Hull cleaner

zoidberg

zoidberg

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I'm preparing to clean the 'grubby white' grp hull-sides of a 40 y.o. boat and was considering using oxalic acid solution with wallpaper paste.... ahead of priming for painting.
After reading a couple of related threads, I'm not so sure that is most appropriate.

What does the hive-mind suggest is better?
 
A super guy called Neil ( they also have other names) who can for a fee get the best out of what you have. However if you are going to paint just abrade it as you need to remove the surface dirt and the decaying layer of gel coat. No doubt lots of fine filler and fairing as well if you want a really good final finish.
 
I’m a big fan of the Bilt Hamber stuff. Their surfactant “Surfex HD” is very good for both being biodegradable & non harmful to fishes, but also really good at cutting through grease / wax / road grime (on the car) and all sorts. I use it extensively. Worth it as a first pass to get off the grime before going over again with the oxalic acid to bleach back to white.

You might be able to combine the two in the one bottle to apply together; but I’m not a chemist so can’t guarantee it won’t create a noxious gas or some other risk.
 
Oxalic acid is not a cleaner other than it will remove iron based stains. Without seeing it but remembering your earlier post on the same subject then a mild abrasive and elbow grease then a polish with more elbow grease, a polishing mop will reduce the amount of elbow grease that you need but since elbow grease is cheap it's not obligatory.

As Tranona says and he is rarely wrong if you are going to paint it then just a fine abrading of the gelcoat in preparation for the paint is what you need.
 
One would hope that any stains would not creep through the primer and paint, but since this can sometimes happen I would use a detergent cleaner first. I don’t know if they differ much but such as International and Starbrite seem much the same to me. If there are any yellow or rust stains after that, then I would use oxalic acid, and enough abrasion to key the primer.
 
From reading the responses and the knowledge the yacht is 40 years old, now with some remarkable modifications, I might suggest that what you really need is a couple of impecunious students, on refection maybe more than a couple< on contract to conduct the work. Maybe advertise the opportunity as a means for the students to save on a gym subscription.

Or soda blast, fill, fair, paint - adding oxalic acid, degreasers, detergents (add to the list with bleach) etc to introduce some variation.

Take some before, during and after pictures.

I'm no longer a student, but might be considered by some (especially my wife) as being impecunious - and I'm not tempted.

But round here, Sydney's outskirts (and Noakes boatyard), students and a firm lash are the answer.

In view of the work on which you have embarked - beauty is in the eye of the beholder, though 40 year old yachts can have appeal. But based on your apparent focus - beauty is irrelevant - a smooth, clean, impervious hull will reward you with shorter passage times.

Jonathan
 
I'm long past the age when I could attract 'a couple of impecunious students' - although that stirs a faint memory! :)
I have previously soda blasted the lower hull and keel down to the gel - and that was a saga in itself! The ould boat seemed to heave a sigh when the weight of decades' worth of decayed paint came off. That led to a tie-coat of Jotun's finest Vinyguard88, and soon some of Jotun's best antifoul paint.

Some perspective from a better yacht racer than myself: "If it's below the waterline it can't be seen, and if it's above the waterline it doesn't matter..."

So now I'm looking to the 'tarting-up' phase.... with perhaps some Go Faster stripes.... :ROFLMAO:
 
Me ? I hit with Oxalic + Wallpaper paste ..............

Then its with general spray cleaner such as Cilit Bang or similar ....

Good hard pressure wash rinse off and let dry. Stand back and see what you get ... does it need painting or not ? Maybe just some flashes and stripes to liven it up ? Car accessory shops for trim tapes etc - applied using diluted washing up liquid to allow you to get straight etc ... squeezed hard once in place to push out the fluid.
 
Once you paint the topsides you're making a rod for your own back.

All I used to do with my 57-years old boat was to get the yellow stains out with oxalic acid, clean any stubborn marks with Cif, then finish with an automotive wash and wax. It didn't take long, and although wasn't up to concourse d'elegance standard it looked OK, and French passers-by used to say she was a jolie Bateau.
 
zoidberg said:
I'm preparing to clean the 'grubby white' grp hull-sides of a 40 y.o. boat and was considering using oxalic acid solution with wallpaper paste.... ahead of priming for painting.
After reading a couple of related threads, I'm not so sure that is most appropriate.

What does the hive-mind suggest is better?
Click to expand...
Someone else.
 
Poignard said:
Once you paint the topsides you're making a rod for your own back.

All I used to do with my 57-years old boat was to get the yellow stains out with oxalic acid, clean any stubborn marks with Cif, then finish with an automotive wash and wax. It didn't take long, and although wasn't up to concourse d'elegance standard it looked OK, and French passers-by used to say she was a jolie Bateau.
Click to expand...

Correct - once you go down the paint route - its a road to forever touching up / repainting ...

I could murder whoever painted my 38 red !!
 
Refueler said:
Fine ... but cost comparison of a bottle of SB vs a bag of Oxalic ?? I just bought 2 kilo of Oxalic at about 11 euros ... enough for whole yard of boats !!
Click to expand...
But you are not in the UK where purchasing a bag of Oxalic acid is quite difficult.
 
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