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Paint Blush... What is the cause?????


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#1 Dragline

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Posted 18 November 2009 - 10:41 AM

I used Duplicolor flat white primer, then one of those small cans of Duplicolor touch up.


I got blush soon after on one body. I quickly re-sprayed and it's gone. I keep spraying the other and it's still blushing.


Coats are [primer to color] about 20 min. Colors coats are wet in wet [as much as you can with this stuff, it dries soooo fast].


I'm thinking that i'll let the one that is still blushing to dry thoroughly before a final coat to avoid this, but the other one came back just fine.


Thoughts?


Bob F

PS: If it's still blushed and I let it cure, if I clear it will it come back?

Edited by Dragline, 18 November 2009 - 10:45 AM.


#2 Marc @ MPC Motorsports

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Posted 18 November 2009 - 10:57 AM

Humidity is a primary cause. Where do you paint?

#3 Chillyb1

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Posted 18 November 2009 - 10:58 AM

I know the cause if not the cure. Humidity is the problem and it is usually only a problem with lacquers. Some are more sensitive than others, even within lines of paint, e.g., some Plasti-kotes never blush and others do like a ... (fill in your favorite simile here).

I recently had this problem with a Plasti-kote color. Some of it went away with clear, but not all. I had to strip it and am trying a Duplicolor instead (the same stuff you are talking about in a small can). My first try, spraying out of the can, led to super blushing. I am currently trying the same paint through the airbrush (in fact, as soon as I finish typing this I have to go check it to see how it came out).

In the past I've been able to save such blushed paint jobs by waiting for a low-humidity day and painting over the whole thing.

Good luck.

#4 Guest_Gramps-xrds_*

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Posted 18 November 2009 - 10:59 AM

Bob the blush is caused by the moisture in the air and the speed of the paint flashing off thinner. As the paint flashes the moisture in the air condenses on the paint. That's just part of using lacquers. The solution is, use slower thinner or find some way to reduce the humidity where you're painting.

#5 Dragline

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Posted 18 November 2009 - 11:15 AM

Humidity is a primary cause. Where do you paint?

My Mums lives about 10 adresses up the street. It's her row house so there's a basement. I painted the one that is still blushing, outside in the sun.


It's not humid here, at least not that I can tell. This Duplicolor flashes very quickly. I'll let it dry overnight and spray it indoors in the basement. The furnace it in the room I spray in [when indoor spraying] and it's always dry there.


This is a first for me. it's also the first time I've tried these can of touch up. The price is better than tamiya and there are many lovely colors available.


I sprayed a REALLY wet coat and came home about 1-1/2 ago. It seemed like it was doing it less every time I put paint on it. It's a Funny Car so panel lines are not an issue, but I don't want it to start waving either. This paint really sits down nice and you cannot make it run. I even tried to make it run and it literally just built up on my test scrap.


I'm going to go look at it shortly. I may take a few pics and post em.

Thanks guys

Bob

#6 sak

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Posted 19 November 2009 - 02:17 PM

Sometimes it is humid even though it doesn't feel like it. Basements can be humid areas. Word of advice, not really safe to be using that stuff indoors period, let alone in a furnace room.
Jeff

#7 Ddms

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Posted 19 November 2009 - 05:58 PM

If you live in Baltimore, you are almost certainly painting in humid conditions. The humidity in Baltimore as I write this is 100%. That is definitely high. For comparison, the humidity in Burbank, CA, is 49%.

Edited by Ddms, 22 November 2009 - 09:29 AM.


#8 Guest_Gramps-xrds_*

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Posted 20 November 2009 - 04:41 PM

My Mums lives about 10 adresses up the street. It's her row house so there's a basement. I painted the one that is still blushing, outside in the sun.
It's not humid here, at least not that I can tell. This Duplicolor flashes very quickly. I'll let it dry overnight and spray it indoors in the basement. The furnace it in the room I spray in [when indoor spraying] and it's always dry there.


Trust me, it IS humidity causing it. That's just something that some lacquers do. Since you're using spray cans you can't change thinners. So either reduce the humidity or heat the place up to at least 80 deg or higher and there's no real guarantee it still won't do it.

#9 charlzrocks

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Posted 21 November 2009 - 07:46 AM

Is blushing when a gloss lacquer dries with a satin finish?
what exactly is blushing? :rolleyes:

#10 Guest_Gramps-xrds_*

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Posted 21 November 2009 - 08:27 AM

Is blushing when a gloss lacquer dries with a satin finish?
what exactly is blushing? :rolleyes:



Yes, lacquer will dry to a dull finish when it blushes and it'll get a grayish haze that is impossible to get it all off. You can color sand it and clear coat. That'll just about get rid of all the haze. Clear coat alone won't do it though.

#11 charlzrocks

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Posted 21 November 2009 - 09:38 PM

Thanks....I ran into that with some Krylon and figured that was the problem! Mississippi gets pretty humid!

#12 ramonesblues

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Posted 31 December 2009 - 01:01 PM

Spray some straight lacquer thinner on it. That will release the trapped moisture. I painted in the SF bay area, and was a common fix as it was always humid there.

#13 E St. Kruiser50

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Posted 02 January 2010 - 07:38 AM

Humidity isn't the only issue, so is temperature - that's why "real cars" are sprayed in a controlled enviornment spray booth.

I have a small 5' X 10' walk-in spray booth, that is heated by a oil-filled recirculting space heater (No element or flame to blow you up Posted Image ).

As I live in very wet and cold Oregon, I want to spray in a controlled enviornment, and for me, along with the lighting, and the air-forced ventilation, this was a pretty inexpensive way to solve the problem for the last 8 years.

In the dead of winter, even with snow on the ground, I can usually get to 80 degree's in there with no problem, and paint loves that temp. and low humidity, lays down beautifully, drys super quickly, and cures much faster Posted Image .

#14 circaboy

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Posted 01 October 2013 - 02:10 PM

When I ran Through this promblem with my dupli color clear, I Tryed to lay down a couple coats of Tamiya clear on my model to see what would be happening and guess what? The shine came back! :)  So I guess these Dupli-color cans are VERY sensitive to humidity since I never had a problem with Tamiya,even on 70-80% humidity level days



#15 vypurr59

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Posted 01 October 2013 - 02:50 PM

Don't try to give it a wet coat. As it is drying, it is gasing out the thinner. Light mist coats, when the humidity is high, is a much better way for the paint to gas out and not blush.  Just my thoughts and I paint in high  humid conditions alot.