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-   -   Paint failure at floor registers (http://www.diychatroom.com/f4/paint-failure-floor-registers-315/)

JOISTMAN 01-30-2005 01:02 PM

Paint failure at floor registers
 
50 year old home-plaster walls. Bare plaster at some floor registers. Cleaned sooty residue from bare plaster (and from painted plaster) with White Lightning. Washed with 30% ammonia + water. Rinsed twice. Repaired dents and holes with drywall mud. 1 coat oil based Kilz. 2 coats SW 25 year interior satin latex. Caulked @ base board and wall with Dap acrylic paintable caulk. Used SW Pro Mar 200 Oil base High Gloss on baseboards. Looks great. 6 months later I notice a crack in paint above floor register. Using a razor scraper I very easily chipped off the paint. It had separated from the bare plaster. About 3 or 4 square ft. There was a powdery residue on the plaster that smelled like slightly burnt rubber or latex. The caulk (and oil based paint) at the baseboard was cracked and starting to separate from the wall. I repaired the area as stated above. I also inspected the duct work to make sure there was a reasonably good seal to the floor register. I also installed an air deflector to guide the air over the floor instead of straight up over the wall. 6 months later...it happened again. It also occured at a different register.In this instance I had Kilzed and painted over the existing paint coat(It was not bare plaster). I think I have 2 separate problems. Wall paint failure and caulk / paint failure where the base board meets the wall. This second problem has occurred at areas other than registers. Did most of the painting in warm weather and most of the problems started in cold weather. Any words of advice from you professionals?

ProWallGuy 02-04-2005 07:46 AM

My first thought would be that Kilz is not the appropriate primer for this situation. Kilz is formaulted to be a stain blocker, not a bonding primer. I would try using a heavy-bodied, slow drying 'long' oil, such as Ben Moore enamel underbody and see how that holds up.

JOISTMAN 02-07-2005 07:25 PM

Thanks for the tip.

Humble Abode 03-22-2005 12:00 AM

Did you say you used an oil based primer and then a water based topcoat?

From what I understand, and I could be wrong, latex paint (topcoat) doesn't bond well with an oil based primer or vise versa. If you use an oil primer also use an oil topcoat. They are desinged to bond to eachother.

housedocs 04-30-2005 12:19 AM

I'm not a professional painter, but I can handle a brush or a spray rig. I always thought the same thing about the oil and latex, but unless I'm mistaken prowall is talking about an oil based enamel, please correct me if I'm wrong PW. The primary reason for the paint failure was as stated, the improper primer used IMO as well.:cool:

ProWallGuy 04-30-2005 10:23 AM

As for the original poster's failure, I really don't know what caused it. sounds like he prepped/primed etc. very thoroughly. I merely mentioned his choice of primer was my first choice at all.

IMO Kilz is overrated and over marketed for all the wrong applications. Its name alone explains what it is supposed to do. It kills stains. It is not formulated to be a bonder, underbody, or any other benefit of other primers.

The BM enamel underbody I suggested is what they call a 'long oil'. It is very thick, and dries real slow. It penetrates and levels minor imperfections, and provides a good basis for oil or latex topcoats.

Now, for latex/oil systems, this is what I was taught. All houses/substrates flex/move with temp/humidity changes. Some more than others. The main concern with mixing the two types in one system is that oil dries hard/rigid/brittle, and latex dries soft/pliable/flexible. For interiors, this rarely poses a problem. For exteriors, it can become an issue. If some siding expands due to humidity, and it was primed with oil, finished with latex, the primer underneath being hard/rigid, can crack and peel off because it can't keep up with the expansion. This is where you might see total paint failure (primer & topcoat). If its primerd with latex, and finished with oil, the primer flexs with the expansion just fine, yet hard oil topcoat is brittle and shears off the primer.
These are just 2 examples. I'm no way a paint or cheist expert, this is just what I was taught or learned over the years. I personally have never had a failure due to mixing oil/latex in systems (never latex over an oil finish coat, only primers) but I also don't do exteriors either.

Teetorbilt 04-30-2005 11:48 AM

Note Pro's last statement. This has been my experience as well.
I don't use latex primers anymore. Epoxy, oil and shellac rule.

Humble Abode 05-01-2005 01:32 PM

Quote:

Originally Posted by Teetorbilt
Note Pro's last statement. This has been my experience as well.
I don't use latex primers anymore. Epoxy, oil and shellac rule.

And you use latex topcoats over these products with no problem? Do you think it is a more effective and longer lasting proccess or is it just personal preferance?

We, as a company, use primarilly Bullseye 1-2-3, and I drive past and look at all of our past jobs every year at the begining of the summer to see how the paint held up over the winter.


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