Black stuff all over a boat?

[Ted10028]

when I look inside the bilge or a locker ,
around the engine floor etc most of what was once the dull white gelcoat or finish now has black mixed in with it. The surface
is pretty rough so intense cleaning only does so much. I'm thinking of a prime coat like Kilz. Any thoughts?

 

[thinwater]

I think you can probably do a lot better at cleaning than you think, with the right products. Painting over dirt and mildew is always bad, even with a good primer. Unlike wood, the mildew is not deep in the fiberglass and you should be able to get it.

Try scrubbing with a good hard surface cleaner. Spic and Span, Fabuloso, Spray Nine, or even a TSP/borax blend. Then bleach with a 30-60 minute dwell. Use the cleaners at the recommended dose; over concentrating does NOT increase effectiveness in many cases, and some cases, like bleach, it can actually make them less effective.

A very stiff scrub brush helps a lot. I've never found a gelcoated locker I could not clean. It's about the chemistry, the right steps, and the right brush.

Just remember, if the gel coat mildewed, the paint will mildew faster. And bilges were never meant tot be shiny white for long.

 

[jssailem]

Give it a good cleaning and scrub down. Soap & water. It could be carb

TSP is often used as preparation for painting. Use personal protective gear when using TSP.

What Is Trisodium Phosphate?

Is trisodium phosphate (TSP) the right choice for your cleaning project? Get the pros and cons and how-to info about TSP here.

www.thisoldhouse.com

 

[Ted10028]

I think you can probably do a lot better at cleaning than you think, with the right products. Painting over dirt and mildew is always bad, even with a good primer. Unlike wood, the mildew is not deep in the fiberglass and you should be able to get it.

Try scrubbing with a good hard surface cleaner. Spic and Span, Fabuloso, Spray Nine, or even a TSP/borax blend. Then bleach with a 30-60 minute dwell. Use the cleaners at the recommended dose; over concentrating does NOT increase effectiveness in many cases, and some cases, like bleach, it can actually make them less effective.

A very stiff scrub brush helps a lot. I've never found a gelcoated locker I could not clean. It's about the chemistry, the right steps, and the right brush.

Just remember, if the gel coat mildewed, the paint will mildew faster. And bilges were never meant tot be shiny white for long.

I am thinking that while I could clean it and maybe even get 90% of it the 10% remaining will simply begin to propagate again whereas the primer pictured is designed to paint over it and kill it for a long period of time.

 

[Leeward Rail]

Clean it correctly and it won't be a problem.

Paint isn't a solution to cleaning dirt or even mold, on a boat. Painting over dirt and mold on a boat is like painting a car instead of washing it.

The reason zinzer is used in a building environment, is that you can't fully clean drywall. Cigarette smoke, grease, mold gets right into the paper and gypsum material.
Your boat isnt made of drywall.

Cleaners and in extreme cases a pressure washer does wonders. (Pressure washing the lockers, engine, etc is the first thing I did with our current boat)

If the boat is in the water, a shopvac will suck the water and debris out of the bulge and allow dumping the water ashore (disconnect the bilge pump so it doesn't get pumped into the water)

Fully clean it first...and then.. if the surface is permanently discoloured enough that you care about it, . use marine paint.

 

[Tally Ho]

My engine bilge was terrible…dirty and dark. The original blue O’Da bilge paint was flaking off all over the place,

I scrubbed it with several cleaning solutions, even sanding it down in some really rough areas.

Then I painted it with a couple of coats of Bilge Kote (or something like that).

It made a huge difference in brightness and keeping the bilge clean. Still holding up pretty well.

Before…


After…


To be fair, I also replaced the shaft, and upgraded the shaft seal to a Volva Penta dripless, which also helps and opened up some space in the bilge.

Greg

 

[Scott T-Bird]

when I look inside the bilge or a locker ,
around the engine floor etc most of what was once the dull white gelcoat or finish now has black mixed in with it. The surface
is pretty rough so intense cleaning only does so much. I'm thinking of a prime coat like Kilz. Any thoughts?

