Is gelcoat layer needed to make fg waterproof?

[mglyons]

Our '00 Burro had holes in the wheel wells where we assume years of rocks/debris thrown up by tires did the damage. My husband repaired with a few layers of new fiberglass. However we are getting conflicting answers on whether a gelcoat layer is needed over the new fg in order to waterproof. Some have told us that the glass alone is NOT waterproof. Thoughts?

[Bob Miller]

Because it's in the wheel well I would use a heavy coat of undercoating to reduce rock strikes/damage.

[David Tilston]

Fibreglass is water proof.

But I am told it needs to be covered due to ultra violet damage. Your wheel wells are not likely to see much sunlight though.

[CampyTime]

Could you use a spray can type chip guard over the glass? Although I bought a can to do bumper on my chevy, it dries like a rubbery undercoating. Just an idea.


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[Jon in AZ]

Agree with Bob and Wendy. Gelcoat is not needed, but an undercoating is a good idea. Just be sure to apply it when it's thoroughly dry.

[mglyons]

Seems like the consensus is that we are OK without the gelcoat. Thank you for the tips on the undercoating. Wendy, you mention a spray form of chip guard. What is the product name? I want to check it out.

[vintageracer]

Originally Posted by mglyons

Seems like the consensus is that we are OK without the gelcoat. Thank you for the tips on the undercoating. Wendy, you mention a spray form of chip guard. What is the product name? I want to check it out.

3M product.

Call your local bodyshop supply company and tell them you are looking for the lower bodyguard spray product from 3M.

[floyd]

Love this stuff, works well and lasts for years in rough service.
It also sticks to any surface without the need for primer...

[GMike A]

The Dupli-Color is in Lowes and Home Depot and Oreillys . not sure about others. Good stuff.

[CampyTime]

The stuff I was thinking of is similar to what has been posted here, but I got mine from my mechanic who is a NAPA mechanic. It is a black spray can that says "Paintable Rubberized Undercoating." After I take care of the rust on my front bumper and prime, I was going to spray this stuff on before spray painting with a Rustoleum bumper paint. Ran out of time this summer but in the plans for next year. It should help in your situation too; often called "chip guard" as it protects whatever its sprayed on, kind of like a rubbery coating that should deflect road debris for you and keep that area more or less waterproofed, which is what you're looking for.

By the way, my Scamp had been in an accident with the PO and when I took to a reputable gelcoat boat repair guy here he told me that gelcoat is not waterproof. I never went any further with the conversation, and not like me either as I always want to know about how everything works. Must be porous to some degree. Anyway I've seen his work and it was top notch, but alas, I couldn't afford it at the time. Maybe some day!

Best of luck with your project,
Wendy

[Roy in TO]

Then there is Grizzly Grip, you could do the lower front of your trailer at the same time:
http://www.fiberglassrv.com/forums/f...ded-51926.html