Wet Paint!

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Posted by Danny Baronian on January 16, 2002

I primed several panels for a rush job, then applied a coat of bulletin enamel, straight from the can. After 26 hours, the paint is still slightly tacky.

The first coat was applied in the afternoon with the weather the mid 50’s during the day, cooler at night, with fairly low humidity.

Could the panels be forced dried to apply the second coat, and if so by what method. When applying the second coat would the addition of Japan Dryer be advisable, and if so how much?

Thanks

Danny

Jeff Lang

Danny,

I saved some notes about this problem from Kent Smith.
"When the dryer is in question, a simple solution is to take a spray bottle with hydrogen peroxide in it and mist the air lightly above the surface. Allow the mist to fall and this should dry the paint or varnish in an hour or so. Air flow at this time certainly is important. Keep this trick for future reference. This only works on alkyd enamels and related varnishes, not urethanes or acrylics although it will work on waterborne acrylics. Caution, don't mist too heavy or the finish will water spot."

good luck,
Jeff

Rick Sacks

I don't remember the chemistry of this, but the peroxide misted creates an atmosphere above the surface that draws something from the unruly paint, causing it to cure.

Cam

If I have my chemistry right, alkyd paint dries as the resin molecules bind with oxygen. Hydrogen Peroxide is a water molecule with an extra oxygen atom (h2o2). The extra oxygen molecule has a very weak bond and easily escapes as a gas. This would put a lot of oxygen in intimate contact with the resin, speeding the drying process.

I'm not a chemist. But I did stay at a Holiday Inn Express last night.

Carol

What primer? What substrate? Ah, those rush jobs!

Danny Baronian

Sherwin Williams , exterior wood latex primer and Medex.

Vance Galliher

hey danny......i hope your medex is for interior application........if not, don't waste your time !use a different substrate.........vance

Carol

Vance, you took the words right out of my mouth.

Jeff Lang

Danny,
I suspect the water based primer had not fully dried & the remaining moisture is causing your oil based paint to cure much slower. I have heard that if oil is going over latex, let the latex dry at least overnight (12 hrs I suspect). Have you ever tried XIM-UMA available at Sherwin Williams?
This waterbased primer I like to use as it dries fast & sands nice. Too little, too late? Maybe next time.
Good Luck,
Jeff

Danny Baronian

Haven't heard of XIM-UMA, but will try it next time. I've found their products to be very reliable, and the primer that I have been using ( S/W) dries in aprox 45 minutes, and easy to sand without cloging.

I would not suspect the primer as it had about 6 hours to dry. I sanded before applying the enamel as usual, and it appeared ready for the enamel coat.

I think the main problem was the temperature, it was just too cold. I believe your in PA, correct? What is a normal time for enamel to dry this time of year in your area?
Thanks,

Danny

Jeff Lang

Danny,
I am in Pennsylvania. It gets moderately cold here but not too bad.
In the winter months, the forced air furnace removes much of the humidity from the air, leaving my paints to dry more consistantly. I am a believer that air movement helps paint dry better than heat, excluding extremes. Heat seems to make my paint dry on the surface first, then the paint remains soft, especially with oil base. But, air flow circulates new air to allow the solvents to evaporate at the proper rate.
Enamels, for me seem to dry at different rates.
On an average, I would say One Shot colors dry between 6-10 hours. Burgundy & one of the blues if i recall were the slowest with black & white being the fastest.
I use more latex finishes lately, & try not to rush whats out of my control.

I have heard, if you sand first, you may need to wait a while before coating, as you may remove a dried layer & expose an uncured surface.

good luck,
jeff