Gel coat gone?

[Professor David]

Looks to me like the gel coat is damaged beyond repair on some panels on my new (to me) rig. See picture attached with the black patterned marks on the right lighter (off white) panel. Wet sanding doesn't remove these black pattern marks. I was hoping to just buff the gel coat to remove oxidation but it looks like I'll need to restore the gel coat or paint. Opinions? Also, what works best gel coat restoration or paint?

 

[Mark_K5LXP]

Depends on your level of expectation and how much you love this thing. There's no magic elixir to just schlup on and wipe off, to prep and gel coat or paint is incredibly time consuming and expensive. Last time I painted a car it was about $3K just for the paint and about a month of prep. An RV would be multiples of that. My arms and back feel sore just thinking about it. I know I don't love my RV that much.

Mark B.
Albuquerque, NM

 

[Heli_av8tor]

My coach exhibits that too. I believe it's microscopic cracks in the gel coat holding moisture that promotes mold.
I've tried numerous products including bleach. I've had the best luck with Honeydew Snow Foam. It seems to penetrate and cleans it off. It will return.

I spray it on with a foam gun attached to my pressure washer.

 

[Matt_C]

I used to do boat work. I saw this sort of thing a lot. It is a tough repair because the GelCoat is applied to the mold and then "the boat" is put inside it. If there is a hiccough anyplace in the process, the laminate does not bond to the surface coat.
When pressed (I didn't like doing it), I would blast the flaking coating off (Like Tom) and then scrub with a cleaner (nasty stuff) and either fill and paint or try to resurface with GelCoat. What ever, it will be difficult and the right materials are expensive....
What the cheap way that is very nearly as good?? Rip off the loose flakes, scrub the area with acetone and then repaint with a linear polyurethane. The rough surface may be visible on close inspection, but it will stay nice looking for a long time.
Matt_C

 

[Professor David]

My coach exhibits that too. I believe it's microscopic cracks in the gel coat holding moisture that promotes mold.
I've tried numerous products including bleach. I've had the best luck with Honeydew Snow Foam. It seems to penetrate and cleans it off. It will return

Thanks. I'll try this.

 

[Professor David]

I spray it on with a foam gun attached to my pressure washer.

Tom, Just wondering if you could give me more details on application? After you spray it on, about how long do you keep in on the surface? Do you wipe or scrub it before rinsing? If so, what do you use to wipe or scrub? Thanks!

 

[Professor David]

I believe it's microscopic cracks in the gel coat holding moisture that promotes mold

You are correct! I put some diluted bleach on the area and the black marks came right off. Left a nice white finish with no black marks (see after picture of same area). Looks like it was mold in micro cracks that the wet sanding couldn't get to. I'll probably do the rest of the coach with a diluted bleach and then wash with the soap. Then get to buffing out the oxidation. Great input Tom!

 

[Heli_av8tor]

I scrub it with a “car wash brush” before it dries. Weather dictates the exact procedure and how long it soaks before scrubbing. If it’s drying too fast I’ll spray it again.
After washing it would likely benefit from a paste wax. However I’m usually worn outside by that time.

 

[TheBar]

I've owned several white vehicles, a boat, and even white painted porch rails get those black spots after the gel coat or the paint starts to dull. I use Walmart bathroom cleaner with bleach if I wait too long. Otherwise if I wash it every 6 months with 1 part Blue Coral Car Wash with 4 parts water it comes off easy with a car wash brush. It leaves carnauba wax on the surface and shines like new. Been using it for over 20 years. I've tried Meguiar's and Mother's car wash/wax and it doesn't last any longer. A year ago Blue Coral was $4 gallon at Walmart. Now it's 17.68? Supply and demand?