Spray painting on humid days

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joepolicy

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It has been cool and wet here in Germany and for the first time, I started having troubles with spray painting. My glossy paints would dry dull and the clear coats were milky with little rainbow effects. You know, the usual problems associated with paint and moisture.

Since I could not find a de-humidifier anywhere, I thought I would try using a $10.00 1875 watt hair dryer....and it worked!

What I did was:

1. Use the hair dryer on it's highest setting to warm up the parts to be painted. I kept the areas I warmed up small so they would not cool down much.

2. I then applied the paint as usual

3. I then used the hair dryer on its low heat setting to quickly cure the paint. It worked 100% of the time, my glossy paints stayed glossy and the clear coats stayed clear.

I did run into a some lessons learned. The first being if you are painting a large rocket like an HPR, only work on 1/3 of the area at a time. If the parts get too cool before painting, you will still get the cloudy, dull halo'd appearance. And, when using the low heat setting, keep the hair dryer moving at all times. The fresh paint tends to bubble up if left in one place for too long. I ended up using the diffuser that came with the dryer to help spread out the air so it was not so forceful in one area.

I tried this over both primered surfaces and ones that had been painted with a white paint undercoat. I used it on both Krylon and a local German brand of spray paint with the same results.

Takes a little practice, but the results are well worth it if you have to paint on a humid day. Another advantage of the first step is that the hair dryer tends to blow off any small particles of dust that seem to quickly accumulate no matter how many times you use the tack cloth. Especially with Quantum Tubing which generates static electricity when rubbed - it attracts everything!

I am also going to try this using an infrared lamp in place of the hair dryer set to low in step 3. I think it will work even better. I will post results as soon as I get the chance to test it out.
 

Steward

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Now that you have discovered one of the many old rocketry secrets.... Now we have to kill you......!!!!


LOL
 

joepolicy

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Originally posted by Steward


Now that you have discovered one of the many old rocketry secrets.... Now we have to kill you......!!!!


LOL
It was new too me....I wish someone had told me about it before I ruined two rockets...I love resanding and refinishing, really I do...Of course, I don't have to anymore!
 

eugenefl

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Originally posted by joepolicy
It was new too me....I wish someone had told me about it before I ruined two rockets...I love resanding and refinishing, really I do...Of course, I don't have to anymore!
I've never heard of this done before. Friggin' Florida rainy/humid weather ruins near every paint job I ever try! Nice tip. I have an electrical outlet outside that I could hook up a hair dryer to.
 
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