Make it shine.

[Donald Tyson]

Bob you are so right. There was a time when I lived by MSDS sheets.
The big difference btwn the Starbrite Instant Hull Cleaner and Toilet Bowl Cleaner is the type of acid. Starbrite's form of acid, Cyanic and another which I forget, is less reactive than the toilet bowl cleaner, which is hydrochloric acid. From what I've read Hydrochloric acid has a mild tendency to etch gelcoat. Over a long time using the toilet bowl cleaner there might or might not be a visible difference and I'm not willing to take the chance. When using the Starbrite product there is that old familiar smell of the Sanitizer (powdered sulfuric acid) we used on the farm to wash the milkers and soak the vacuum hoses.

Anyway, Whichever you folks choose to use I am reporting that the Starbrite Instant Hull Cleaner worked as it said, quickly as well. It took about 1/4-1/3 of the bottle to wipe it on and hose it off from the bottom of the green strip on down to the bottom paint. And I've seen no damage to the bottom paint in areas that I was careless with the application.

I recommend this product. There is no need to amend the recomendations for use as the product works as intended.

I use Starbright washing wax. it work but does not last. I too don't care for the polymers. I prefer Carnauba wax.

Thanks for the comments and videos everyone.

[thataway]

The "industry standard" wax is Colinate paste Fleetwax 885. There are a number of major players, and some auto waxes--none compare to good dedicated marine products.

Some like to use one system: 3M, Smooth, Chemical Guys, Nautical one, Strake, Starbrite, and a few others. I have tried most all. My personal belief is that Colinate Paste wax lasts the longest of the prure wax products.

[Tom Hruby]

I have had good luck with the Star Brite deck cleaner which does not have oxalic acid in it. I also use a melamine scrubbing sponge that gets rid of stuff without impacting the gel coat (as far as I can see).

Here is Google AI's response to the question of "effect on oxalic acid on gel coat."

Oxalic acid generally does not harm gelcoat when used correctly as a cleaner for stains like rust, but it can cause damage to other materials like metals or unsealed trailers. For the best results and to avoid potential etching, use a dilute solution, apply it for the shortest necessary time, and rinse thoroughly after use, especially on non-white gelcoats where it could cause bleaching.

How Oxalic Acid Works on Gelcoat
Removes stains:
.
Oxalic acid's primary function is to chemically convert rust (iron oxide) into a water-soluble compound called iron oxalate, which can then be easily rinsed away.
Cleans other stains:
.
It can also lift other stubborn stains, such as tannin and fungi, from gelcoat surfaces.
Potential Risks and Precautions
Leaching from metal:
Prolonged exposure to oxalic acid can cause metals to leach metal ions into the solution.
Bleaching:
While generally safe on white gelcoats, oxalic acid can cause bleaching on colored gelcoats, so always test in an inconspicuous area first.
Dilution is key:
Always use a dilute solution.
Rinse thoroughly:
After cleaning, rinse the area with plenty of water to remove the acid and the dissolved stain.
Protect surrounding materials:
If cleaning your boat on a trailer, wet the trailer down and rinse it thoroughly to prevent the acid from landing on it and causing potential damage.
When to Use and What to Do
Use for rust and grime:
Use a dilute oxalic acid-based cleaner to remove rust stains, dirt, algae, and grime from your hull.
Test first:
Perform a small, inconspicuous test on colored gelcoats to check for any unwanted bleaching.
Rinse and re-wax:
After cleaning, rinse the area thoroughly and consider applying a coat of wax to protect the gelcoat.
Consider alternatives for color:
For colored hulls, a fine polishing compound followed by wax may be a gentler alternative to remove oxidation and minor stains.

[ssobol]

[Donald Tyson]

Thanks Tom.
Very supportive article and as far as the dilution? I leave that to Starbrite. Furthermore. I will try the deck cleaner as well.

Ssobol,
I see your concern about micro plastics. But should I worry about micro Tee-Shirts for that is what I use....a folded tee holding lightly applied cleaner. No Scrubbing. Wash off in two minutes. Worked wonderful.

[Tom Hruby]

This discussion of how best to clean gunk off the gel coat on a boat has brought up some interesting questions about different cleaners and scrubbers. The basic conclusion is that pretty much anything that will do a good job of cleaning will also affect the gel coat. Your best bet is to apply a good coat of wax that becomes the layer that traps the gunk before it reaches the gel coat. You then wash off the wax with the gunk and re-wax. If more is needed I suggest a neutral cleaner and baking soda.

As a science nerd with a degree in chemistry, here is what I found:
1. As mentioned previously, oxalic acid will remove rust stains but will degrade gel coat.
2. Bleach will de-color organic compounds such as algal scum but alters the surface chemistry of gel coat.
3. Another "bleaching" compound is peroxide but it also has an impact on the surface chemistry of gel coat.
4. Vinegar is often suggested as a cleaner with a lower impact than bleach or peroxide, but being an acid needs to be removed quickly before it has a chance to react with the gel coat.
5. I have tried using a melamine sponge with success but is the abrasive hard enough to affect the gel coat? The answer to that is maybe. The hardness of melamine is measured on the mohs scale for minerals and is 4. A mineral with a higher mohs # will scratch one with a lower number. Unfortunately, the hardness of gel coats is measured on the Barcol scale (a deformation test) for plastics (~50) and is not easily transferable to the mohs scale. The only comparison I could find is that the scratch resistance of gel coat falls between that of a finger nail (2.5 mohs) and glass (5.5 mohs). (A fingernail will not scratch gel coat, but glass will.) Abrasives with a low Mohs scale rating include baking soda (2.5) and walnut shells (3.5). These might work better for cleaning gel coat.
6. Rubbing and polishing compounds have abrasives with very high mohs (aluminun oxide, silicone carbide, or silica). These should be used only if you want to remove the outer layer of the gel coat.

I think I will start using the Star Brite deck cleaner with baking soda as an abrasive.

[thataway]

You would be very hard pressed to measure the damage to gelcoat caused by using oxylic acid or bleach. Perhaps a bit more from toilet bowl cleaner. A friend used muriatic acid on my Tom Cat to remove some type of stain, and it permantly damaged the color of the dark green strite on the topsides.

Keep the hull well waxed and it should serve you well. Remove any Tanin stain before rewaxing. Old T shirts and microfiber cloths are generally safe for applying and hand polishing surfaces on our C Dorys.

You will not do significant damage to any SS fitting. Best if all SS is 316 alloy rather than other alloys.