, that looks like something splattering on it. I’ve done it 3 times to acrylic finishes. you might have been a few ft away & used some liquid & tiny specks went airborne. It could have been a few hours after you poured the coat. Sand it sort of smooth, you dont need to be fancy & recoat. make a tent to cover it. use a heat gun instead of a torch if you have one. The blowing air added to the heat brings up the bubbles faster & you end up with less final little dimples. Make sure you aim it away & let it run & heat up. This burns off any dust inside the burner. if you use the stuff again, go to the dollar store & get a $1 squeege, it is just the right stiffness, mix about 1 ounce, you dont need much, just enough to wet the full surface, spread that over the project & let it dry, about 6 hours. any other sealer & you should wait a few days for it to cure. It has these instructions on most packages & I’ve found that it helps the first coat greatly. I’ve put it on about 20 table tops.

-- Keep Your Stick On The Ice

View Woodbear's profile


84 posts in 3542 days

#6 posted 08-09-2010 04:59 AM

Hey bill, I appreciate your comments. They are definitely bubbles, but I did also have a couple of small strands of lint or something that got into the acrylic. I just finished wet sanding it down to 1500 grit wetdry paper. Now though I have a very dull sheen to the whole thing. I tried to use propane torch to polish it but maybe it is to thin. I’m wondering if putting another thin coat on the project will shine it up or will it just bring out the dull sheen more? We’ll see. Thanks again.

-- The safest place to be is within the will of God. God Bless. Michael

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