Advice/Opinion on Prep for Underwater lights

[cod]

I am installing or will have my marina install (4) Underwater lights. My question is should the bottom paint be removed at the location where the fixture mounts to the hull. Nothing in the manufacturers instructions mentions removing the bottom paint. It only mentions coating the thru hole and the back of the fixture thoroughly with marine grade 4200 sealant.
Im thinking that as long as the bottom paint is sanded and properly adhered to the hull, it should be fine and maybe better to leave it rather than have the bare fibergLass but need some expert advice on this.

 

[Alex F]

Steve, I think there's no question that you'll have to clean it all the way to the fiberglass and roughen the fiberglass to have better "bite". IMO, this is no different then installing a transducer. Make sure to clean the surface very well, wait a little to make sure the solvent is 100% dried and then proceed with 4200. Don't hesitate to use extra. Remember one thing. The components will only get older and will start loosing their affective functionality resulting in a leak. So, in projects like this I put tons of sealant.

Good luck.

 

[gerryb]

I would sand down to the gelcoat and make sure the bonding agent has a clean surface to adhere to...preparation is what will prevent future leaks.

 

[cod]

Thanks guys..... I'm also thinking besides bonding, there may be a "wicking" issue by leaving the paint?

 

[Skuza]

I would say remove the paint. It does wear and wouldn't want it taking the sealant with it. Also I would consider over sizing the holes for the lights and coating it with fiberglass resin. Reason being as I recall someone on here saying once is if the sealant does fail it will not affect the fiberglass or any coring. Just a simple leak that could be re-sealed.

 

[carterchapman]

jemeyedoc put a bunch on his 460 last winter - maybe PM him and see how they did it...