Spraying in the rain, just spraying in the rain...

[Mark Hammer]

....what a glorious feeling, I'm building again.

Bad Gene Kelly imitations aside, I've finally acquired some chassis and am finally going to make good on some promises to about 5 or 6 people.  Winter has gone, and once again I can work in the garage with the door open to let the fumes out.

Here's the thing, though.  It's damp out there, and just cool enough that I wonder if I should be concerned about condensation interfering with painting  and clearcoating these boxes.  I have a toaster oven for baking the finish, but I wonder about what moisture might get trapped under whatever I spray on the boxes.

Does ambient dampness compromise spray-painting?  If so, is there a way around it, or do I need to wait for a dry sunny day?

[SpencerPedals]

It rained half of last summer here, and while I etch and didn't have to worry much about it on the pedal projects, it was a pain to clearcoat other things.  You run the risk of experiencing blushing:

http://www.sherwin-automotive.com/reference/troubleshooting_guide/blushing/index.cfm

Painting in humidity is not a lot of fun at all.  But if you decide to etch, you're sanding most of it off anyway...

[petemoore]

  To some extent it depends on the product. Some labels even say don't spray in humidity above X amount..and temperature recommendations.
  Hazy is what it looks like if the curing process takes place in too much humidity, I'd imagine inside a warm oven the humidity drops markedly, or is it just the same % but warmer...
  I always consulted our barometer/humidity indicator before shaking the can.

[Mark Hammer]

Thanks for the replies, folks.

I'm wondering if warming up the boxes before spraying might help.  Not heating them up, necessarily, but at least raising their temperature to a point where there is no condensation on the outside of the boxes before I spray.  I.E., hair dryer warming, rather than heat gun warming.

Or is is moisture that comes with the paint, rather than moisture on the surface of the box and trapped under the paint, that I need to be worried about?

[moosapotamus]

Warming before spraying was what I was thinking, too. I think it would be worth a try.

Also, I've gotten blushing in clear coat before, but I was able to get rid of it with heating.

~ Charlie

[Top Top]

Wouldn't heating the box attract more condensation in cool/damp weather?

I would think having them at the exact ambient temperature, and the paint as well, would be the best way to avoid attracting moisture.

[Mark Hammer]

It'll be between 7 and 11 Celsius here over the weekend.  I was figuring to warm the boxes up to maybe 18-20 Celsius.  Basically, room temperature.

[deadastronaut]

 no problems just keep out of any drafts or youll get blooming...(white streaky  dullness..)..

takes longer to dry if damp though..........room temp is best...

is sometimes spray and then move it onto a radiator whilst hot...this semi bakes it on..nice finish too...

makes it a bit quicker too handle...

i presume your using cans..acryllic..?.. cellulose..?...synthetic?...isocyanate..?...

ps. i used to spray cars

rob.

[phector2004]

Wouldn't heating the box attract more condensation in cool/damp weather?

I would think having them at the exact ambient temperature, and the paint as well, would be the best way to avoid attracting moisture.

nope. same reason why defrost works in a car.
Had a chemistry prof who dedicates a whole week teaching us about a big misunderstanding people have, that breaking bonds releases energy. In reality, breaking bonds needs energy, making bonds releases it.
its why steam burns you when it condenses on your hand

im sure warming the pedals up would help greatly, maybe putting some silica gel packs in the toaster? i usually throw a pack or two in my acoustic during summer, dont know if that's a good thing or not

Good luck with the paint!

[Nasse]

http://en.wikipedia.org/wiki/Dew_point

I did a spray paint job at the back yard one warm summer afternoon and it was just catastrophe while I did not feel the dampness beforehand. Perhaps it was just high humidity percent and overall temp was going down with sun, just enough for dew point happen. In rhe spring time firewood tends to get dry here even left outdoors without shelter and so does a wooden boat