I have a realy quick question what humidity is bad to do painting in? is it ok if it is raining but humidity is low? and final question when sanding and re-primering re-painting fiberglass parts would I do the same procedure as metal?

Thanks,

 

Hi Motosys------------In response to painting with either high humidity or rain it is usually recommended to pick another day-----------You can paint during these times, but when moisture is in the air it can cause problems with paint jobs--------Moisture is a high cause of "Fish-eye"------there are products out to minimize and prevent fish-eye------the product that I use is called "Smoothie II" or "Smoothie"------Smoothie II is for the new Urethane paints and Smoothie is for the older enamels-----------------Rain and high humidity can also intensify the possibility of the paint to run...........

Second question dealt with fiberglass prep----------Sanding on fiberglass is much more tedious process since you will need to be careful not to sand through the gel coat---------you can remove all the paint down to the gel-caot----but try not to sand through the gel-coat--------the gel-coat is what gives the fiberglass its strength------------you will NOT need to use an etching primer----------but you will need to use a filler primer-----------If you have plactic parts that you need to paint that flex----you will need entire different primers that flex------------

Hope that helped.
LaterZ, 81 TURBO

 

Humididty in the air will slightly affect dry time, but shouldn't interfere with how the paint looks. The real problem with humid air is droplets of water forming in the air hose from the air compressor. If you are using a proper air dryer, there should be no problem, but if you are painting with an unfiltered air line, it's best to wait until you have a dry day. Fish eyes can be caused by moisture, but more often they are due to oil or wax on the part. Fish eye remover is a last resort, clean air and clean parts don't need it.

 

if humidity is traped under the coats of paint after a few years you will start seeing tiny bubbles in the paint. as the temprature changes the water droplets under the paint will expand and contract and cause these little stress bubbles.

 

another problem you can can encounter with painting on high humid days is die back (if you're using an enamel) Since the paint doesn't want to dry as quick as other days people will tend not to wait longer between coats...and after you're done with you're paint job and it finally startts to set up you'll notice it's somewhat hazy or cloudy and doesn't have the gloss that you want. What happens is that since each coat doean't have enough time to dry the solvents are trapped in the paint and then when they want to evaporate they have to go through all the other coats of paint you put on and that gives it a hazy look.