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Author Topic:   Gelcoat stains on hull
ivansfo posted 06-10-2003 04:22 PM ET (US)   Profile for ivansfo   Send Email to ivansfo  
I have a 1 year old 23 Conquest which is starting to show some yellow stains on the bottom of the hull. The boat gets rinsed down after every trip and is stored on a trailer when not in use.

I have been cleaning the stains off using 3M's Gelcoat cleaner/wax but it's a lot of work just to get a little of it off. It could take all day and lots of elbow grease to do the whole bottom.

Anyone know why I'm getting these stains? And is there an easier way to remove them?



jaccoserv posted 06-10-2003 08:16 PM ET (US)     Profile for jaccoserv  Send Email to jaccoserv     
The best product to get rid of that stain is MaryKate On & Off Hull Cleaner. Get a pestacide sprayer from your hardware store and spray on a small amount, 10 seconds later, the stain will drip away.... Just don't get it on your skin...OUCH!!!!
lhg posted 06-10-2003 08:17 PM ET (US)     Profile for lhg    
You need Starbrite's Instant Hull Cleaner. You should probably buy it in a gallon size, and pour it into a spray bottle, with adjustable nozzle. It instantly cuts the "yellow", but needs to be rinsed off with plenty of water before it dries. It also removes any wax job from the hull. You can either spray it directly on the hull, especially down by the keel if needed, or spray it into a wet rag and wipe on. It will "eat" the galvanizing off a trailer, so be careful when using it when boat is on a trailer. Keep the hose ready to rinse as needed, quickly.

If you can avoid it, never let the yellow stain go too long, as it can be increasingly hard to remove, and may require a powdered HD oxalic acid based hull cleaner like Sudburys or Bar Keeper's Friend. I always clean mine as soon as it comes out of the water, while the hull is still wet. "LimeAway" bathroom cleaner will also cut the yellow if you can't readily find the Starbrite's. MaryKate's makes a similar product.

bsmotril posted 06-11-2003 09:17 AM ET (US)     Profile for bsmotril  Send Email to bsmotril     
If you have a Galvanized trailer, try to keep either of these products off the trailer. They will quickly oxidize the zinc in the galvanizing. Flush the trailer well with water before and after application if the boat is on the trailer.
ivansfo posted 06-11-2003 01:23 PM ET (US)     Profile for ivansfo  Send Email to ivansfo     
Thank you all for the replies. I looked in my West Marine catalog last night and now understand why there's a need for a hull cleaner. I'll give the productions mentioned a try. My boat does sit on a galvanized trailer so I'll make sure to rinse it off good when done.


kingfish posted 06-11-2003 02:00 PM ET (US)     Profile for kingfish  Send Email to kingfish     

I have used both Starbrite's Hull Cleaner and MaryKate On & Off, and I can tell you from experience that On & Off is *much* more potent than Starbrite Hull Cleaner. I generally feel that the less aggressive the material that will do a particular job like this is the right one for you, and so I second lhg's advice. Try that first, and flush your trailer before, during and after. If you go straight to On & Off, water alone will not do the trick (I know; I've been there); cover the exposed galvanized with visqueen *and* flush it afterwards.


lhg posted 06-11-2003 03:52 PM ET (US)     Profile for lhg    
I have used the Starbrite product for 15 years now with great success, but never the MaryKate product. If it is strong as Kingfish indicates, I would not use it. I had assumed it was the same as Starbrite's, which was not correct.

I recently saw the Starbrite product in Walmart, boating section.

Hugh Williams posted 06-11-2003 04:26 PM ET (US)     Profile for Hugh Williams  Send Email to Hugh Williams     
If you were to use 3M wax to get it off, I would the restorer/wax instead of the cleaner/wax. It has a rubbing compound in it. I used it after using the hull cleaner and the spots I missed with the cleaner, the wax took it off with good rubbing. Works well on stainless steel railings. . An electric buffer would work well with this product on the hull. I also used it to clean a brass lamp too. lots of work
kingfish posted 06-11-2003 05:31 PM ET (US)     Profile for kingfish  Send Email to kingfish     

On & Off has phosphoric, oxalic *and* hydrochloric acid in it - no kidding! It "smokes" when you take the top off, but you can't believe how it removes stains (and barnacles and plant growth, I understand).

