Painting in these temps

OK, I'm in Omaha. Chilly right now but not so bad that I can't get some things done on the boat. I've got everything emptied out, motors are in the garage. Anyways, I'm washing the boat out now, about to flip it and do a light sanding, tsp wash, and a vinegar wipe down. My question is with the temps. Sunday a high of 45° I'd just like to spray (rattle can) my Rust-Oleum primer. Then Monday afternoon first coat of Rust-Oleum smoke gray oil based rolled on, second coat on Tuesday. The temps are dropping into the 30's at night, and I I'll be able to let it sit at least a good 2 weeks to cure. I plan on thinning the paint a little, and adding Japan drier to the paint also. Here is a pic of the forecast, do you guys think it'll be OK since I'm giving a lot of drying time?

Myself, I would wait until the temp was closer to 70 degrees to paint. People may have luck at the temps you are forcasting but not me. I like 70 because I feel I can work the paint more. It doesn't clump as bad and it doesn't dry out as bad. I can handle paint at a little higher temp over 70 better than I can at a little lower temp.

Being a professional painter, I would suggest you
go by the instructions on the label of your products.
they are there for a reason.

I continually advocate a 70* temp for a consistant 12 hours.

paint a 1sf test patch - see how it goes.
if it does not satisfy your expectations,
wipe it off with acetone or lacquer thinner
and wait for warmer weather.

what is the humidity factor in your area ?
humidity 50% or higher will yield more favorable results.
below 50% for extended periods of time may not be so favorable.

I am no where near a temperature guru, but, I bet if you
take the temperature of the air and then put an infrared thermometer
to the metal - the metal will be much colder than the air temp. (just thinking here).
If a member here has an infrared thermometer, maybe than can
run this simple test to satisfy the inquiring minds !!!

jus my Dos Centavos

This is what I am trying to describe as a "consistant time period"
for today, starting off at 55* @ 7am then up to 74* @ 4pm then rapidly drops to 50*.
humidity between 35% and 85% would not be a factor as long as the dew point is lower
than the ambient temperature. Meaning if your night time temperature is 40* and your dew point
is 55* - you will get dew on everything. Like on your car. Which is not so good for fresh paint.
(snow on fresh paint is not so good either).

Bottom line is: your boat = your call.





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Johnny, humidity generally stays around 60% here unless a major cold front rolls through, then it drops behind it. Lowest forecasted humidity is 56%. Will adding in Japan drier help me a little on this?

This is an excerpt from an article I wrote a few months ago.
https://www.tinboats.net/varnish-vs-polyurethane/

Drying Accelerator
Japan Drier is a common drying agent that can be mixed with other oils
such as boiled linseed oil and alkyd resin paints and varnishes to speed up
the “drying” or “curing” process. Japan Drier is used by professionals to speed up
controlled drying when they need to apply several coats on the same a day.
Japan Drier is a special blend of lead-free drying agents that accelerates the drying
ability of oil-based paint, enamels, varnish and polyurethane. It is especially effective
in highly humid or cool weather conditions. Although Japan Drier may appear purple,
it will not affect the color of your coating. (varnish or paint). Normally, one ounce
of Japan Dryer per quart of paint or varnish and mix thoroughly. [1:32 mix ratio]
Do not exceed 4 ounces per gallon. Use the minimum recommended amount in white paint
since discoloration may occur in higher concentrations.

thinning with Naphtha: (pronounced Naf-Tha) instead of mineral spirits
will also promote a faster drying time.
when you are ready to paint the whole boat, start your painting project
a couple of hours prior to the highest temp forcast for that day.
placing your boat where it will get the most sunshine will be to your advantage.

Once a thinner or accelerator is added to the mix, it is then called “modified”. do not return
any modified product back to the original container or else it will spoil the whole lot.
so mix up small amounts at a time just to do the job.





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Johnny... Thank you SO much, you've been an invaluable source of both information and confidence in doing all my boats so far.