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  #1  
Old 09-09-2021, 07:59 AM
Reflex Reflex is offline
 
Join Date: Jan 2015
Location: Kansas
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Default Question on EXTERNAL primer (UV issues?)...

I probably should have asked this question before completing much of my fiberglass work. Perhaps I can solve that potential problem from here to the end.

I'm planning to fly off my phase I before paint. I'd like to use a primer that has good UV resistance. What are you using for primer that has good/excellent UV resistance? Can't seem to find much data on it.

Thoughts?
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  #2  
Old 09-09-2021, 08:15 AM
John Tierney John Tierney is offline
 
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You probably won't find much info on UV resistance to primers since it is not intended as a top coat.
Like you I flew for over a year with bare metal and fiberglass primed. I used PPG Omni line products on the fiberglass: (1) Omni MP 170 Epoxy Primer, over (2) Omni MP 282 High Build 2K Urethan Primer Surfacer.
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  #3  
Old 09-09-2021, 10:29 AM
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acam37 acam37 is offline
 
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Donít prime until you are ready to paint. If you do prime and wait a considerable amount of time then you will have issues with the top coat bonding. Some primers have a window of time that the top coat has to be applied.
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  #4  
Old 09-09-2021, 12:31 PM
jacoby jacoby is offline
 
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SPI Epoxy primer has UV-resistance but it requires up to 4 hours of induction time. See their TDS. I've used it quite a bit with great results. It'll actually go on glossy and stay that way if you don't scuff it.

If you go longer than 30 days to topcoat you have to sand with 180 and prime again before moving forward.
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  #5  
Old 09-09-2021, 02:42 PM
lr172 lr172 is offline
 
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Quote:
Originally Posted by jacoby View Post
reat results. It'll actually go on glossy and stay that way if you don't scuff it.

If you go longer than 30 days to topcoat you have to sand with 180 and prime again before moving forward.
chemical bonding window on SPI epoxy primer is 7 days, NOT 30. after 7 days, it must be scuffed and another coat of primer added.
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  #6  
Old 09-09-2021, 04:44 PM
jacoby jacoby is offline
 
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Quote:
Originally Posted by lr172 View Post
chemical bonding window on SPI epoxy primer is 7 days, NOT 30. after 7 days, it must be scuffed and another coat of primer added.
I was simplifying things. You get 7 days without any additional prep. 7-30 days sand with 180 and then topcoat. After 30 itís sand with 180, prime, and then topcoat. The chances of getting through phase 1 and painting within 30 days are super slim.
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