Rust on gelcoat

[Fons]

Hi,
I have rust on the gelcoat from rusted srews, I have removed all the srews and will replace with new ss srews. What is the best way to remove the rust stains inside the boat on the gelcoat.
Thanks for looking.
Fons

 

[Mark42]

Re: Rust on gelcoat

I've used CLR (Calcium, Lime, Rust) to remove rust stains on the gel coat, vinyl upholstery and other plastic surfaces. It can be applied straight with no worry about damaging the plastics. Depending on the severity of the stain, it comes completely off, or goes away to the point of being a shadow. There are other products that are even stronger you can try. CLR is a good one to start because its very safe on the boat.

If the stain remains as a shadow, then some rubbing compound followed by polising compound should remove the remaining stain.

It also works well to remove rust stains from stainless without heavy polishing.

 

[lmannyr]

Re: Rust on gelcoat

I tried compounding and CLR with no results. Any other ideas??

 

[Bob_VT]

Re: Rust on gelcoat

Wet sanding?

 

[lmannyr]

Re: Rust on gelcoat

Muriatic Acid did the job just right. Works GREAT on Stainless steal too. Makes sure you wear hand/eye protection and a mask.

 

[dorelse]

Re: Rust on gelcoat

I used 'Barkeepers Friend'. $1.99 at Home Depot. Mixed it into a paste and let it sit on the stain overnight. (Per the instructions on the can.)

Here's are the results:

 

[saildan]

Re: Rust on gelcoat

I tried compounding and CLR with no results. Any other ideas??

Did you clean away the wax left behind by the rubbing compound? That can create a barrier to water based stain removers. A wipe with a clean rag dampened with mineral spirits or acetone should do the trick.

I used 'Barkeepers Friend'. $1.99 at Home Depot. Mixed it into a paste and let it sit on the stain overnight. (Per the instructions on the can.)

Bar Keeper?s friend

contains Oxalic Acid, great for removing metallic stains and it won?t attack metal parts as severely as CLR (read their warning) if it accidentally comes in contact. Still, flush the area with plenty of cold water when you finish cleaning.

Oxalic acid (the stuff that makes rhubarb tangy) is also found in a product called Whink Rust Stain Remover

or ?wood bleach? found at the hardware store.

 

[lmannyr]

Re: Rust on gelcoat

Didn't think of removing the wax first. Good point. The muriatic acid doubled as a rust remover on the rest of the stainless too.

 

[saildan]

Re: Rust on gelcoat

The muriatic acid doubled as a rust remover on the rest of the stainless too.

No doubt - Muriatic (hydrochloric) acid has a veracious appetite for many things. Lucky it didn't continue on to pit the base metal too.

With rust stains, not simply salty polyps and a milky haze, something in that hardware assembly isn't actually stainless.

 

[jspano]

Re: Rust on gelcoat

have you ever heard of lesco or john deerelandscapes(bought lesco out)
they carry a product a product called rust-eraser. liq 1 gal mild acid will not hurt painted surfaces, can be used to clean bare alum, do not get it on glass.
i have used it alot, removes iron stains.

 

[chasecd]

Re: Rust on gelcoat

Folks,
I use Iron Out in my toilet water supply basin. I just pour some in the tank and the bowl and leave it. Works like a champ. Pour some in and leave overnight, flush out with the next use. Now, I have not used it on my boat yet, so I don't know of any adverse affects on the gel coat.

I have been advised to use Muriatic Acid to remove rust stains and the previous owner of my boat used Oxalic Acid once a year to whiten it. I have the Muriatic Acid, but have not used it yet, which is why I am on here, to read and learn the various methods and what works and what doesn't.

I just bought some 3M cleaner and wax, both for light and heavy oxidation, from WM. Tried it out last night and it seemed to work well to remove the mildew and leave a smooth coat. However, I didn't really notice difference between the light and heavy products.

I like the Barkeepers Friend idea though. Readilly available at Lowe's and Wikipedia states its ingredient is, guess what? None other than Oxalic Acid.
Cheers
chasecd

 

[GatorMike]

Re: Rust on gelcoat

I always just used Starbright rust stain remover, it is a bit pricey like most starbright products but is the easiest product I ever used. You just spray it on and come back 5 minutes later and the stain is gone. I have seen stuborn stains that I compounded, buffed, and used CLR on with no success. One spray of Starbright and they just went away in minutes.

An interesting side note, I am a building inspector. A while back I was talking to the project manager of a large apartment complex I was inspecting. He was complaining about how much money he was having to pay some tub restoration guy to get rust stains out of fiberglass jacuzzi tubs that workers had left nails or screws laying in. He said the guy charged him $75 per tub. I brought him a bottle of Starbright and told him to try it and if it worked he owed me $12 for the bottle. The next time I saw him he was grinning from ear to ear. He said I saved him a fortune. I felt kind of uneasy collecting my $12 though, it doesn't look good when a county inspector is being handed cash on a job.