You may be talking about at least 2 different issues. First of all, mold doesn't grow on inorganic substrates, so a mold killing product isn't really applicable to fiberglass and gel coat. The pan under your engine and the wall on the port side of the engine has a gel coat finish, which is much smoother than the fiberglass finish in the bilge and all the lockers. I had a lot of dark grungy stuff around my engine when I bought the boat (I actually had some trepidation over buying the boat when I saw it on my first visit). I think it was a combination of oil and belt dust and the previous owner was not much of a house keeper. I cleaned most of it off but it's not perfect and I just live with it. But the last thing I want to do is paint over gelcoat. In my opinion, painting over gelcoat is much uglier than leaving a little bit of the discoloration. I removed spray paint that the previous owner thought was a good idea on the pedestal under the toilet because it was horrid. It is much better now that the gel coat is renewed.

Painting the fiberglass surfaces in the bilge and lockers is a good idea if you really need to or want to. Just use the bilge kote product. You are not dealing with mold in those areas. It's just grime and probably some oil in the bilge, which makes it particularly pernicious to clean up.

 

[Ted10028]

You may be talking about at least 2 different issues. First of all, mold doesn't grow on inorganic substrates, so a mold killing product isn't really applicable to fiberglass and gel coat. The pan under your engine and the wall on the port side of the engine has a gel coat finish, which is much smoother than the fiberglass finish in the bilge and all the lockers. I had a lot of dark grungy stuff around my engine when I bought the boat (I actually had some trepidation over buying the boat when I saw it on my first visit). I think it was a combination of oil and belt dust and the previous owner was not much of a house keeper. I cleaned most of it off but it's not perfect and I just live with it. But the last thing I want to do is paint over gelcoat. In my opinion, painting over gelcoat is much uglier than leaving a little bit of the discoloration. I removed spray paint that the previous owner thought was a good idea on the pedestal under the toilet because it was horrid. It is much better now that the gel coat is renewed.

Painting the fiberglass surfaces in the bilge and lockers is a good idea if you really need to or want to. Just use the bilge kote product. You are not dealing with mold in those areas. It's just grime and probably some oil in the bilge, which makes it particularly pernicious to clean up.

The previous owner of my boat apparently had painted the underside of all the locker covers. It all was peeling very badly and it turned partially black. it took about 15 minutes per cover for me to wire brush , sand , acetone and paint the undersides . what was once very ugly and embarrassing is now pristine. If it lasts five years I will consider it a victory.

 

[thinwater]

I am thinking that while I could clean it and maybe even get 90% of it the 10% remaining will simply begin to propagate again whereas the primer pictured is designed to paint over it and kill it for a long period of time.

The correct cleaners (TSP, borax, and bleach) will kill all of it. Leaving the last rinse to dry in place (no water rinse) will retard regrowth.
Mildew preventative

 

[thinwater]

The other thing is that if dampness is the cause of mildew, you need to solve that. The first rule of keeping fresh bilge and lockers is keeping ALL of the water out plus good ventilation. It needs to be dry.

If we are talking engine spaces, diesel and black belt dust are other issues.

 

[Scott T-Bird]

The previous owner of my boat apparently had painted the underside of all the locker covers. It all was peeling very badly and it turned partially black. it took about 15 minutes per cover for me to wire brush , sand , acetone and paint the undersides . what was once very ugly and embarrassing is now pristine. If it lasts five years I will consider it a victory.

Depending on the paint, mold & mildew does grow in paint. That's why you can see it on painted surfaces inside homes - mold loves latex paint because there are organics in the paint that mold can feed on. I've seen where people paint their concrete basement walls only to find mold growing. It can't grow on the bare concrete but it does love some paints! In a boat, you may find some mildew on fiberglass surfaces, but I think that is because the spores are ever-present in the air and just lands there, but doesn't survive without organic "food". It's usually very easy to wipe off. The bare fiberglass surfaces are much rougher than gelcoat, so the stuff finds a way to get embedded. The belt dust in my engine bay was pernicious. I have a higher output alternator so I modified the pulleys for serpentine belts, which has eliminated the problem.

 

[rgranger]

I bought and old boat early last spring. It had been under a tarp for 6 years and was completely nasty. I tried a few different mildew cleaners and they all did some good but when I tried this one, it was like magic. I had a nice white hull again. It is sold at both Lowes and Home Depot.

