After reading of Randy's travails with his Cobra reduex, I thought it might be helpful to post a most recent experience with doping during high humid conditions.

I travelled down to Floeida to visit Walter Umland, and to attend the KOI. Of course, it had nothing to do with all the sub freezing temps, and snow and ice in Utah this time of the year.

When I got there, Walter was working on the finish for his Prototype Ringmaster Imperial.

The first day, the temps were in, or near 8o degrees. Humidity, on his meter was about 50%. He sprayed on a coat of silver, and commented on the blush he was getting.

We tried a lot of things to get around the problem, especially in light of the fact that during the process the temps dropped and the humidity rose to over 90%.

What worked for us, and allowed us to mask the trim, and apply the two main trim colors, all on the same day was suprizing in it's simplicity.

Of course a small amount, 10% or less, of retarder was used, but the key was that Walter has a home heating and air conditioning unit in his shop. We set the meter in the shop, and ran the air conditioning until the meter showed less than 35% humidity. We turned off the AC, and shot the color. As soon as the color was shot, we turned the heat up to 80 degrees, and went inside for an hour or so. The humidity stayed low during most this time, since the doors were left closed while we were force drying the paint.

An hour or 2 later, we were able to handle the plane, and mask off for the second trim color. We then did the same procedure again, a couple of hours later, were able to remove all the masking. We left the plane in the heated shop over night.

The best part was we experienced no blushing, and were able to add the black checkerboards, and 3 coats of clear the next day.

The plane came out with a pretty nice looking finish that should buff out real nice in a few weeks.

This information is offered as a help and your milage may vary.

Mark,
Of course in your case (low outside temperatures) just running the heater should keep the humidity at bay.

I'm no expert but when you heat air the moisture in it goes down as warmer air can hold more moisture. Thats why you blow warm air on windshelds to de frost them. And cold drinks sweat  cause the air around them give off moisture as they cool. The moisture is coming from some were and I would check your heater exaust but if your using a space heater thats where its coming from. As any gas burns it gives off moisture some more than others. Had an LP heater in a fishhouse once and the doors froze shut because of the air leaking out them built up ice.

Edited; a barometer does not mesure humidity I know you knew that.

Randy.,I keep tellin ya, you need to find a conferance or somthign you have to attend over here, bring the beast over, and we can have a painting party in the downdraft!

Mark,

Yea, yea.

Alan,

I suspect it has to do with the heating and cooling of the shop. The place it's normally heated (I really need to get central heat in there). I'm sure the condensation when it cools and the heat when I heat it up to be in there causes most of the problem.

My original comment was directed to (I think!) the fact that it was (very) cold outside, whereas inside we are talking temperatures in the lower 70's (yes I know you need air conditioning in Florida even in the winter to achieve this indoor temperature!--it was in the 80's during my Christmas visit last month in Miami).
For example right now (outside) it is 9^oF with the %RH (also outside) at a "sticky" 73%. Inside where I am sitting, according to my instruments, it is 21^oC (70^oF) and a %RH of 13%.

Now if you are heating the room by some catalytic fuel heater, this could be dumping moisture into the room (hopefully no CO!), so what I say doesn't work. An electrical heater would be better.

I'v had problems with the exaust from a kersone heaters mixed with painting. Fish eyes and adhesion problems with auto paints at least here in MN.