Today's discovery: GRP cleaner

JumbleDuck

JumbleDuck

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I used to get brown stains off my hull with "Easy Clean" fibreglass cleaner. A couple of years ago it went off the market, and until today I hadn't found an effective replacement. Y10 just didn't do it. Not tough enough.

Today the nice people in Largs Chandlers recommended and sold me some Owatrol Owayell Gelcoat and Metal Renovator, which I have discovered works like a dream. It has a gloopy consistency like Y10 - you paint it on, leave it for 5-10 minutes and then remove with lots of water. Brown stains just vanished and some nasty green stuff came off with gentle rubbing.

It's phosphoric acid based, and smells like Jenolite did before it went wimpy. I think Easy Clean was phosphoric as well.

This is probably old news to lots of you and won't interest the oxalic-acid-and-wallpaper-paste (the worst flavour Walker's ever tried) devotees, but I thought I'd pass the word on.

I got both sides of a 26 footer done from a single 1 litre bottle, with loads to spare.
 
oxalic acid in powder form on eBay, mix with wallpaper paste, does the job. Or if you grow rhubarb boil the green tops and when cool that works as well.
 
omega2 said:
oxalic acid in powder form on eBay, mix with wallpaper paste, does the job. Or if you grow rhubarb boil the green tops and when cool that works as well.
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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.
 
pauly78 said:
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.
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Be vary careful; when wallpaper paste dries it's not going to be easy to remove. It may (possibly?) be better to use gealtine to hold the oxalic crystals in suspension.
 
pauly78 said:
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.
Click to expand...

I just use it saturated and brush it on. As long as there is a little bit left undissolved in the bottom, that works for me. I gave up on wallpaper paste. It just dried on and was then difficult to get off.
 
omega2 said:
Or if you grow rhubarb boil the green tops and when cool that works as well.
Click to expand...

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....
 
LadyInBed said:
Why buy all these fancy products to get brown stains off GRP when a bottle of Harpic from the Pound Shop does a fantastic job?
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it must be Harpic limes scale remover or any other lime scale removing toilet cleaner , its thick and usually coloured apply with a dry cloth no need to rub or scrub just stand back and watch the magic that is Hydrochloric acid , works in the same way that Oxalic acid works. Wear gloves and protect your eyes. then rinse off with plenty of water, you can buy it almost anywhere from one pound to two pounds a bottle and I use less than one bottle to clean my 30 foot boat
 
kieronriley said:
it must be Harpic limes scale remover or any other lime scale removing toilet cleaner , its thick and usually coloured apply with a dry cloth no need to rub or scrub just stand back and watch the magic that is Hydrochloric acid ...
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Good luck.

Composite materials are exposed to a range of hostile environments with consequent degradation in terms of mechanical properties. However, the bibliography is not sufficient to establish a full knowledge about the effect of hostile environments on mechanical properties. This work intends to study the response to flexural and to low velocity impact of a glass fibre/epoxy composite after immersion in two different acid solutions, hydrochloric acid and sulphuric acid. These solutions affect significantly the flexural and impact strength, however, the hydrochloric acid was responsible for the worst results.

-- Effect of different acid solutions on... (PDF Download Available). Available from: https://www.researchgate.net/public...erent_acid_solutions_on_glassepoxy_composites [accessed May 08 2018].​
 
The safety sheet for the Owatrol product says that it is an acid base , and "Do not use on galvanised metal or raw aluminium."


Rhubarb. Leaves are great for making a natural insecticide when a small drop of detergent is added. Not for food crops though.
 
A good GRP cleaner is ''Silky cream cleaner''. It cleans off black streaks but not necessarily heavy duty stains. It is also very economical as a little goes a long way.

Bar keepers friend power cream is good at removing stains from GRP including rust stains - it is oxalic acid based. I apply it and leave it on to do its work. Similar I think to the wallpaper paste and oxalic crystals trick except when it dries it can be washed off easily.

I have used Harpic on a tough limescale at the waterline. But washed it off with plenty of water.
 
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