Here is a link for Lowes

https://www.lowes.com/pd/30-SECONDS-1-Gallon-Mold-and-Mildew-Stain-Remover-Concentrated-Outdoor-Cleaner/5013150901?cm_mmc=shp-_-c-_-prd-_-lwn-_-ggl-_-LIA_HDW_127_Cleaning-_-5013150901-_-local-_-0-_-0&gad_source=1&gclid=CjwKCAjwkuqvBhAQEiwA65XxQK5xAl4PJWJw8skgwWVWhKqa43KrFK2k_MI8_3VJvlB3F7hpKesZDhoC_oEQAvD_BwE&gclsrc=aw.ds

 

[Ted10028]

I bought and old boat early last spring. It had been under a tarp for 6 years and was completely nasty. I tried a few different mildew cleaners and they all did some good but when I tried this one, it was like magic. I had a nice white hull again. It is sold at both Lowes and Home Depot.

View attachment 223608
you used that inside your boat?

Here is a link for Lowes

https://www.lowes.com/pd/30-SECONDS-1-Gallon-Mold-and-Mildew-Stain-Remover-Concentrated-Outdoor-Cleaner/5013150901?cm_mmc=shp-_-c-_-prd-_-lwn-_-ggl-_-LIA_HDW_127_Cleaning-_-5013150901-_-local-_-0-_-0&gad_source=1&gclid=CjwKCAjwkuqvBhAQEiwA65XxQK5xAl4PJWJw8skgwWVWhKqa43KrFK2k_MI8_3VJvlB3F7hpKesZDhoC_oEQAvD_BwE&gclsrc=aw.ds

 

[jssailem]

The label identified sodium-hypochlorite as a primary cleanser in the product.

Sodium hypochlorite is an alkaline inorganic chemical compound with the formula NaOCl(also written as NaClO). It is commonly known in a dilute aqueous solution as bleach or chlorine bleach.

Another popular cleaner is ammonia.

Mixing bleach and ammonia causes the release of toxic vapors called chloramines (these are a group of related compounds that are known to irritate the respiratory system). Exposure to these gases can trigger symptoms like watery eyes, nausea, coughing, shortness of breath, chest pain and irritation to the throat, nose, and eyes.

Be careful with your use of cleaning products.

 

[rgranger]

The label identified sodium-hypochlorite as a primary cleanser in the product.

Sodium hypochlorite is an alkaline inorganic chemical compound with the formula NaOCl(also written as NaClO). It is commonly known in a dilute aqueous solution as bleach or chlorine bleach.

Another popular cleaner is ammonia.

Mixing bleach and ammonia causes the release of toxic vapors called chloramines (these are a group of related compounds that are known to irritate the respiratory system). Exposure to these gases can trigger symptoms like watery eyes, nausea, coughing, shortness of breath, chest pain and irritation to the throat, nose, and eyes.

Be careful with you use of cleaning products.

Yes it is essentially bleach and a surfactant. I've tried dilute bleach alone and it did not work as well. I am working on the assumption that the surfactant is critical in the observed results.

Maybe some dilute bleach and a drop of Dawn dish soap would make a nice homemade alternative

 

[jssailem]

I am working on the assumption that the surfactant is critical in the observed results.

The label did reference a “Trade Secret” substance.

 

[DRhoads]

Another popular cleaner is ammonia.

Mixing bleach and ammonia causes the release of toxic vapors called chloramines (these are a group of related compounds that are known to irritate the respiratory system). Exposure to these gases can trigger symptoms like watery eyes, nausea, coughing, shortness of breath, chest pain and irritation to the throat, nose, and eyes

Isn't this also called mustard gas used in WW I?

 

[rgranger]

Isn't this also called mustard gas used in WW I?

No.... this is mustard gas

The reaction between bleach and ammonia release chlorine gas.... nasty stuff but not the same as mustard gas.

 

[rgranger]

No.... this is mustard gas

View attachment 223654

The reaction between bleach and ammonia release chlorine gas.... nasty stuff but not the same as mustard gas.

In your defense, there is a lot of missinformation on the internet about mustard gas. You can easily find a website that claims mustard gas is produced with bleach and ammonia... another page that claims it is made with bleach and battery acid (sulfuric acid) and another that claims that you make phosgine gas with bleach and ammonia.... that page also claims that phosgine is the same thing as mustard gas (also not true).

But all of those reactions produce toxic stuff so don't do it.... unless you are trying to kill a colony of roaches in a shed or something.... and then don't breath until you are well out of harms way. And don't let anything splash in your eyes or on your skin or cloths......