Our well water has a lot of iron and/or other stuff that causes rust or rust-like stains, and I keep a bottle of On & Off around to soak shower heads and faucets heads in every few months to clean up the screens and deposits. Takes about 2 minutes, rinse them off, and they're like new!

ivansfo posted 06-11-2003 05:48 PM ET (US)     Profile for ivansfo  Send Email to ivansfo     
I was just at Wallyworlds during my lunch break and found they sell Starbrite Hull Cleaner and also Bar Keeper's Friend. I ended up picking up a bottle of the hull cleaner since the BKF looks like a bottle of Comet (too abrasive?)



lhg posted 06-11-2003 06:29 PM ET (US)     Profile for lhg    
I'm not sure if Bar Keepers Friend is just powered oxalic acid, or whether it has an abrasive in it besides. If it does, don't use it.
Jarhead posted 06-11-2003 06:55 PM ET (US)     Profile for Jarhead  Send Email to Jarhead     
I have a can of Bar Keeper Friend in front of me now and it does list a "mind abrasive".

I've used it and can recommend it highly. Removed oak stains easily and left the boat showroom bright.

My 2 cents.

buzzoff posted 06-11-2003 07:24 PM ET (US)     Profile for buzzoff    
I use Ajax, foaming cleanser.
kingfish posted 06-11-2003 07:52 PM ET (US)     Profile for kingfish  Send Email to kingfish     
bum ba ba bum bum
fjjpal posted 06-13-2003 12:47 AM ET (US)     Profile for fjjpal  Send Email to fjjpal     
Is there any way to repair the damage that ON\OFF cleaner does to your trailer? Can you sand the spots and spray with anything that resembles the original galvinized finish. I did a number on mine before I realized what it was doing.
kingfish posted 06-13-2003 08:21 AM ET (US)     Profile for kingfish  Send Email to kingfish     
I may be wrong, but here's where I have come down on this with my trailer, with which I learned the hard way like fjjpal:

1. I don't believe that, short of re-galvanizing your trailer, there's any way to bring the galvanize back to a shiny new condition. Paint, like cold-gal etc., is a second best program insofar as protection and appearance are concerned when compared to real galvanize, in all conditions. I believe trying a galvanize paint will create an even worse looking condition.
2. I think all that has happened is that the surface of the galvanize has been oxidized a whole lot faster than it would be under normal operating conditions. It might be microscopically thinner, but it is not out for the count. I simply keep mine clean, and the "whiteness" pretty much disappeared within a short while, and the trailer was left looking a little "mottled", which condition continues to fade also.


lhg posted 06-13-2003 03:12 PM ET (US)     Profile for lhg    
I have found that one of the difficult galvanized areas to keep looking good are the galvanized wheel rims. They go pretty quickly and get dark looking, and grease/grime gets increasingly hard to remove and clean. I found that spray painting them with RustOleum silver paint really sharpens up the wheels, keeps them easy to clean, and they still won't rust.

I also saw an older Continental galvanized trailer in FL that had been silver spray painted. Looked brand new. sells a product they claim renews and brightens galvanized finishes. I am going to try it one of these days.

kingfish posted 06-13-2003 04:18 PM ET (US)     Profile for kingfish  Send Email to kingfish     
I may try to pick up some of that paint from Champion - it would be great to find out there *is* a good way to spruce old galvanized up-
nolester posted 12-08-2003 07:09 AM ET (US)     Profile for nolester  Send Email to nolester     
Just a vote for Starbrite Hull Cleaner here! I just removed, with very little effort compared to the elbow grease method, some below-water-line yellowing by spraying and waiting with this stuff. It has oxalic acid, too, but not the other acids I guess the on and off has.

So, maybe I didn't get fishing this week; but, when I go next I will be in a clean white hull.

I also used this brand of deck cleaner, one made for non-slip [i.e., rough] surfaces, scrubbing with a deck brush with a long handle that I got at Home Depo. It worked a lot better than boat soap, even getting up the ol' mullet blood from my bait cutting on the bench seats.

joncoastie posted 12-08-2003 10:31 AM ET (US)     Profile for joncoastie  Send Email to joncoastie     
My boat is constantly gettign stained, as I keep her in a high/dry on a brackish river off the Gulf. I have found that MaryKate's On/Off is a very good product but much more expensive than "Rustaid", which is available at Walmart and HomeD. I apply it with a pair of good rubber gloves and a sponge. One gallon usually gets me atleast three applications. I have not used it on my Whaler yet but used to use SnoBowl on my sailboat to bring the white back out and then waxed her with Collinite Fleetwax paste. One last thing, I just purchased small bottles of 3M finesse-it II and 3M rubbing compound at Walmart for a nearly 40% less than the sharks at West wanted for it. I understand making some profit but geeeze!

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