Shooting Polytone in cool weather.

[Jim Herpst]

They will all crack at some point. No finish is a one and done deal as many would like to think.....

Understand it through real life experience ......was hoping polytone would not crack ...but it does and even if it did not there are too many reviews showing staining and further maintenance issues. I am getting too old to keep screwing around with the finish later.Aerothane is what I am going to use exclusively after research...also realize the differences in a repair but that is not insurmountable. Thanks again.

[Scott]

The reason poly fiber urathanes can be a pita to work with is because they are formulated to remain flexible. This translates into low solids (which is why the reds and some other colours cover poorly).

So, does it work? There are many reasons for cracking, many associated with products and proceedures done before the topcoat.

I recently came across some leftover catalyzed and reduced Ranthane from my Taylorcraft project ie about 8 years old. About 3/8" thick at the bottom of a small open cup. I plucked it out and it had a consistency similar to cured proseal/rtv. Not a scientific study, but certainly more flexible than Jetglow, Awlgrip, ppg, imron which are more user friendly but not approved for polyfiber... some support for the additional hassels asscociated with Polyfiber urathanes perhaps.

Back to the original topic of spraying in cooler conditions, my experience with Ranthane (I suspect aerothane is similar) is that it takes much longer to become tape ready than polyfiber suggests, even at what I would consider to be normal shop temperatures (60-70f).

Wet sanding requires at least 48hours.
Polyfiber states about an hour before fineline tape removal but it's more like 3-5.

Frankly I try not to tape, touch, dismount etc. a finished component for a week as, although the finish is dry, it's still soft and easily damaged (polyfiber say 72 hours)

Doing a "tape test" is no garrentee that tapes won't leave marks after 3-5 hours. Polyfiber manual is conflicting and vague on this point.

Some of this is due to my expectations (fussiness as I get older!) but best advice I can share is just be patient.

Oh and filters these days are made from some kind of synthetic floss that actually adds as much particulate to the air as they remove! (Sounds crazy but its true) If you're creating a diy paint booth, use filters designed for paint booths that have a tack coating applied. This may prevent you from pulling out your hair!

[Jim Herpst]

Scott,

Thank you.for your additional thoughts. My spray booth is the great outdoors. Carefull consideration to days the booth is in use !! I am in South Carolina! I have had good success thus far in the winter months on bright sunny days...read the subject being painted gets heat...ambient air temp not less than 50 and also little to zero wind. Has worked well for me thus far. We will see with bigger panels!!! I

[Ragwing nut]

The reason poly fiber urathanes can be a pita to work with is because they are formulated to remain flexible. This translates into low solids (which is why the reds and some other colours cover poorly).

So, does it work? There are many reasons for cracking, many associated with products and proceedures done before the topcoat.

I recently came across some leftover catalyzed and reduced Ranthane from my Taylorcraft project ie about 8 years old. About 3/8" thick at the bottom of a small open cup. I plucked it out and it had a consistency similar to cured proseal/rtv. Not a scientific study, but certainly more flexible than Jetglow, Awlgrip, ppg, imron which are more user friendly but not approved for polyfiber... some support for the additional hassels asscociated with Polyfiber urathanes perhaps.

Back to the original topic of spraying in cooler conditions, my experience with Ranthane (I suspect aerothane is similar) is that it takes much longer to become tape ready than polyfiber suggests, even at what I would consider to be normal shop temperatures (60-70f).

Wet sanding requires at least 48hours.
Polyfiber states about an hour before fineline tape removal but it's more like 3-5.

Frankly I try not to tape, touch, dismount etc. a finished component for a week as, although the finish is dry, it's still soft and easily damaged (polyfiber say 72 hours)

Doing a "tape test" is no garrentee that tapes won't leave marks after 3-5 hours. Polyfiber manual is conflicting and vague on this point.

Some of this is due to my expectations (fussiness as I get older!) but best advice I can share is just be patient.

Oh and filters these days are made from some kind of synthetic floss that actually adds as much particulate to the air as they remove! (Sounds crazy but its true) If you're creating a diy paint booth, use filters designed for paint booths that have a tack coating applied. This may prevent you from pulling out your hair!

True polyurethane finishes are few and far between. Many are actually acrylic hardened urethanes with flex additives. No matter which, the plasticizers will eventually give up on both at some point.

[3Dreaming]

I think I am going to buy something like this so I can paint in my shop.

https://www.vevor.com/inflatable-paint-booth-c_10313/vevor-inflatable-paint-booth-26x15x11ft-inflatable-spray-booth-high-powerful-750w-950w-blowers-spray-booth-tent-car-paint-tent-air-filter-system-for-car-parking-tent-workstation-motorcycle-garage-p_010233173763

[Jim Herpst]

I think I am going to buy something like this so I can paint in my shop.
https://www.vevor.com/inflatable-pai...p_010233173763

I have a friend that did just that! Good deal!

[Scott]

This is what I've ended up with. I'm suspicious of all of the plastic materials as they so readily get static charged with airflow. Static attracts particles that wait for wet paint to jump into!!! That's how it seems anyway.