Paint Not Bonding To Surface...why??

lornmastro

Had a situation last week that i was hoping you veterans could help me figure out. Had to paint some wainscott molding/trim so first checked it with denatured alcohol the paint came off so it wasn't oil. Sanded down the surface and painted with BM semi gloss paint. Did a scratch test...scatched off bad. So I ended up priming with BM fresh start and painting with semi gloss. My question is what could have caused a bonding problem like that and do you always do a scatch test spot to precheck for bonding when painting trim??

DeanV

How long did you let the semi-gloss dry when you checked for adhesion? BM seems to take a lot longer than other paints to develop its full adhesion.

slickshift

Well I doubt that you didn't sand enough (or at all)
I can't see you doing that...lol
However, it could have actually been oil, but so "worn" that it came off on the rag
You could have revealed a layer of oil after sanding, enough newer stuff so it didn't slide off, enough older stuff to affect the adhesion
The surface could have been contaminated (especially if it was a bathroom)

Are any of these possible?
Was the paint on the test rag more like pigmented dust or was it runny?
How much/far did you sand?
Was it in a bathroom?

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Originally Posted by ModernStyle I have never used this crap before and I pray to the paint gods that I never have to use it again, I would rather use Behr

lornmastro

To answer both of your questions. Yes I let the semi gloss dry for 2 days before I checked it. The area was a front foyer.Yes I did sand well slick but you might be hitting on something...When I did the denatured alcohol test the paint did come off my rag but not alot of it like what i have gotten when checked previously and it was latex.I almost thought that maybe they had did one layer of latex over oil. Also a previous painter(yrs ago) had painted the risers white over this mystery paint and when we went to sand the risers the white paint was coming off the mystery paint badly....bad bonding for that paint as well. So when doing a denature alcohol test on oil are there times where the paint comes off....slick do you think this was actually oil paint? I know that there have been many discussions here about latex over oil and I'm really not too comfortable with that and normally will put oil primer or oil paint over oil paint. Will I get a good bond with latex over oil...I think not! Or how about a GOOD bond with BM fresh start over oil?? Thanks all for your input!!

slickshift

There are times when the 'pigment' of oil comes out on the rag test
I'm not sure that's the proper term, but it's like the oil paint is worn and almost (or actually) chalky, and the color that shows up on the rag is more like chalk dust that's now wet with solvent rather than latex paint wiping off
It's subtle, yes, and I'm not sure I'm explaining it properly
But oil can come off in the denatured alcohol test that way, and give the appearance (color on rag) of latex

True, many have gone right over oil with latex
Sometimes it works
My point is, sometimes it doesn't
And sometimes it does, but won't pass the scratch test a week later

Which Fresh Start are you thinking?

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Originally Posted by ModernStyle I have never used this crap before and I pray to the paint gods that I never have to use it again, I would rather use Behr

lornmastro

When I do a denatured alcohol check on latex paint the paint almost gets clumping or gookie(gookie is that a real term??). This was different it was coming off the rag but had to be rubbed harder and didn't get gookie. I knew something wasn't right just didn't know what!!!! Thanks for clearing that up slick. Now the fresh start I used was Benjamin Moores acrylic all purpose primer. Will a latex primer provide a good bond on a oil paint?? I usually use an oil primer on oil based paint because I thought it would provide a better bond?? True or false?? thanks lorna

slickshift

Yes, you really want to use an oil-based primer in that case
The Fresh Start comes in oil (alkyd) also

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Originally Posted by ModernStyle I have never used this crap before and I pray to the paint gods that I never have to use it again, I would rather use Behr

lornmastro

yiks thats what i thought....the guy from the bm paint store said you could use a latex primer on an oil based paint. will be there tomorrow will try and sneak do a scatch test and see what happens. thanks soooooooooooo much slick!!! once again you are the best!!!

slickshift

Well you c a n ....
You can also use finger paint...lol...

Heads Up
The BM reps are now saying you can use Fresh Start latex for everything including Formica (I believe the exact words are "It's rated for use on Formica" or some such)
I'm skeptical, but to be fair I haven't tested it

I figure it's a precursor to discontinuing the oil/alkyd primers and a "You Can Say That...." sales line filtering down from the company brass

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Originally Posted by ModernStyle I have never used this crap before and I pray to the paint gods that I never have to use it again, I would rather use Behr

slickshift

...and it can take a week to cure well enough to truly prove itself in the scratch test

If it's really bad after a few days (falls off when scratched lightly), it probably won't pass the test after a week of curing

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Originally Posted by ModernStyle I have never used this crap before and I pray to the paint gods that I never have to use it again, I would rather use Behr

lornmastro

thanks slick....I think i'll buy a vat of oil primer lol