Bubbles When Taping Over Painted Surface?

theworx

Hi guys, I have been looking for some previous posts where it was suggested putting dish soap in your mud to prevent bubbling when taping. Haven't found them. I do a lot of work where I add on walls to previously painted surfaces which have to be taped. No matter what we do they get those little bubbles in the mud on the previously painted drywall (we call them "fish eyes"). Does the soap thing work?? And, how much do you use??

IHI

I know what your saying, we get them with both bucket and hot mud. Typically I use hot mud since most of my stuff is patch and blending and depending on seting time I let it get stiff but not hard which is usually enough time for the bubbles to appear and once it's stiff you can run your knife over it -much like knockdown- and it'll pop them leaving behind pock marks that will be filled with the next or final coat.

Curious to see if there is a preventative method to stop it from happening at all.

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theworx

IHI, I find that even the final coat will still allow bubbles to form. It's so hard to coat those little wholes without trapping air under your mud. Usually leave for the painters that have to stoke it in all directions after priming to fix it. Unfortunately, half the time I'm the painter so I agree, if we can prevent it right off the bat, it would be be a great time saver.

Where are you guys that posted the advice earlier ???

painterman

On the last drywall job I did I add DW soap. Just a big squirt to about 1/2 a large pail. Did not have any bubbles at all. I have heard of doing this many years ago and finally tried it and liked it.

Stan

JustaFramer

Wet sanding is your friend.

theworx

So this worked for you. Any difference in how it applied???

theworx

Not really off topic, but kinda funny. I told the guy I work with about posting about the dish soap thing. He said: "Yeah just watch one of the jokers tell you to add two full bottles to a pail with extra water and mix like crazy." We had a great laugh thinking about all the suds just pouring out of the top of the bucket... Really, that would be a good one ...

painterman

Worked for me just fine. Applied just the same.

Joetaper

Seems to me the gloss level of the paint you're coating over plays the biggest factor in the amount of bubbles you get. Over flat or eggshell paint finishes I have had some luck with dishsoap, but when trying to coat over satin or high-gloss nothing seems to totally take them away. Around here (Midwest) we have a product called "No-Pock!" that you can add to your mud, specifically for reducing air bubbles. I like to use it on my finish coat, it does help, but seems to be about the same as dishsoap. Ever get the taste of the soap in your mouth while sanding? About the only reason I use "No-Pock!" instead of dishsoap.

Ohio Drywall

A little soap takes all air bubbles out.Try some in your durobond.

Tom R

I'm one of the ones that promotes the soap, - - but I'm unaware of it helping to take the bubbles out (not saying it doesn't), - - I use it because it somewhat dilutes the mix, makes it easier to mix-up, makes it more slippery, and over-all just eases your application.

The best way I know to keep the bubbles out are to make sure your compound is mixed thoroughly, - - and try to run your knife in 'one-direction-only' as much as possible.

I was able to keep the bubbles out with these two steps long before I even started adding the soap.

Tom R

Sorry, worx, - - just 're-read' and realize you're talking mainly about 'painted' surfaces.

Hey, how was I to know?? Just cuz it was in the title??

Doh!!

Guess I better just stick to threatening people!!

krobinson

We have always had bubble or fisheye problems when finishing over painted surfaces (or tieing into existing painted areas). Have to agree with the "sheen" of the paint playing a part in the problem (more gloss = more bubbles).

We have simply yielded to that fact as no amount of soap or "no pock" seems to eliminate the problem. The best way we have found to deal with it is skim coat the bubbled areas after the primer is on.

Kim

Roc-It! Drywall

Worx........The info you're looking for is on page 2 of 10, under the heading "all-purpose vs lightweight compounds"

Roc-It! Drywall

The dishsoap thing does work......just don't have an exact amount to use. I've tried different amounts with different compounds and MOST of the time the results are good. I have also tried "no-pock" .I guess I'm not the only one who likes the taste of no-pock better!

DaveH

Sometimes bubbles occur when there is excess dust on the wall.

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Frankawitz

Well guys I have been doing repair work for 27 years and you can use all the soap or pock stuff you want. the thing is that what is going on the mud as it drys has no way for the moisture to penetrate the painted surface so in turn the air that is traped will raise to the surface which in turn causes little bubbles, if you sand the painted surface to break the paint you may find it helps, another thing is that when you basecoat or skimcoat over painted surface the mud will not bond, if you go back after everything is dryed and take a knife and dig into the repair alot of times the mud will pop right off the ceiling or wall.
just my two cents. as for adding soap I wouldn't waste my time or money, unless you have dry hands, then add pamolive, "you know your soaking in it!" LOL.

theworx

Ok. Thanx for your posts guys. Have tried the soap thing and it helps reduce the little bubbles but dose not totally eliminate them. The soap in the mud makes it easy to apply (Damn, Tom is right again) and personally I love the lemon fresh scent (especially when sanding) !!!

maj

Sorry to burst everyones bubble (pun intended), but Frank is dead on correct. The soap may help make the mud smoother and easier to apply, but it is the glossy painted surface not allowing the water to soak in, thus trying to evaporate out the other way causing the bubbles. The best way is to sand (coarsely) the painted surface first, the rougher the better. It will absolutely help with adhesion too.

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ricpacer69

I also agree with Frank. This is the only way that we have ever done it. I only like "Tiny bubbles in the wine" .

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