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-   -   Question about painting with Kilz (http://www.houserepairtalk.com/f107/question-about-painting-kilz-8814/)

maxpatch 03-08-2010 01:46 PM

Question about painting with Kilz
 
I have a stain on my ceiling that I need to cover with Kilz.

1. Can I spray Kilz over just the spot and then repaint the entire ceiling? (Will ceiling paint cover where I used the Kilz?)

2. If I paint the entire ceiling with Kilz will I then "have" to repaint the ceiling with ceiling paint? (Or will just the Kilz look good?)http://www.houserepairtalk.com/editpost.php?do=editpost&p=41972

kok328 03-08-2010 01:58 PM

Quote:

Originally Posted by maxpatch (Post 41972)
I have a stain on my ceiling that I need to cover with Kilz.

1. Can I spray Kilz over just the spot and then repaint the entire ceiling? (Will ceiling paint cover where I used the Kilz?) Yes

2. If I paint the entire ceiling with Kilz will I then "have" to repaint the ceiling with ceiling paint? (Or will just the Kilz look good?)http://www.houserepairtalk.com/editpost.php?do=editpost&p=41972

Yes - entire repaint. Kilz doesn't need to be applied like paint in terms of see thru coverage.

Bud Cline 03-08-2010 05:12 PM

Use the "ORIGINAL" Kilz. Don't waste your time with the new and improved Kilz - because it's not.:)

Nestor_Kelebay 03-08-2010 06:13 PM

Max:

When a stain bleeds through paint or primer, what's actually happening is that the stain is dissolving in either the water or mineral spirits of the water based or oil based primer or paint.

KILZ is actually an ordinary oil based primer. The difference is that instead of using 100% mineral spirits as the thinner like other oil based primers, it uses a 60% naptha and 40% mineral spirits mixture as the thinner. Naptha evaporates many times faster than mineral spirits, and so KILZ dries much faster than an ordinary alkyd primer. The whole idea here is to have the KILZ become too thick too quickly for the stain to migrate to the surface and discolour that surface. That would result in the stain "bleeding through" the KILZ.

If the stain was caused by water, or anything water based, it probably won't dissolve in mineral spirits, and you could probably use ANY oil based primer to hide it.

Also, I see absolutely no reason for repainting the whole ceiling with KILZ. If the KILZ area shows through your paint, you just need to apply another coat of paint.

About ceiling paint. Ceiling paint is nothing more than a low quality wall paint. They don't use as hard binders in ceiling paints because you generally don't have to scrub stubborn marks off of ceilings like you do walls. If it were me, I would use a higher quality wall paint on your ceiling to get better hide of the white spot caused by the KILZ (or other primer).

If you do opt for using any other oil based primer, try to get a high hiding primer. Often primers don't have good hide, and that requires several costs of primer or paint to cover a patch.

Bud Cline 03-10-2010 03:24 PM

Shellac!

KILZ is pigmented shellac. Shellac seals most everything and won't allow stains to penetrate.:)
If you use shellac you will have to repaint however cause the shellac will be yellowish.:)

Nestor_Kelebay 03-10-2010 07:46 PM

Bud:

BIN Sealer (made by Zinnser) is a shellac based primer.

KILZ Original (made by MasterChem) is an "oil based" (alkyd) primer.

Both are meant to be used as stain blockers, but it's simply not very difficult to prevent a stain from bleeding through a primer if you use a primer the stain doesn't dissolve in. If it's a stain on a ceiling, it's usually caused by leaking water, and water based stains won't dissolve in an oil based primer.

So, most stains that KILZ will block could have and would have been blocked by any oil based primer. KILZ claim to be a stain blocking primer rests entirely in the fact that it uses a 60/40 solution of naptha and mineral spirits as it's thinner, so it dries much more rapidly than typical alkyd primers that use only mineral spirits as the thinner. The idea here is to have the primer dry so fast that anything that dissolves in it doesn't have time to diffuse through the primer film to the surface and discolour it before the primer film is too thick to allow diffusion through it.

If the stain bleeds through both an oil based and latex primer, it's not a "stain" at all, but simply dried up dirt that's getting both primers dirty.

The trick in blocking stains is simply to use a primer that the stain won't dissolve in. You can check to see which kind of primer will work first by simply cleaning the stain with a paper towel dampened with water and one dampened with mineral spirits. A stain that dissolves in alcohol will bleed through a shellac based primer like BIN.

Bud Cline 03-11-2010 03:14 PM

Yow, got that part, you said that already.:)


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