Exposed fibers - old fiberglass

[mylo]

There are two fiberglass sections on my old class C that are now showing exposed fibers. I assume that I can just paint on another few coats of gel coat to re-bury them?

A couple of questions... Regarding prep - I suppose a light scuff sanding will be needed to remove surface oxydation and improve bonding, yes? That will remove much of the surface fibers, but I also assume that is not a big deal. And two - is there a special formulation with a longer "open" time, that will smooth and "level" better with a tight nap roller application? Or am I going to have to figure out how to spray this stuff?


Thanks.

Mylo

 

[driftless shifter]

if it's that old and you're on a budget, look into boat paint. clean and sand the surface first to get rid of stray fibers and to give the paint some tooth. ''interlux brightside'' or ''pettit easypoxy'' are two that i have used. applied with a foam roller and tipped in with a quality brush. done right it self levels and the brush marks mostly disappear.

classic westfalia folks have had great success with vintage vw pop-tops using this stuff.

 

[mylo]

if it's that old and you're on a budget, look into boat paint. clean and sand the surface first to get rid of stray fibers and to give the paint some tooth. ''interlux brightside'' or ''pettit easypoxy'' are two that i have used. applied with a foam roller and tipped in with a quality brush. done right it self levels and the brush marks mostly disappear.

classic westfalia folks have had great success with vintage vw pop-tops using this stuff.

Awesome, thanks! I bet that will work just fine.


Mylo

 

[Gary RV_Wizard]

You can't "paint on" gel coat, but you can use epoxy paints and you can fill any gouges or exposed fibers with standard automotive fiberglass body putty (aka "Bondo") before painting. You can also buy gel coat repair kits for patching surface holes, but I wouldn't bother trying that if I were going to paint anyway. It's primarily for cosmetic patching of glossy areas.

 

[bucks2]

Understanding the cause of the exposed glass fibers might keep you from getting more. The resins used to bond the glass fibers that we commonly call fiberglass have little or no UV resistance. Therefore, gel coat or "full body paint" is used to provide UV protection. When the paint or gel coat has worn thin, thru constant polishing or utter neglect (both wind up in the same place, the difference is the amount of time it takes to get there) then the resin degredates (oxidizes) and the glass fibers are exposed.

So, painting the surface and replacing the UV protection for the remaining fiberglass is in order. Sanding loose material away is recommended, however remember that the surface and maybe even the subsurface you are working on is damaged so you won't get a perfect surface just by sanding. Primer and surfacer will be needed to get a reasonable painting surface. Once you've repaired the surface appropriately, you will have to decide between a variety of topcoats. One part and two part polyurethanes, both easily found at marine stores in a variety of colors are probably the easiest way to go. Remembe that the topcoats are relatively thin and transparent compared to house paint so a well primed surface is essential. A roll and tip procedure will probably give you the smoothest surface. There are many websites which describe the process in detail.

Ken

 

[mylo]

Understanding the cause of the exposed glass fibers might keep you from getting more. The resins used to bond the glass fibers that we commonly call fiberglass have little or no UV resistance. Therefore, gel coat or "full body paint" is used to provide UV protection. When the paint or gel coat has worn thin, thru constant polishing or utter neglect (both wind up in the same place, the difference is the amount of time it takes to get there) then the resin degredates (oxidizes) and the glass fibers are exposed.

So, painting the surface and replacing the UV protection for the remaining fiberglass is in order. Sanding loose material away is recommended, however remember that the surface and maybe even the subsurface you are working on is damaged so you won't get a perfect surface just by sanding. Primer and surfacer will be needed to get a reasonable painting surface. Once you've repaired the surface appropriately, you will have to decide between a variety of topcoats. One part and two part polyurethanes, both easily found at marine stores in a variety of colors are probably the easiest way to go. Remembe that the topcoats are relatively thin and transparent compared to house paint so a well primed surface is essential. A roll and tip procedure will probably give you the smoothest surface. There are many websites which describe the process in detail.

Ken

Thanks, Ken. Can you elaborate on this "primer and surfacer"? The one part polyurethane top coat suggested above turns out to be 1.5 mils per coat. I'll probably put a couple on. It's a 20 yr old coach that seems to have plenty of life left in it, with some TLC. That being said, I don't want to fill this proverbial hole with money. If I can get another 5 yrs out of it without spending a ton of money and time on it (instead of using it), that would be great.



Mylo

 

[bucks2]

Primer/primer surfacer is a matte coat paint that is highly pigmented to produce a uniform opaque surface which sands easily, and is designed to fill any minor imperfections and sand scratches. This is used after any bondo filler and glaze putty fills the majority of the imperfections.

