Page 1 of 2 12 LastLast
Results 1 to 15 of 16

Thread: Latex over Oil : A Hard Lesson Learned

  1. #1
    Join Date
    Dec 2005
    Location
    London, Ont., Canada
    Posts
    2,200

    Latex over Oil : A Hard Lesson Learned

    Art Mulder / April 2006


    I’ve been a homeowner for over 10 years, and have done a fair bit of painting over that time. So I thought that I pretty much had this room-painting gig figured out.


    About five-seven years ago I painted a bedroom with a light blue oil paint. Ordinarily, I would not touch oil, however this was a 90% full can that had been left by the previous owner. So I thought that this was a good way to use up the paint. (That was a big mistake. The room was unlivable for 10 days after due to the odour. Never again. It was also a big mistake for another reason. Read on...)


    Now came the time to paint again. This is a kids room, and we decided to paint some broad (14” wide) vertical stripes. So my wife washed down the walls with TSP. Then we painted two coats of CIL satin paint (medium blue) as a base colour. After a day we measured, marked, and put up green painter’s tape to mark off the stripes. Then we painted two coats of darker blue for the stripes.


    Already we noticed a few problems. While measuring for the stripes, the tape measure left a scratch on the base colour that scraped right through both coats of paint. Hmm. I figured this was an anomaly. But after finishing the stripes, the size of the problem became clear.


    Once the paint was fully dry we peeled back the tape. In two or three spots the paint just peeled back with the tape. We were shocked. Dozens of strips of paint, up to 3 inches long, came peeling back with the tape. And not just the top (dark blue) coat, but the base (medium blue) coat came up also. It peeled right back to the original paint.


    The experienced (or professional) painters out there are no doubt shaking their heads at me.


    I was certain that what I was doing was fine. Even now, several weeks later, after having done lots of reading, I still find that the general advice out there is conflicting. For example, I have read in a few places that acrylic latex paint, which was what I used, can be safely applied over oil. (Not!)


    After checking around for advice, I came to accept that the latex paint had to come off the wall. There was no product out there that we could paint over it and have “soak through and hold”. Believe me, this took some time, a bit of “mourning” if you will. After all that work on cleaning, painting, as well as the work with setting up the stripes... the thought of having to strip it off was almost heartbreaking.


    (On the plus side, I did actually find that I didn’t like the striped effect. The paint colour was too dark. That was our slightly silver lining to that huge cloud.)


    I first tried washing the wall with Methyl Hydrate. Yes, it took off the paint, but the process very slow. The rag would almost immediately become saturated with paint. I could foresee myself needing a few garbage bags full of rags if I was to continue.


    Next I tried power sanding. Nope. Dust everywhere, and sloowwwww.


    What worked, in the end, was water and elbow grease. We washed the wall with water. Once wet, the latex seemed to loosen up a bit, and paint scrapers would take it off.


    The dark stripes – the ones with four layers of latex – actually came off much easier than the ones with two layers. The kids had fun with those stripes. With a bit of care they could peal back a layer of paint almost the size of a sheet of paper. See the photos below for some shots of the gang at work, and of some of the paint being peeled.


    I didn’t try to keep track, but it took a fair bit of time to scrape all four walls of this twelve-by-twelve bedroom. I collected the paint fragments in a grocery bag, and ended up with a lump of paint peelings certainly larger than a full gallon can of paint.


    Once 98% of the paint was off the walls, we washed again, and then painted on two coats of original Kilz primer. This was on the advice of an experienced painter that I chatted with over email. The Kilz primer is an oil based product. I was warned that it had a very strong odour, and so I painted with a respirator. But interestingly, and to our great relief, the odour disappeared within just a few hours.


    Two coats of light blue latex (satin) went on next, and we’re at last finished. There is also an “after” photo, below.


    I never, ever, want to do that again. And so I “embarrass” myself a bit here in public, in hopes that others can learn from our misfortune.
    Attached Images Attached Images
    Last edited by Art Mulder; 04-23-2006 at 8:27 PM.

  2. #2
    The blue paint failed to bond to the wall. What a drag. I have learned over the years always to clean and prime before painting. I have had this same experience with paint peeling off the contaminated wall before.
    Chris

  3. #3
    Join Date
    Mar 2004
    Location
    Toronto, Ontario, Canada
    Posts
    3,789
    Been there, done that!

    And Art, as a result, I can really appreciate how frustrating it was for you.

  4. #4
    Join Date
    Mar 2003
    Location
    SE PA - Central Bucks County
    Posts
    65,694
    Did you use primer before your latex color coats???
    --

    The most expensive tool is the one you buy "cheaply" and often...

  5. #5
    Join Date
    Apr 2006
    Location
    Ewa Beach, Hawaii
    Posts
    76
    When in doubt...primer primer primer! That Kilz is some good stuff.

  6. #6
    Join Date
    Feb 2003
    Location
    Lafayette, IN
    Posts
    4,563
    While it's too late now, an ammonia-based cleaner (Windex, Dirtex, etc.) would have done wonders for helping to get the new latex paint off.

    You can put acrylic/acrylic-latex/latex over oil, but only with proper prep. You have to either de-gloss the oil (with, what else, a de-glosser, basically a chemical cocktail, or by sanding), or you have to use, as you did, a bonding primer such as BIN or Kilz, or one available at various paint stores.

