Bleach on GRP?

[FlyingDutchman]

Having spent the easter days cleaning and polishing the boat, we found a few yellowish stains that we coulkd not remove with a normal cleaner.
As the boat is white, I thought of using bleach. Are there any adverse effects from bleach on GRP?
Thanks all!

 

[aidancoughlan]

My surveyor advised using bleach to clean out little fine scratches when I bought my boat. I havnt had the courage to do it yet, or research what types of bleach to use. So, I'll be interested in the responses too...

 

[bugs]

Oxalic Acid will normally remove the yellow stain. This is the main ingredient in Y-10 (available in chandlery). It must also be used in Limescale remover for your loo (available everywhere!) which I have had success with. I read (no doubt somewhere here) that putting wall paper paste into it will make it gel for vertical surfaces. It is amazing to see the quick and effortless way the stain is removed. I used it on the deck too which while not yellow was dull looking- it came up like new.

I have one stain that is not coming off with Y10/limescale remover. It was suggested here that I use T-cut for this section then polish it.

I dont know if bleach will work, perhaps they meant the limescale remover type.

 

[boatmike]

Buy some Oxalic Acid from your local chemist. Use it fairly diluted at first and increase strength till it gives required effect. Wear gloves though it's not kind to skin!

 

[cass123]

An old guy at our jachthaven swears by fresh lemon (citroen) juice
rubbed in , left for half an hour then rinsed clean.
Have never tried it as our boat is steel hulled but have heard others talking about it.

 

[bruce]

on my '74 glass boat i use a spray bottle with laundry bleach undiluted, mist on and let set for about a minute, hose off...instant whiter than white. easiest to wash hull/deck first and mist after washing soap off.

 

[FlyingDutchman]

Thanks everybody!
I will give the different remedies a try next weekend and report back on the results.
Cheers!

 

[oldsaltoz]

Bleach and Fibreglass do not mix.......

You can do this test yourself if you have any doubts.

The CSIRO test all waterproofing membranes for suitability to become listed in the Australian Standards.

I was amazed to see one of the simple tests they carry out prior to spending big bucks on a full test.

Take two jam jars, place a sample of the membrane in each, fill one with 50/50 mix if bleach and water; fill the other with a 50/50 minx of Domestos and water.

Stand on a window sill for 14 days.

Fibreglass comes out very soft, even floppy.

The moral of the story is that bleach will clean fibreglass, but, you need to sure it's not draining into cracks or holes that can not be rinsed clean.......

Avagoodweekend.