Primer is typically an older school product which can shrink and can be "reflowed" when the solvent used in topcoats melts it. Primer/surfacer is typically a more modern formula which is less likely to shrink over time as the solvent evaporates and is much less likely to reflow from the topcoat solvent.

With good preparation and priming, two coats is the minimum you'll want to apply. Even at $40 per quart (or so) the majority of the work is the prep and masking. A third coat is a minimal amount of work and well worth the effort IMHO especially for a surface where the resin has oxidized as much as yours.

Watch carefully how much paint you allow to build up on the tape lines and don't forget to pull the tape after the last coat skins over. Waiting for it to dry fully before pulling the tape will result in hard lines and frustration trying to get the tape off. Don't skimp on tape quality by using the old tan stuff. Absolutely use either blue "long mask" or even the green fine line long mask.

Ken

 

[Just Lou]

Just how serious is this "exposed fiber" problem?  Are they just very evident as fibers or are they actually fraying and flapping in the breeze?  Photos would certainly help in suggesting a remedy.  Especially concerning the age and relative low value of this RV.

I think I know what I would do, but I'll not make a recommendation without having a good view of the actual problem and expected result.

 

[mylo]

Just how serious is this "exposed fiber" problem?  Are they just very evident as fibers or are they actually fraying and flapping in the breeze?  Photos would certainly help in suggesting a remedy.  Especially concerning the age and relative low value of this RV.

I think I know what I would do, but I'll not make a recommendation without having a good view of the actual problem and expected result.

I'll see if I can snap a picture tonight.


Mylo

 

[Sloop]

Lou,
Not sure when Mylo is getting back with the pictures but I would be interested in what you were going to suggest.  On my Class C I can see the fiberglass fibers on the overhang if the sun hits them in just the right position.  On a gloomy day it is not obvious.  None are "flapping in the breeze".  I had one person tell me I need to address it but my feeling is it is caused mostly from the wind hitting the curve of the overhang over the years and not worth attacking unless fiberglass fibers are actually separating or breaking. The overhang is the only place on the coach that displays this wear.
Thanks,

 

[Just Lou]

Not sure when Mylo is getting back with the pictures but I would be interested in what you were going to suggest. 

I sent you an e-mail

 

[mylo]

Here are some horrifying pictures of the damage... furry, indeed. I still think that some sort of topcoat should still work. At this point in the coaches life, it's not worth going nuts on full restoration, but maybe just doing a few things to keep this operational for a few more years.







Mylo

 

[bucks2]

Sloop, if you're seeing the chopped glass fibers then you should put some type of UV protectant on there to slow the degredation. Even something as simple as 303 protectant will slow or stop the loss of resin holding the fibers and make it last longer. Paint would be a good long term solution but it sounds as if you might be talking a fairly small area and matching could be a problem.

Ken

 

[Just Lou]

I'm having trouble believing this is actually damaged fiberglass.  It looks almost intentional.

I'm not a fiberglass expert, but I've never seen RV side panels with such large, random and course glass fibers.

In looking at photo #1, the area around the orange clearance light looks smooth.  Unless this is just an illusion, that would indicate it was designed in.

The areas in the remaining photos appear very uniformly textured, even right up to (and presumably under) the edge of the window frame.

This gets curiouser and curiouser all the time.

 

[Sloop]

Ken,
Mylo's fiberglass is about ten times more coarse than mine so I am thinking a little UV protection may be just fine.  I think Lou may be right about Mylo's fiberglass.  It appears to have been manufactured with a coarse surface.  If he has broken fibers extruding I would sand it and coat it with a UV protectorant.  No need for a thousand dollar repair to a ten dollar problem.

 

[Alfa38User]

I would coat it with Gelcoat (the outer coat as found on a boat). It can be painted on nicely and can be purchased through many marine dealers. Epoxy resins (paint) may be affected by ultraviolet light although I once found a  very nice smooth epoxy fairing filler that went on like body putty but needed a paint on it afterwards.

 

[meternerd]

I had an older class C with a lot of yellowing and some fibers showing.  I stripped off the old striping, sanded and cleaned the surface, applied STIX primer (designed to stick to fiberglass) and applied white acrylic exterior enamel over that.  Used an airless sprayer to apply it.  Put new decals on and it still looked great 4 years later.  I live near Lake Tahoe at 6200' and UV never did any damage at all.  Sold it last year and bought a new (used) one that's larger and newer.

 

[jmugs]

I used to have an old fibreglass dune buggy body that looked like it was covered with cat hairs. It was just a beater toy that I didn't wanna spend much on. I gave it a good wet sanding and a couple coats of Flood's Penetrol using paint pads. It came out pretty darn good. I don't know about the UV factor, but it lasted for the next couple years we were beating the daylights out of it. I was impressed with how the color came back alive eventho it didn't look like a show finish up close.

Might be worth a try if you don't wanna spend a bunch.