Fiberglass prep
Thread Starter
Instructor
Joined: Dec 2001
Posts: 101
Likes: 0
From: Manitouwadge Ontario
Fiberglass prep
I have read hundreds of posts and only have more questions.
My paint is peeling off in sheets. Will post a photo on my site.
I've read everything from fingerprints to greasy hands will cause this. I see so many body off jobs in this form I can't believe that all these bodies are absolutely finger print free. Mine is a mess and I want to do it right. I've ordered Ecklers book. Hope it gets here.
Is there a sealer or something to cover the glass in the event there is an unseen finger print or other "oily" spot?
http://temp.corvetteforum.net/c3/tired74
My paint is peeling off in sheets. Will post a photo on my site.
I've read everything from fingerprints to greasy hands will cause this. I see so many body off jobs in this form I can't believe that all these bodies are absolutely finger print free. Mine is a mess and I want to do it right. I've ordered Ecklers book. Hope it gets here.
Is there a sealer or something to cover the glass in the event there is an unseen finger print or other "oily" spot?
http://temp.corvetteforum.net/c3/tired74
Tech Contributor
Joined: Aug 1999
Posts: 14,379
Likes: 6,390
From: At my Bar drinking and wrenching in Lafayette Colorado
Re: Fiberglass prep (Tired74)
Tired -
Any oil, fingerprint, and any remnant of grease will, in fact, cause a "lift." There is nothing you can use to "cover" oil to promote adhesion. Rather, you simply have to be extremely meticulous when prepping the panels for sealer, primer and paint. I wear a pair of rubber gloves when I wipe everything down so I can't touch any panels with my bare hands. Before applying any primers or paints, I wipe everything down extremely well with wax & grease remover.
Also, before I start sanding, I wipe the whole panel to be sanded down good with the grease remover. This prevents the sandpaper from "grinding in" the oil on the surface.
My body & paint basics paper outlines the part numbers and products to use for the wipe-down and prep process. Drop me an e-mail if you'd like a copy.
V8FastCars@msn.com
Any oil, fingerprint, and any remnant of grease will, in fact, cause a "lift." There is nothing you can use to "cover" oil to promote adhesion. Rather, you simply have to be extremely meticulous when prepping the panels for sealer, primer and paint. I wear a pair of rubber gloves when I wipe everything down so I can't touch any panels with my bare hands. Before applying any primers or paints, I wipe everything down extremely well with wax & grease remover.
Also, before I start sanding, I wipe the whole panel to be sanded down good with the grease remover. This prevents the sandpaper from "grinding in" the oil on the surface.
My body & paint basics paper outlines the part numbers and products to use for the wipe-down and prep process. Drop me an e-mail if you'd like a copy.
V8FastCars@msn.com
Tech Contributor
Joined: Aug 1999
Posts: 14,379
Likes: 6,390
From: At my Bar drinking and wrenching in Lafayette Colorado
Re: Fiberglass prep (BiZ)
Yes - PrepSol works great. It's marketed by PPG/Ditzler. All the other paint manufacturers have similar products for removing grease, and they're a must for proper prep.
Drifting
Joined: Nov 2001
Posts: 1,469
Likes: 6
From: 68 427 4.11s Roadster
Re: Fiberglass prep (lars)
If your paint is coming off in sheets I don't think it was a grease problem. The paint either has to a have a chemical or mechanical bond. If it was painted within the paints "window" it would have chemical bonding. After this window the paint usually needs to be scuffed for the next coat. If it wasn't then the paint is 2 different coats rather than a single attached coat. This may be what is happening to yours.
Lacquer generally remelts to form a longer window in affect but if a long time period elapsed I guess this could happen. The first layer has cured and the next is fresh. This would be like painting over the origanal paint without any prep.
I find nitrile gloves better than latex. They hold up better and don't dissolve with some of the solvents.
Silicon is a heavy duty contaminate for painting also, Remove it before sanding.
Lacquer generally remelts to form a longer window in affect but if a long time period elapsed I guess this could happen. The first layer has cured and the next is fresh. This would be like painting over the origanal paint without any prep.
I find nitrile gloves better than latex. They hold up better and don't dissolve with some of the solvents.
Silicon is a heavy duty contaminate for painting also, Remove it before sanding.
Tech Contributor
Joined: Aug 1999
Posts: 14,379
Likes: 6,390
From: At my Bar drinking and wrenching in Lafayette Colorado
Re: Fiberglass prep (Techno)
Techno is right -
Modern catalyzed primers and sealers must be topcoated within a certain "window" of time in order for good adhesion to occur. If this does not happen, the paint will come off in sheets. GM had this problem on a lot of their cars and trucks in the '80s. If it's sheeting off, it's most likely an adhesion problem. If you're seeing isolated "lifts" and bubbling in spots, it could be contamination. Either way, you've got a lot of sanding and prep to do to fix the problem.... there's no quick or easy fix other than a lot of elbow grease and sweat!
Modern catalyzed primers and sealers must be topcoated within a certain "window" of time in order for good adhesion to occur. If this does not happen, the paint will come off in sheets. GM had this problem on a lot of their cars and trucks in the '80s. If it's sheeting off, it's most likely an adhesion problem. If you're seeing isolated "lifts" and bubbling in spots, it could be contamination. Either way, you've got a lot of sanding and prep to do to fix the problem.... there's no quick or easy fix other than a lot of elbow grease and sweat!
Drifting
Joined: Nov 2001
Posts: 1,469
Likes: 6
From: 68 427 4.11s Roadster
Re: Fiberglass prep (lars)
Both elbow grease and sweat can be cleaned off the body before painting, so use plenty if need be.
Besides this gives you experience for block sanding the final paint.
Besides this gives you experience for block sanding the final paint.
Melting Slicks
Joined: Jul 2000
Posts: 2,107
Likes: 14
From: Lancaster PA
Re: Fiberglass prep (Tired74)
Tired74. I could not access your link so I could not see your pictures. Is it peeling from the glass or is it peeling between coats of primer or color? If it is peeling off of the bare glass it sounds like gasses from paint remover are trapped in the fiberglass. How was the body stripped? What kind of primer-sealer did you use? Craig
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Thread Starter
Instructor
Joined: Dec 2001
Posts: 101
Likes: 0
From: Manitouwadge Ontario
Re: Fiberglass prep (CF6873)
I bought the car as is and all I know it used to be orange and has had 8 owners. It is a rebuild project (restoration word may be used later). I have no idea as to what paint it is. The body seemed to have been sanded as I can see places that were missed. Not to say some sort of chemical wasn't used on the large areas.The paint is lifting beautifully from the fiberglass and not between coats. The car sat under a cover and had a bra on but the lifting is all over. Bubbles and spider web cracks as well. I'll try the link again as I've added pictures. Thanks for the responses. Keep em coming