    I'm glad you were able to persevere and overcome!
    Jason

    "Don't get stuck on stupid." --Lt. Gen. Russel Honore


  7. #7
    Join Date
    Feb 2006
    Location
    Southern Ontario Canada
    Posts
    430
    I ran into the same problem here. We bought this place 3 years ago and later found out all the window trim, door moulding and baseboards had been painted with oil paint originally then repainted with latex. So... as time and cash permit I am ripping all the old trim off and replacing it with new oak trim I am making in the shop. One room at a time.. It will get done someday honest.
    Rick
    I support the Pens for Canadian Peacekeepers project

  8. #8
    Join Date
    Dec 2005
    Location
    London, Ont., Canada
    Posts
    2,200
    Quote Originally Posted by Jim Becker
    Did you use primer before your latex color coats???
    No I did not, Jim. I thought that my mistake was clear from my post.

    I've painted latex-over-latex (w/out primer) for ages. The only time I've bothered with primer (on already painted surfaces) was when the original paint was particularly dark. When the base paint is reasonably light, I've found that two coats of new paint cover just fine, so why bother with the time and expense of priming?

    Prior to this February, considering that my previous house was a 50yr old dwelling, I would have also guessed that I had at some point painted latex-over-oil on those old walls. But evidently not.

    Quote Originally Posted by Jason Roehl
    While it's too late now, an ammonia-based cleaner (Windex, Dirtex, etc.) would have done wonders for helping to get the new latex paint off.
    Interesting idea, Jason, I didn't think of that. Is that because ammonia is part of the solvent in latex paint? There sure is a mild ammonia scent when painting with Latex.

    Quote Originally Posted by Lopaka Garcia
    When in doubt...primer primer primer! That Kilz is some good stuff.
    Or at the very least, test test test. If you aren't sure of what is on the walls, you can also just paint a 1ft square section with latex, and then check later and see if it sticks, or peels off.

    ...art
    Last edited by Art Mulder; 04-24-2006 at 7:37 AM.

  9. #9
    Oil base paint won't even stick to itself without some 220 sanding and I've found 150 is even better.
    Dennis

  10. #10
    Join Date
    Mar 2005
    Location
    Atascadero, CA
    Posts
    235
    I liked how you had the kids scraping off the paint. They had to make rent .

  11. #11
    Join Date
    Mar 2003
    Location
    SE PA - Central Bucks County
    Posts
    65,694
    Art, sorry...I missed something in the first post and hence my primer question. At any rate, I feel for you...the trim work in the 250 year old portion of our home is oil-based and it's going to be a pain when I go to change the color from the blue it is now (which I dislike) to something else later...
    --

    The most expensive tool is the one you buy "cheaply" and often...

  12. #12
    that's why I prefer to paint latex outside, too much to sand. Latex sticks to itself no matter what!

    Quote Originally Posted by Dennis McDonaugh
    Oil base paint won't even stick to itself without some 220 sanding and I've found 150 is even better.

  13. #13
    Quote Originally Posted by Mike Hollingsworth
    that's why I prefer to paint latex outside, too much to sand. Latex sticks to itself no matter what!
    Yeah Mike, latex is the way to go outside. Here in south Texas the sun just eats up oil based paints. It just turns to chalk and disappears. I do like it for trim inside because it has higher gloss than latex.
    Dennis

  14. #14
    Join Date
    May 2004
    Location
    N Illinois
    Posts
    4,602
    I feel your pain...Sorry abiout your mishap..Sanding and primer prob would have helped...
    Jerry

  15. #15
    Join Date
    Feb 2003
    Location
    Lafayette, IN
    Posts
    4,563
    Quote Originally Posted by Art Mulder
    Interesting idea, Jason, I didn't think of that. Is that because ammonia is part of the solvent in latex paint? There sure is a mild ammonia scent when painting with Latex.
    It's not a solvent in any latex paints that I'm aware of. In fact, you'll often find that latex paints contain an acid of some sort (propenoic acid comes to mind). However, many strippers are strong bases--does their slippery feel come to mind? The ammonia is mild enough that it really doesn't do well on cured paint (latex takes two weeks to a month to fully cure).

    My partner swears up and down that a given might have ammonia in it, but I have to show him the label every time. Probably the worst is "Gripper" from ICI/Glidden/Dulux. That does have a strong ammonia smell, but no ammonia is on the list.
    Jason

    "Don't get stuck on stupid." --Lt. Gen. Russel Honore


Similar Threads

  1. Lesson Learned?
    By Mark Plough in forum Off Topic Forum
    Replies: 5
    Last Post: 09-23-2005, 2:28 PM
  2. Lesson learned
    By Kevin Arceneaux in forum General Woodworking and Power Tools
    Replies: 2
    Last Post: 05-30-2005, 10:12 AM
  3. Lesson Learned
    By Tom McMahon in forum Neanderthal Haven
    Replies: 9
    Last Post: 02-16-2005, 1:47 PM
  4. Lesson learned on my MM16 BS
    By Alan Tolchinsky in forum General Woodworking and Power Tools
    Replies: 14
    Last Post: 10-21-2004, 11:07 PM
  5. Lesson learned the "Hard Way".........PICS
    By Gord Graff in forum General Woodworking and Power Tools
    Replies: 2
    Last Post: 08-23-2003, 2:11 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •