Define "Cross Coat"

[N867SP]

I'm getting mixed answers as I search this topic. Shot my first coat of silver today, used just over a gallon (before reducing 4:1) to cover all fabric. The kit comes with 3gal and I picked up a 4th just to be safe. After today I see I only have enough product for 3 single pass coats. So this leads me to believe, that "3 cross coats" is actual 3 coats, 1 east/west, followed by 1 north/south and finally 1 more east/west. Reading poly fiber manual and YouTube videos shows something different, it shows what equates to 6 total coats (1 cross coat = 1 east/west + 1 north/south). So what are other builders doing? Is 3-4gal of poly spray enough to block UV?


Pete
CCK-1865-0078
️N9PW
Severna Park, MD
Sent from my iPad using Tapatalk

[Cubrath]

Pete,

If you look in the back of the polyfiber manual you will see they recommend 11 gal of poly spray for a PA-18 size aircraft.

My understanding of one cross coat is one north-south pass followed by one east-west pass. When I recovered my J-3 I used 8 gal of polyspray. I am planning at least that much for my CC. You will spray two cross coats then sand a fair amount off before the third and final coat. If you spray it to thin you just don't have enough material to sand.


Im guessing the factory can get away with less polyspray because with a professional spray booth they probably don't sand much of that polyspray off.

MR

[ceslaw]

Watching this thread and interested in the answer.

i suspect CC has a different approach than the Polyfiber manual.

wonder what Mitch would say?

[Mitch]

Michael

We do not use the cross coat method. We use a brush to put on all of the tapes before any poly spray get put in the fields. Then we spray all of our poly brush. For the first coat we use a 4" foam brush and brush the poly brush in. Then we put another coat of poly brush on and brush the leading edge again, after that we put one more coat on the leading edge and brush it in. Then we iron all of the edges smooth and apply 2 wet coats of poly spray. This system is lighter and cleaner than lots of poly spray and lots of sanding. You may want to look in DropBox under CCK pictures/cover and review the pictures.

Mitch

[N867SP]

I guess my real question is what have builders that have come before me done? I've laid down my second coat (North/South) and burned up about 1.5gal (before reducing 4:1). Leaning towards ordering up a second 4gal Poly Spray and 1gal R65-75. Has anyone done the "lightbulb test" after only 3-4gal before reducing and if so what were the results? Does the DHUS provide any additional UV protection?


Pete
CCK-1865-0078
️N9PW
Severna Park, MD
Sent from my iPad using Tapatalk

[N867SP]

So I did the 60w lightbulb test after 3 single pass coats...I saw light and ended up ordering 4 more gallons of Poly-Spray and 1 gallon of R65-75 to produce another 5 gallons of reduced product. This will give me another 3 single pass coats for a total of 3 cross coats or 6 single pass coats. Not working in the laboratory condition of a factory I think this might give me the required coverage so I will be able to once again sleep at night. Box showed up from Spruce today so hopefully I will be out of silver this weekend. Allowing a week for all the solvents to off gas for the next week, ready to shoot the PPG Yellow next weekend and get back to building after screwing around with paint!


Pete
CCK-1865-0078
️N9PW
Severna Park, MD
Sent from my iPad using Tapatalk

[Dan L]

I sprayed three cross coats of silver on my EX per the Poly Fiber manual. The downside is some extra weight, expense and time but I too felt more comfortable going this route.

[N867SP]

$500+3hrs over 3days=lifetime of piece-o-mind


Pete
CCK-1865-0078
️N9PW
Severna Park, MD
Sent from my iPad using Tapatalk

[Cubrath]

Pete,

Your progress looks great! You going to spray a white base coat or go straight to yellow?

MR

[N867SP]

Since I'm shooting the PPG, I'm going straight to yellow.


Pete
CCK-1865-0078
️N9PW
Severna Park, MD
Sent from my iPad using Tapatalk