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  #1  
Old 09-14-2019, 12:11 PM
Stockmanreef Stockmanreef is offline
 
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Location: Midland, mi
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Default Priming wheel pants

I am at the point where I should prime the wheel pants. Will primer stick well to the gel coat on the parts or does this have to be scuffed up prior to priming?

Thanks
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  #2  
Old 09-14-2019, 01:20 PM
Nova RV Nova RV is offline
 
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Wash with water to make sure the release agent is all removed then sand with 320 or 400 then wax and grease remover and prime.
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  #3  
Old 09-14-2019, 01:22 PM
MED MED is offline
 
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Priming should be done just before painting, so I only put primer on the areas where I applied Fiberglas - to protect the epoxy from UV. I left the rest of the gel coat intact for the paint shop to prime and paint.
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Last edited by MED : 09-14-2019 at 01:27 PM.
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  #4  
Old 09-14-2019, 01:28 PM
Nova RV Nova RV is offline
 
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Quote:
Originally Posted by MED View Post
Priming should be done just before painting, so I only put primer on the areas where I applied Fiberglas - to protect the epoxy from UV. I left the rest of the gel coat intact for the paint shop to prime and paint. ��
Remember too that the outer grey layer on the newer fiberglass parts is just tinted epoxy and has no UV protection so if you are going to fly a while prior to painting, a coating of epoxy primer over all of the grey parts would be the best protection.
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  #5  
Old 09-14-2019, 02:26 PM
wilddog wilddog is offline
 
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Location: va.
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You should fill air the pinhole before primer. Search this site for methods, Dan Horton had a good post on that. Read your OP and noticed you have jel coated parts.You may not have any pinholes, count your blessings.

Last edited by wilddog : 09-14-2019 at 02:29 PM.
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  #6  
Old 09-14-2019, 02:59 PM
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bkervaski bkervaski is offline
 
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Quote:
You should fill air the pinhole before primer. Search this site for methods, Dan Horton had a good post on that. Read your OP and noticed you have jel coated parts.You may not have any pinholes, count your blessings.
There are definitely pinholes in the gel coated parts .. you can't really see them until you have sprayed primer then they start sticking out like sore thumbs
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  #7  
Old 09-14-2019, 03:24 PM
lr172 lr172 is offline
 
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Quote:
Originally Posted by bkervaski View Post
There are definitely pinholes in the gel coated parts .. you can't really see them until you have sprayed primer then they start sticking out like sore thumbs
+1

I was very disappointed in these parts. After sanding, the gelcoat had no pinholes. However, the gel coat was too thin. After spraying primer, 1000s of pinholes appeared, as the gel coat was too thin and broke down with the primers solvents.

Larry
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  #8  
Old 09-14-2019, 03:26 PM
lr172 lr172 is offline
 
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Quote:
Originally Posted by Nova RV View Post
Remember too that the outer grey layer on the newer fiberglass parts is just tinted epoxy
Pretty sure that is not the case. It is gel coat and they are typically a 2K polyester, possibly a urethane.

Larry
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  #9  
Old 09-14-2019, 03:35 PM
Nova RV Nova RV is offline
 
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"Gel coat" is typically used only in polyester layups and the wheel pants are epoxy. The grey coating on the outside is a layer of colored epoxy and most likely thickened to minimize pinholes. The colored epoxy layer is not a polyester "gel coat" even though people refer to it as such. Treat the grey layer as you would a non tinted part meaning it needs a protective coating (primer as a minimum) for any UV protection. You can always tell polyester by the smell.

Just to explain more, the pin holes you see are simply voids in the outer layer where it does not fill the cloth weave underneath. This can be from using an initial layer of cloth that has a coarse weave or an initial layer of glue not thickened enough to prevent the voids from showing. Either way, the glue doesn't fill the weave and you have a pin hole. Typically a layup would have a thickened coat of glue put down first and allowed to partially cure so it stays sticky but gooey enough to fill all of the voids in the first layer of fiberglass cloth to minimize pinholes. Of course a vacuum bag process if used should get all of the air out and then push the glue into every void preventing pin holes for the most part but not all parts are vacuum bagged when produced.
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CFI-I ASMEL, ATP

RV-14A kit # 140243 (flying as of 11/18)

www.mykitlog.com/chrismoon/

Last edited by Nova RV : 09-14-2019 at 03:55 PM.
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  #10  
Old 09-14-2019, 05:40 PM
Stockmanreef Stockmanreef is offline
 
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Location: Midland, mi
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will "Filler Primer" take care of the pin holes?
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Midland, MI
EAA Chapter 1093 member

FaceBook Page: Ken's RV-14
RV-14a (serial number 140073)
N73XP

Plane at hangar and the wings ON.
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