Today's discovery: GRP cleaner

[Andrew41]

I find Largs marina chandlery staff to be extremely knowledgeable and helpful in most things marine.
Down in Ardrossan I was speaking to the boat valeter and he swears by Oxalic acid and he mixes up a solution in a spray bottle and uses it on everything from GRP hull brown staining to rustmarks, sprayhoods and teak deck marks. He said that surveyors have said that it is about the only cleaner you could use safely on the whole boat. Obviously one needs to mix the correct solution and do some testing first. I don't want to open up a debate but it was a coincidence that this came up yesterday as I was taking out a rust streak on my white GRP hull with 1,000 grit wet & dry as Farecla G3 with a machine wouldn't shift it and then his Oxalic shifted it while we stood and watched it and shot the breeze for a couple of hours 'till it got dark as he was waiting for some Coppercoat to cure and I went home having done very little as usual but had a nice time. Of course it's raining today.

 

[macd]

What kind of ratio do you mix this, how long is it left on and is the wallpaper paste easy to get off afterwards? My decks desperately need doing, I’ve got dark marks/stains all over.

Wallpaper paste is only really necessary to thicken the oxalic on steep surfaces, such as topsides. Washing-up liquid helps the oxalic wet-out and cling, and should be enough for cleaning decks. As suggested, mix in warm water with just a few undissolved crystals remaining. Leave for 15 minutes or so. Rinse very thoroughly afterwards.

 

[BelleSerene]

Tell me more about the rhubarb trick. Milady grows the stuff, lots of it, and most of the plant ends up in the compost bins. Your idea would seem to give the stuff some utility....

The active ingredient in most hull-cleaning fluids is oxalic acid. As someone observed, it's cheaper just to buy the crystals (*) and mix them with water.

The main poisonous ingredient in rhubarb leaves is oxalic acid. There's some, but less, in the stalks.

Absolutely no idea what the concentration of the stuff would be!... OK, so

Wikipedia [ https://en.wikipedia.org/wiki/Rhubarb#Chemistry ] says 'a typical value of oxalic acid in rhubarb leaves is 0.5%' (The context implies this is by weight)
A data sheet [ http://www.greendept.com/maximpulse/oxalic/Resources/star_brite_msds_409772.pdf ] for StarBrite's hard stuff, 'Instant Hull Cleaner', says the concentration is 5-10% (weight for weight) and that you should use the stuff neat. (I believe regular deck-cleaner products are less concentrated than that.)​

OK, chemistry was my 'B' grade. I am sure someone who understands it will be along to explain how to boil or trample on enough rhubarb leaves to create a deck-cleaning stew...

(*) BTW, if you're playing with the raw crystals, do wear impermeable gloves as it permeates the skin and does nasty stuff to you.

 

[TimfromMersea]

IMHO the German Yachticon ‘Anti Yellow’ (or on the German product Anti Gilb) is the most effective.

 

[Marine Reflections]

When will people realise that surface condition needs to be at a decent level to stop dirt gathering in the highs and lows?

All this heavy duty cleaner is not good..

Get the condition right and all that would be needed is water and a sponge..

 

[VicS]

The active ingredient in most hull-cleaning fluids is oxalic acid. As someone observed, it's cheaper just to buy the crystals (*) and mix them with water.

The main poisonous ingredient in rhubarb leaves is oxalic acid. There's some, but less, in the stalks.

Absolutely no idea what the concentration of the stuff would be!... OK, so

Wikipedia [ https://en.wikipedia.org/wiki/Rhubarb#Chemistry ] says 'a typical value of oxalic acid in rhubarb leaves is 0.5%' (The context implies this is by weight)
A data sheet [ http://www.greendept.com/maximpulse/oxalic/Resources/star_brite_msds_409772.pdf ] for StarBrite's hard stuff, 'Instant Hull Cleaner', says the concentration is 5-10% (weight for weight) and that you should use the stuff neat. (I believe regular deck-cleaner products are less concentrated than that.)​

OK, chemistry was my 'B' grade. I am sure someone who understands it will be along to explain how to boil or trample on enough rhubarb leaves to create a deck-cleaning stew...

(*) BTW, if you're playing with the raw crystals, do wear impermeable gloves as it permeates the skin and does nasty stuff to you.

https://www.rhubarb-central.com/

https://www.rhubarb-central.com/rhubarb-plant-facts.html

http://rhubarbinfo.com/

http://rhubarbinfo.com/poison

 

[JumbleDuck]

When will people realise that surface condition needs to be at a decent level to stop dirt gathering in the highs and lows?

