How to Block Tough Wall and Ceiling Stains

        Ever had a massive stain on your walls or ceiling?
  Usually in my work as a interior painter in Northern Kentucky I find a lot of water stains on ceilings. The cause is most often always a leak from a upstairs bathroom.

  The #1 questions that I get asked from those seeking painting advice, is how to block these stains out.

   In recent years many paint manufacturers have released Latex- water based stain blockers and primers. And many of them have ( Big Promises) on the labels to tackle tough stains with ease. The truth i have found out about these water based primers/ stain blockers is that while many of them are excellent primers that promote great adhesion for top coats, their stain blocking capabilities are very limited. Especially Especially against Large Water based stains.

   So my advice for those who seek it on stain blocking is and until someone shows me proof of something better, to reach for good ol’ Oil Based Kilz.

  When I need to block stains and make sure they don't bleed through correctly and I don't have time to play games. I go with Kilz.
And that's no matter the cause of the stain, whether it be oil based or water based, or blood, or some identifiable base,

 I always reach for kilz. Oil Based Primer. ( The Original)  

  Now im using kilz sort of generically, there are several different brands of oil based primers… You have 'Pro Block’ from Sherwin Williams
And then Zinnser has a product called ‘ Bullseye 123. ….

Any of those will work. The great thing for consumers is most come in a spray can, and for ceiling stains most even have the kind of can that sprays upwards so you don't have to tilt the can and deal with the hardship of it not wanting to spray properly.

Now In rare rare cases i have seen a stain bleed through a oil based primer/stain blocker and i mean even several coats.

 I recall a ceiling in Union, Kentucky on a commercial painting job that my company ExtraPrep Pro Painting contracted. We had a ceiling that we put multiple coats of oil based stain blocker on and the stain continued to bleed through. In these rare cases i have found a solution as well.

  What i will do is take a clear coat of urethane it is also available in a can or by gallon. I'll take that and apply it to the stain, make sure i give it plenty of time to dry. and then i'll take some 220 grit sandpaper and just lightly sand it for just a few seconds over the entire surface…. just enough to ruff the clear coat up a little bit but not sand it completely away is the key here. After that i'll just top coat with the paint we are using and i've never had anything bleed through that.

  One last thing i'll give you advice on… There is alternative stain blocker on the market and its called shellac. It is tough stuff. And it will block stains just as well as Oil based in my opinion. However the reason I don't use it often is because i feel that its finish is a little texturized especially in spray cans.  It doesn't finish mirror smooth for me often, so while it is a heavyweight stain blocker. It does at least in my experience leave something to be desired in its appearance value.

  There are tons of text book procedures when it comes to stain blocking and priming. I have taken and seen the course material from institutions and paint manufacturers about using oil based to block water, amd water based to block oil, and how you shouldn't lay this over that and so forth and so on.

 Don't waste your time. Don't waste your money.
Reach For a Heavyweight Stain Blocker when dealing with large rich stains. Grab a Can of Kilz or a Can of Shellac and give it proper time to dry before you topcoat.

  I hope this helps someone looking for advice on Stain Blocking while painting.

Anthony Ford


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