Eric S

I'm not a pro painter.

While prepping a house for the job I found bubbles on the walls where the paint never did stick or stopped sticking. I don't know which.

The technical term is blistering?

About the walls:
-Both are on sides of the house as opposed to front/back.
-These areas get no sun because of the eaves and the extended roof.
-At least six previous layers of paint on one side and four on the other.
-All blisters were at or near the top of the walls.
-The walls are wood siding that is vertical and about 4" wide with 90 degree groves between each panel.

Q: What would cause blistering in this particular situation?

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"One time I bought some used paint...It was in the shape of a house." -Steven Wright

lxdollarsxl

my guess without seeing it would be moisture in the timber.

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Damned if im gonna do it more than once.

Brushslingers

Damn good guess Dollar.. i'd say the same thing except.. how old is the house? You said 7 or more coats of paint... how do you know this? bare wood showing? Could be lead oil peeling off. Could be latex over oil without proper primer, blistering where there is the most moisture.... Need a picture, however... run up a ladder to the blistering areas and rub as hard as you can with a finger... does the paint come off or not?

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Benn

Eric S

I agree with Dollar too.

That wood probably has areas that never dried out.

"run up a ladder and rub it too see if it will come off." ...I've already removed every instance by using a 5-in-1 tool. I would cut the blister, get the tool under the surface and remove paint which was not sticking. It's not that bad as to where I could remove it by rubbing it...there was only one small area like that. You might have been thinking about rotted wood with a coat on top of it?

How did I know there are 6-7 coats?
I see after sanding perimeter areas:
bare wood
pink paint (primer?)
One light then one darker coat of yellow
blue
and last the San Francisco Fog
OK just 5.

Somebody obviously did some patching up work too.

I'll take some now and after pics of house and re-post when complete.

__________________
"One time I bought some used paint...It was in the shape of a house." -Steven Wright

Brushslingers

Naaa, I asked because if someone paints latex over oil without priming, the topcoat will bubble and rub right off with your thumb.

Prolly just wet wood, but... 5 coats of paint.. should have been dry by now, different colors... can't see it but, may be something else going on.

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Benn

Eric S

I'll be painting latex over Duron's Stain Killer. It says it acts as a Stain killer and primer. I used it to cover up bare wood spots. Will I need to paint a primer on top of those areas?

"Can't see it but, maybe something else going on."

Could there be deposits in the wood that paint won't stick to?

What seems related is that the blisters in question were such that none of the coats of paint were sticking. By cutting through the blister with 5-in-1 tool, I was getting through all of the layers.

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"One time I bought some used paint...It was in the shape of a house." -Steven Wright

Brushslingers

I opened a thread, and couldn't figure out how to say what I was trying to say... posted two pics on it. Thread is called "disturbed", does your paint blister sorta look like those two pics?

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Benn

Eric S

Brushslingers/Benn:

No. The blisters are different in shape (like bubbles). These bubbles are not perfect circles rather, they are usually starting near the tops of the panels or near things that are difficult to paint around as in things you would rather move out of the way to paint walls. In every instance so far these bubbles have been closed (no open point in it). Hence me finding them and opening them up with the 5n1.

Also in the pics mentioned by you, the blisters seem to be paint that has peeled away from wall...unless those pics show the after a little prep result. I don't think that is the case.

Too bad they don't make disposable digital cameras...I'd like to post this house's walls to show.

Please pardon my late responses. I go to the Inet about once a day.

George Z:

Thanks for posting the eco paint related website. Have breezed through and will be hanging out there often to learn more about Painting.

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"One time I bought some used paint...It was in the shape of a house." -Steven Wright

Brushslingers

The pics I posted was classic lead paint with a solvent primer. If thats not what you seeing then I would have to say pure moisture. Hard to tell without actually seeing it, and they do make disposable digitals now BUT, sounds like your on the right track with your primer.. so all should be good.

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Benn

Joewho

Bubbling. Sounds like it's the area under the soffit and always shielded from the sun. My vote goes to the moisture comment.

Eric S

Last two posts resonate with me. No sun and moisture content.

They DO sell digisposals huh? Good to know

Thirty % chance rain on Saturday and Sunday. I paint on the weekends. Worth it to chance a coat especially on less exposed areas during the days? Looks like it's sposed to rain starting eves/nights.

__________________
"One time I bought some used paint...It was in the shape of a house." -Steven Wright

Eric S

Brushslingers:

About disturbed. Today I went to work prepping that wall in question and realized what a closer look is worth. This does look like that situation.

A solvent (oil base?) would not stick well to a lead base paint?

The first coat on the wood is something between a pink or a red.

__________________
"One time I bought some used paint...It was in the shape of a house." -Steven Wright

Brushslingers

Sorry Eric, this new "saved" cat is driving me insane, hard to even type with it's constant bashing its head into my hands... ha.

Does the bare wood show? See in the.. lesse, 1910's to about 1957 or so, they used kerosine or solvents to "prime" the raw wood, and then used 5 inch brushes and lead ingrained oil paint to do the work. So if it flakes like that, and you see the non-rotten bare wood underneath... you are most likely facing a solvent soaked wood. Normal latex primers WILL NOT SEAL this problem, causing blister bubbles filled with water. You will have to use an oil based bonding primer that is rated to adhere to solvents or, shellac.... then follow with an oil based primer and hope that the rest of the wood doesn't finally "dry" out. Funny thing is, those guys had it right, how many homes from the 40's have you seen that actually needed outside wood repairs? Sure the paint ends up falling off but that wood... heh.

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Benn

Eric S

Brushslingers:

You gotta like the cats that want attention more than the ones who ignore you and keep on typing...argh!

I noticed that this wall I'm working on has had far more blistering over the years than the one on the other side. Scraping and then coverage without sanding obviously had occured over alot of the wall area.

In the areas where the current blisters are I am using Durons Stain Kill after I have sanded to bare wood and then will be covering with a latex. In any event if this does not work it will be a moot point as we are trying mainly to cover this home before the winter sets in for preservation of the wood panels. This house was starting to develope a need to be re-painted.

This particular wall has been so incorrectly done over the years that we realized it would need to be totally redone to be right. This would be quite a project and as I'm painting during weekends only there won't be enough time to completely redo it.

We both know that the wall needs to be redone to be at it's best but, that is not what Mom wants right now.

The top coat seems to be shiny compared to the other side. I'm thinking that It might be good to lightly sand it since the topcoat will be latex.

__________________
"One time I bought some used paint...It was in the shape of a house." -Steven Wright