All this heavy duty cleaner is not good..

Get the condition right and all that would be needed is water and a sponge..

Cobblers. Staining of the sort we're discussing is NOT the same as dirt collecting in low spots. Thanks for your help.

 

[Marine Reflections]

Cobblers. Staining of the sort we're discussing is NOT the same as dirt collecting in low spots. Thanks for your help.

I'll have to bow to your superior knowledge

 

[Marine Reflections]

Try thrashing it it with some rhubarb then.

 

[Marine Reflections]

Spirit of salts

Starbright's barnacle remover

Viakal

Oxalic Acid

Or you could try removing the highs and lows so it all has nowhere to park.

Or rhubarb lol

 

[LadyInBed]

Or you could try removing the highs and lows so it all has nowhere to park.

If it's down to an uneven surface, how do you explain the even distribution of the brown stain all along the hull?

 

[JumbleDuck]

If it's down to an uneven surface, how do you explain the even distribution of the brown stain all along the hull?

And why it's along the waterline and why it's associated with metal salts and ... oh, what's the use. I'm guessing from the username that he runs a boat polishing business.

 

[Poecheng]

I'm guessing from the username that he runs a boat polishing business.

Yes he does and, from the looks of things, is simply excellent. [Wrong coast for me and no connection whatsoever]
He is known to many on here because, when expertise in this area of boat maintenance is needed, Marine Reflections steps in and sets out how he, an expert with vast experience (my words not his description), does it. Not just a line or two normally but long, detailed posts generously giving away his expertise as to how to do it, what tools are the best and what products are the best.
Not content with that, last year he ran a long term test on the best polishes/sealants and posted up the results during the test for all to see and judge. These were long, detailed posts with photos and analysis - simply excellent.

So, yes he runs a boat polishing business.

If, by posing that question, it was a snide way of inviting cynicism of his post or his motivation for posting then that is simply unfair. It certainly wasn't intended to be a compliment for MR - it was intended to undermine him.

So, in Marine Reflections, we have a lifetime of expertise in an area that most of us are interested in and who is very generously willing to share it with us - down to the tiniest detail and at great length - and you disrespect him publicly in this and your earlier post #27 (effectively telling him he is an idiot and to butt out).

I only hope that Marine Reflections understands the rest of us appreciate his posts and that he continues to help us as before. If he doesn't and decides it is not worth the hassle, it will be your fault entirely and we all will be the losers. You have nothing to offer on this topic.

It is entirely fair to disagree with, or to question, others - no matter what their expertise - that is what the forum is all about. But you seem to find the need to go much further and to run people down. You seem to do it repeatedly. I think you should take a second look at your draft comments before posting them and take out personal parts of them. That will avoid the risk of contributors just walking away. And me posting like this.

 

[Marine Reflections]

Poecheng, thank you for those kind words.

Firstly though, an apology to the OP.
I believe it was my attitude and lack of explanation that invited the comments - quite deservedly.

It is of no justification, but I've just lost a friend and so shouldnt have posted at all. My posts were shall we say not up to par, they were too quick, without thought or delivery, sarcastic and I genuinely apologise.



My concern was triggered by an on-going consideration to the increase in harsh chemicals that are used in our industry.

Spirit of salts, Oxalic acid and various other acids are discussed as though they are dish soap. They are effective, but my aim here is to jolt thought into prevention rather than continue to coat with acids.

The highs and lows I talk about are I guess the reverse of when trying to provide a key so something will stick, say for example keying the hull in order for anti-fouling to bond.
The reverse has to be the case when trying to get things not to stick.

The highs and lows are at a microscopic level and would be the difference between dirt / scum / metals / oils etc attaching to the waterline or at least being easy to remove.
The more uniformed the surface (be it a waterline or anywhere else) the easier it is to remove.

This is at the cornerstone of my motivations to post on here, to get us all to consider the enviromental impact harsh cleaners have as opposed to getting the condition right so things don't stick and can be easily removed.

There are effective cleaners (as above and in my earlier posts) but these are to remove bonded..what is a smarter choice is to have a surface that doesn't require these methods.

The first step in this process is to start to look at the rejection or acceptance level of a surface.

We are becoming too quick to jump to a chemical that surely does the job in a fizz, but will hqve to be repeated over and over. Wouldn;t it be nice to have a surface that the contaminates didn't bond to in the first place?


