Solution....Grady Mold in Caulk

[Caburke1]

I've owned two new Gradys and have seen many other late model Gradys, all have a problem with mold or mildew forming in the caulk on the gunnels. It get's worse over time. I read all the suggestions for cleaning mold but I haven't found one that works in this instance. Does anyone have experience specifically cleaning the mildew that forms in the Grady caulk?

 

[g0tagrip]

I use strong vinegar......helps but eventually you have to dig it out and redo it.

 

[Fishtales]

I've used mold and mildew cleaners and have the same result. Gotta stay on top of it. The caulk is usually GE Silicone.

 

[seasick]

If the mold is surface mold, it can be cleaned but if it is deeper into the caulk, you may not be able to clean it or it may clean up but mold will come back quickly.
There are some decent mold cleaning products but check that they won't harm your fiberglass or vinyl .
I've had good luck with Mold Off and it works on fabrics also. In mant cases, the product has to sit for a day and may need reapplication but it can get deep mold stains out.
I used to have very good results with ZEP Mold and Mildew cleaner. It is relatively inexpensive and available in the box stores. It doesn't seem to work as good as it did 5 years ago though. I don't know if it's me or if the formula changed. It is still worth a shot.

 

[SkunkBoat]

I "Think" they used something different on the gunnels. We had to take a gunnel off and it definitely was not just silicone. Much tougher and it was prone to mildew too.
We replaced with 4200 and it gets black spots...just like the caulk around the hardtop. We are going to try 4000uv next time we have to mess with it.

Silicone II is great for most things topside and doesn't get mildew but I think they used something that acts somewhat as an adhesive on that piece.

Definitely do NOT use 4200 or 5200.

 

[seasick]

Here is something that might be appropriate but I have no hands on with it.

Pettit | UV Resistant Adhesive Sealant

 

[wlewis]

Get some Soft Scrub with bleach and squirt a line of product over all of the caulking and let it sit for 24-36 hours. Hose it off and most of the mildew should be gone. Works well.

 

[Caburke1]

Thanks wLewis. He suggested using Soft Scrub with Bleach and letting it soak in. I ran a "bead" of the Soft Scrub covering the moldy caluk, let it sit overnight, hosed it off the next day and 100% of the mold was gone. This was a month ago and I've seen no bad side effects yet.

 

[grady33]

i use this everywhere on the boat. works wonders but need to stay ahead of mold.