What's a good fiberglass hull cleaner/wax remover product?

Roj115

Petty Officer 2nd Class
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Aug 21, 2004
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102
I just took possession of a 2010 Glastron GT 180 BR that I bought second hand. The hull is white but has a hard thin yellowish film over much of the area below the waterline. I don't think it's algae or water scum residue because it's pretty yellow and consistent in color and fairly hard to get off. I tried taking a pressure washer to it and it does come off with pressure washing but slowly and you have to hold the wand only a few inches from the hull surface and make a few passes over an area to get it to come off. I figure at the prices car washes charge for pressure washing time, it will cost me $50 - $100 dollars to get the hull looking all white and new.

I suspect that the film is residue from some sort of wax that was used on the hull. I'm not sure what wax though, as I waxed my old boat every year for 40 years and it has never had a film like that on it.

Can anyone recommend a cleaning product that would make short work of that film/residue and leave the hull looking white and shiny again? I see Spray Nine makes a hull cleaner that seems like it might work okay for this purpose. Is that a good product for this or is there something better out there?

Oh yeah, the boat came from a lake somewhere in southern Minnesota, if that makes a difference.

Thanks!
 
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kcassells

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I would probably start with a pressure washer and some elbow grease. Then see whats left to contend with.
 

Roj115

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Aug 21, 2004
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102
This is the residue I'm faced with. It's pretty hard to get off. I'm thinking acetone might be what's required. I'd rather use something that's less toxic but I don't want to be spending 10 hours laboriously scrubbing this stuff off so something strong is required.

20150503_1217141_zpsme8beidq.jpg

20150503_1217211_zpsult6xnat.jpg
 

kcassells

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Someone should chirp in with some Green Ideas. There are a lot of products out there to break that down.
 

Roj115

Petty Officer 2nd Class
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Aug 21, 2004
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102
I'm actually starting to think that it is some sort of algae or lake mung. It's on the leg of the engine and the propeller too. Really hard to get off. Hard to scratch it with your fingernail, doesn't come off scrubbing with a nylon scrub pad. Undiluted Simple Green didn't seem to do much and neither did a undiluted citrus cleaner. Neither did brake cleaner.

Think I need something with some sort of organic enzyme in it.

What the hell kinda indestructible killer lake mung they got growin' in Minnesota?
 
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Highlife

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Jul 24, 2011
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Try a product called Zing or On/Off. I bought my On/off cleaner at Scheels Sporting Goods. Follow directions and it works great.
 

Roj115

Petty Officer 2nd Class
Joined
Aug 21, 2004
Messages
102
Try a product called Zing or On/Off. I bought my On/off cleaner at Scheels Sporting Goods. Follow directions and it works great.

I see both of those products are acids. Zing is HCL and On/Off is basically HCL and Oxalic Acid.

Another similar product would be Star Brite Instant Hull Cleaner and Spray Nine Boat Bottom Cleaner. They all use some form of acid so should act similarly. I'm thinking I'll maybe go up to the local building material store and pick up some Wood Bleach which is just powdered Oxalic Acid.

I'll post pics when I get the boat cleaned up.
 

NathanY

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Mar 16, 2002
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2,408
I use scrubbing bubbles stuff I use in my bathroom. Both of my boats get that stuff.
 

Woodonglass

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Dec 29, 2009
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25,924
Based on what I'm seeing, I'd recommend Hot, sudsy water and 180 grit wet/dry sand paper. I'm betting it'll come right off. Finish up with some 500 -1000 grit and then polish with a power polisher and the gel coat will shine like new. Don't get carried away with the 180 grit. Just enuf to get the gunk off and down to the white. Then use the 500 grit on ALL of the White and work up to 1000 grit. Then do the polishing. That's how this Old Dumb Okie would give it a Go!!!;)
 

DeepBlue2010

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Aug 19, 2010
Messages
1,304
What you are dealing with is fiberglass stains. All you need to do is to get yourself some Oxalic acid - sold as white powder - and mix it with hot water 4oz of Oxalic acid to a quart of hot water. Mix yourself a gallon and put it in a garden sprayer and spray the boat, all of these stains will disappear before your eyes. Rinse with water after and you are done. Oxalic acid ordered from the internet is cheap, can't remember how much I paid for the box right now but it was cheap even with shipping. If you buy it from a marine store, they will charge you a premium for it.
 
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