Anyhow, many apologies for my earier comments and hope the OP can find it in himself to forgive me, I had the best intentions at heart.

Tony

 

[JumbleDuck]

Yes he does ...

Thanks. Just as I thought.

You have nothing to offer on this topic.

Have a look and see who started this thread with what he hoped other people would find a useful suggestion.

 

[JumbleDuck]

We are becoming too quick to jump to a chemical that surely does the job in a fizz, but will hqve to be repeated over and over. Wouldn;t it be nice to have a surface that the contaminates didn't bond to in the first place?

It's a good point, and I don't particularly like using strong acids unless I have to. However, I'm not as sanguine as you are about the curative powers of polishing. It definitely helps prevent some sort of dirt, but brown staining at the waterline seems to be a chemical process rather than a simple accumulation of dirt.

A couple of years ago I had my hull professionally polished. It certainly kept the upper portions cleaner and soot from the exhaust of the rather smokey engine I had wiped away very easily that year, but it didn't make any difference at all to the couple of inches above the waterline, which went just as brown as usual.

You'll be relieved to know, I hope, that I spent much longer waxing the cleaned hull afterwards than I did with the nasty stuff ...

 

[Poecheng]

Poecheng, thank you for those kind words.

A pleasure - you deserve it.
I am very sorry to hear of your news; your posts were a model of restraint and reflect well on you. :encouragement:

 

[Marine Reflections]

It's a good point, and I don't particularly like using strong acids unless I have to. However, I'm not as sanguine as you are about the curative powers of polishing. It helps prevent some sort of dirt, but brown staining at the waterline seems to be a chemical process rather than a simple accumulation of dirt.

A couple of years ago I had my hull professionally polished. It certainly kept the upper portions cleaner and soot from the exhaust of the rather smokey engine I had wiped away very easily that year, but it didn't make any difference at all to a couple of inches above the waterline, which went just as brown as usual.

You'll be relieved to know, I hope, that I spent much longer waxing the cleaned hull afterwards than I did with the nasty stuff ...

It is the lapping of water that wets just slightly above the waterline and then recedes and dries the total dissolved solids in the sun resulting in the scale that is the norm.

This sparks the debate between hydrophobic and hydrophilic in these areas, but that discussion (although related) is perhaps for another thread.

Yes, this is an area of exposure that pulls the principles we all know into the light.

If anywhere is going to reveal results of this concept, it is at the waterline.

Let's just say you have a waterline that is similar to that of a brand new tefal non-stick frying pan. Where water behaves as though it was mercury.

You'll agree that marks or contaminates won't stand much of a chance when it comes to bonding and can be easily removed with a sponge and more water.
This ideal isn't as difficult to achieve as one might think and only takes a little more effort.

It is in this area I would like to help.

 

[Hydrozoan]

I have pondered here before if at least some of the brown staining might be the result of the break-up of the floating colonies of Phaeocystis species, blooms of which are common in nutrient-enriched coastal waters and can produce large amounts of white foam which quickly turn brown. I’m not sure what implications that would have for its removal, but it’s interesting that the Phaeocystis exudate itself obviously contains a strong surfactant, and would probably concentrate at the sea surface microlayer.

(I’m not sure where Jumbleduck’s reference to ‘associated with metal salts’ at #32 came from, but ISTR that elevated zinc levels in the seawater were encountered on the break-up of Phaeocystis blooms and it would not surprise me if the exudate complexed metal ions.)

Of course there are many other potential sources (oil, humic substances etc.) of brown waterline staining ... but when I see images like the topmost here, I cannot help wondering if it may have a bigger role than may be realized. http://www.seos-project.eu/modules/oceancolour/oceancolour-c03-p05.html

 

[JumbleDuck]

It is the lapping of water that wets just slightly above the waterline and then recedes and dries the total dissolved solids in the sun resulting in the scale that is the norm.

Perhaps I am not recognizing it, but on my boat I haven't seen anything I'd describe as scale - in the sense that the stained area feels smooth.

It is in this area I would like to help.

She's not launched yet, so if you would like to suggest something I could do to the waterline to reduce the problem, beyond the current layer of wax - I'll happily do a test section and see how it compares at the end of the year. No silicone! Better still, perhaps PBO would be interested in doing a test?

(I’m not sure where Jumbleduck’s reference to ‘associated with metal salts’ at #32 came from ...

My assumption was that almost all colour comes from metal salts of some sort, and that this is a phenomenon of local penetration of the GRP, as you see with rust stains on deck.