Finishing, trick question

[Willemjm]

Spraying pre cat in the shop, with a big fan and filters pulling clean air in and pushing the overspray and fumes out.

Yesterday, very humid, the air pulled in is not conditioned, but all is going well and the base coat is sprayed over the primer coats. Big job.
Finish the base coat around 6:00pm and starting to close the shop, switch off the fan, everything is curing. The next day, (today) is planned for final spraying with some remaining base coat and a clear coat over the solid color base coat. Wifey comes in and says you should switch on the AC, will dry the air overnight and help with curing. So I switch on the AC at 68F and close up. Today, I opened the shop at 8:00am, nice and cool, set up for spraying and started the big fan to get the air moving through the shop. It is humid again today. Sprayed some of the final base coats and then finished everything with a clear coat.

So was it a good idea to run the AC at 68F, dehumidify the shop and bring the temperature inside down to 68F overnight, or was it a bad idea?

 

[PeteM]

Spraying pre cat in the shop, with a big fan and filters pulling clean air in and pushing the overspray and fumes out.

Yesterday, very humid, the air pulled in is not conditioned, but all is going well and the base coat is sprayed over the primer coats. Big job.
Finish the base coat around 6:00pm and starting to close the shop, switch off the fan, everything is curing. The next day, (today) is planned for final spraying with some remaining base coat and a clear coat over the solid color base coat. Wifey comes in and says you should switch on the AC, will dry the air overnight and help with curing. So I switch on the AC at 68F and close up. Today, I opened the shop at 8:00am, nice and cool, set up for spraying and started the big fan to get the air moving through the shop. It is humid again today. Sprayed some of the final base coats and then finished everything with a clear coat.

So was it a good idea to run the AC at 68F, dehumidify the shop and bring the temperature inside down to 68F overnight, or was it a bad idea?

Good idea

 

[Craptastic]

I used to work at a high end door plant in the finishing department. Company policy was always spray in whatever environment (as long as there wasn't fog in the shop or the sprinklers on) and let the paint setup in a dryer environment (we had airconned rooms we wheeled the doors into). No spraying in the drying rooms, and no spraying excess inventory that couldn't fit into the drying rooms if the humidity, in the shop where they would be parked, was going to exceed 75% in the next 12 hours. It seemed to work well and they had taken years to develop such a system.

So, in short, your wife suggested it and it appears to have worked well. Then you've done well.

If it didn't work, I'm sure you did something wrong somewhere else along the way.

 

[Graywolf]

Anything you can do to reduce the moisture in the environment is helpful. Your wife is a smart lady.

 

[Berta]

When I worked in the finishing department of the factory there was no air conditioning. There was no heat except the strip heater on the ceilings. And the heat from the ovens. Everything was sent through ovens to aid and speed drying and curing time.
So my experience says, No, warmth is good.

 

[LocoWoodWork]

Condensation?

 

[drw]

If the finish turned out well, it was a great idea; if it turned out poorly, it was someone else fault!

 

[Willemjm]

Condensation?

You got it.

I started spraying the last few base coats this morning and they blushed from condensation. Humid 78F air in contact with 68F pieces produced condensation right away.

Then I started noticing condensation on all the surfaces of my machines in the shop.

It all turned out good though, because when I started spraying clear coats the temperatures in the shop were stabilized.

I will have to clean all my machine surfaces in the shop though and re-wax them as the corrosion is showing.

We never stop to learn, do we.

 

[AllanD]

I can certainly see that happening as humid as it is. I feel your pain, it is really a confounding problem for me to suck all the outside air through the finishing room and flush out all the conditioned air. My fan pulls 13,000 CFM. But I just can't put off finishing until fall. One thing that might be saving me is that I use water based finishes whenever I can so may just dry slower but no blushing like a lacquer. Most cabinets I have done are white so I use the Key Aqua plus.

 

[gamiller3rd]

You got it.

I started spraying the last few base coats this morning and they blushed from condensation. Humid 78F air in contact with 68F pieces produced condensation right away.

Then I started noticing condensation on all the surfaces of my machines in the shop.

It all turned out good though, because when I started spraying clear coats the temperatures in the shop were stabilized.

I will have to clean all my machine surfaces in the shop though and re-wax them as the corrosion is showing.

We never stop to learn, do we.

Maybe an a/c setting closer to the overnight ambient temperature would work better keeping the humidity down but eliminating the condensation factor. Or possibly your unit has a “dry” setting? Keep us posted thanks.

 

[FredP]

I have a window unit for AC. It only runs when I need it to. However I have a dehumidifier running 24/7 to keep the shop dry. I never open up the shop when finishing. I open up after the Finnish is dry. If another coat is needed I close up and let the dehumidifier do its thing before I recoat. Dehumidifier is set to 45-50%
Edit to add. Water Bourne Finnish will blush too. DAMHIKT.

 

[Skymaster]

in my shop a/c runs 24/7 set at 72. No humidity, solid temp, finish shop humidifier 24/7, if I am using it than night before I turn a/c on when I get in everything is stabilized and ready to go. Humidity above 70% is normally the nogo point.