Does my Achilles have the measles??

Jimmy Buoy

Well-Known Member
Dec 3, 2008
2,454
Sarnia, Ontario, Canada
Boat Info
2003 Cobalt 293
Engines
Twin Volvo-Penta 5.0 270hp & DuoProps
At the boat show, a guy told my buddy that acetone was the strongest thing to use on Hypalon. Get verification, and he did say they used it as "Professionals," but it may help your acne. Do you use a cover on your dinghy? May help.
 
Looks like mold to me. I've used Tilex before with tough to remove mold on fibreglass, however I'd be nervous about it damaging or degrading the Hypalon. There is a non caustic mold remover available at Home Depot (Concrobium Mold Control) that might be worth giving a try.

Paul
 
At the boat show, a guy told my buddy that acetone was the strongest thing to use on Hypalon. Get verification, and he did say they used it as "Professionals," but it may help your acne. Do you use a cover on your dinghy? May help.


No cover - that's why I spent the extra $$ for Hypalon. I have tried acetone without any sucess. The marks seem to actually be under the surface.
 
i have the same thing on parts of my Avon (color white) dink. I have tried Tilex and other products to remove this. It works a bit, but never gets everything off. In fact, I am at the point of trying some topcoat for the dink. I purchased MDR Topcoat in white color to restore the look. Just waiting for the weather to get warmer... Note to self.... NEVER-EVER buy a white dink again!!! LOL.
 
I've got the same thing on my Hypalon AB dinghy and tried a lot of different cleaners with little luck. A friend suggested making a mixture of water and bleach, soaking a rag in it and laying the rag over the affected area and letting it stay there for 5-10 minutes. I got rid of a lot of the mold spots but not all of them and it did lighten the spots that remained. Maybe it will work for you.

On a different subject Jimmy, how do you like the trim tabs on your dinghy? I've got a 10 RIB with a 15 Yamaha. She does alright with 2 of us once it's on plane but getting there takes a lot of leaning forward to get the bow down. I was thinking of adding a set of Smart Tabs this year to see if it helps.
 
I've got the same thing on my Hypalon AB dinghy and tried a lot of different cleaners with little luck. A friend suggested making a mixture of water and bleach, soaking a rag in it and laying the rag over the affected area and letting it stay there for 5-10 minutes. I got rid of a lot of the mold spots but not all of them and it did lighten the spots that remained. Maybe it will work for you.

On a different subject Jimmy, how do you like the trim tabs on your dinghy? I've got a 10 RIB with a 15 Yamaha. She does alright with 2 of us once it's on plane but getting there takes a lot of leaning forward to get the bow down. I was thinking of adding a set of Smart Tabs this year to see if it helps.

Got these tabs last year and they really work well. For an 8.5' Dingy with a 5Hp motor, it gets up on plane with me and my wife on board (without leaning forward). It will even stay on plane at 1/2 throttle, although it makes quite a wake doing so! The only down side is that the top of the tabs can really get a lot of marine growth since they're just under the surface of the water and get lots of sun. They are easily removable to clean anyway.

Without the tabs there was no way to get the dingy on plane with us aboard. Even with just me, I had to lean way forward - so it's a huge difference in my scenario.
 
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On the tabs subject, what brand are the ones you are using?
 
I've got the same thing on my Hypalon AB dinghy and tried a lot of different cleaners with little luck. A friend suggested making a mixture of water and bleach, soaking a rag in it and laying the rag over the affected area and letting it stay there for 5-10 minutes. I got rid of a lot of the mold spots but not all of them and it did lighten the spots that remained. Maybe it will work for you.

On a different subject Jimmy, how do you like the trim tabs on your dinghy? I've got a 10 RIB with a 15 Yamaha. She does alright with 2 of us once it's on plane but getting there takes a lot of leaning forward to get the bow down. I was thinking of adding a set of Smart Tabs this year to see if it helps.

I did a video of the effect of Maxi Marine tabs on my Mercury 310 fiberglass bottom RIB with 8hp Yamaha. They made a huge difference. It would plane with two before, but nothing like now. I am 200 lbs and my son (driving) weighs about 140. (and on the topic if the post,I have found that fantastic spray version with bleach, with a stiff brush and a LOT of elbow grease takes it off on mine).

Here is the dink video.

[video=youtube;Zjhc4T7kExw]http://www.youtube.com/watch?v=Zjhc4T7kExw[/video]
 
I have the same problem with my Mercury Amanzi. It looks like the spots are in the fabric, not on the fabric, if you know what I mean. I've tried everything I can think of but the only thing that made a difference was acetone. Only problem is that the acetone removes some of the material so I only did a small spot and decided it was to dangerous to do any more. I was thinking about going the paint route but have read on the RIB forums that it's a bad idea. I really want to do something about it because it's embarrasing. Hopefully someone will come up with a cure. Maybe we can get funding from the government for research! Mark
 
My hypalon had a simular look, just not as bad on the grey dink. I used MEK to clean it, its some nasty stuff but took off the black stains. I am considering a tuff coat and they recomend using MEK to clean before brushing their sealer coat on the dink. I have a couple of pics but not a good pic of the stains before I started.

An old pic from 4 or 5 years ago, hard to see the stains but they are there

IMG_0383.jpg


PIC after the cleaning with MEK. Working on a few pinholes now...

IMG_2119.jpg
 
If it is mold, try some type of oxygenated cleaner such as Oxy-Clean.

I had the same issue on a white Avon. The round mold spots will in time turn to a pock where the mold eats away at the organics of the fabric causes a lot of dimples.

I did the following to try to keep it under control.

Using hot water make up a poultice of Oxy-Clean powder it should be paste like, spread it on the surface in 1 x 1 foot areas, then cover quickly with plastic wrap and tape it down burping out the air. Repeat in new squares as close as you can get them. Leave on over night, remove and throughly rinse. While wet, apply a chlorine based mold remover spray and allow to dry, repeat and repeat. until the mold has disappeared, scrub with a white 3M scrubbing pad and soft scrub rinse and let dry. When dry it should be deciodedly cleaner, most mold lightened and you've got the best it will be.

If you want to get aggressive, on a dry surface, hand scrub with MIK (I Mean MIK) solvent soaking rags. Do this in the open air away from flames and anything that sparks. Wear respirator in closed spaces. Work the MIK solvent rapidly changing rages each time the rag dries.

Do this step before before the soft scrub final clean up.

(MIK = Methyl Isobutyl Ketone, this is used as a solvent in vinyl paints and finishes inc. vinyl bottom paints. This stuff will flash rapidly like Laquer thinner, to slow it down mix in 5-10% Xylol/Xylene, and if still flashing to quickly a table spoon of clean mineral spirits to a half gallon mix. The idea is to slow down the flash off so the MIK can penetrate and clean out the deep pores.)

You've now taken two days of your life, spent 150 bucks in cleaners etc, fighting mold that will be back in a week if you don't get a cover for the thing. No cover prepare to scrub that dingy every month. If you don't want a cover, then add to the supplies list a really good vinyl sealant, $30. a quart probably, and apply several coats. That will get you maybe a month without a cover.

For a source of the sealant, see BOW our host here.
 
As Chad mentioned if you use MIK (MIBK?) or MEK make sure and protect yourself. I cleaned mine outdoors in the shade at 6 AM taking several breaks between cleaning a small area.
 

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