Bleach & Fibreglass test results.

oldsaltoz

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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 be listed in the Australian Standards.

I was amazed to find one of the simple tests they carry out prior to spending heaps on a full test.

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

Looking forward to some interesting resposes on this one.

Avagoodweekend.
 

boatmike

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Re: Bleach & Fibreglass test results.

Actually it does not make any difference if there are hair cracks. As I said in my original post The resins used to bond FRP are degraded by bleach. It may not melt your boat immediately but it DOES have an effect. Over time it will etch into the surface, cracks or not. Other types of polymer plastic are similarly affected too. Thats why you should not put bleach down a marine toilet
 

aidancoughlan

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This is an interesting piece of information, particularly as it comes from OldSalt . As i had mentioned on a previous post I was advised by my surveyor to use bleach to 'clean' hairline cracks in my gelcoat. I havnt' done it yet (it seemed something to check out first). Glad I've waited...
 

Thistle

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Re: Bleach & Fibreglass test results.

No: oxalic acid does not contain bleach. It is exactly what it says on the tin - oxalic acid!!!
 

oldsaltoz

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G'day Ray,

<<Do you mean that both samples are similarly affected?>>

Yes, both samples are effected, the hospital strength Domestos works very well.

For what it's worth, coating the samples with an epoxy resin all but prevents any damage, but leave the sample in there for a few months and will suffer.


Avagoodweekend.................
 
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Surely Domestos is bleach anyway. Sodium hypochlorite? Are you immering chopped strand mat or woven rovings or is it a panel of GRP? If one of the former aren't you just experiencing a "Wetting" effect?

Steve Cronin
 

oldsaltoz

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G'day Steve,

It's a strip of cured standard resin with 256 gram chopped strand mat in this case, but I'm advised the same applies to rovings.

Top coats (chemical barriers) can be applied, but only to one side in the first test.

Hoope this helps.
 

boatmike

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Re: Bleach &amp;amp;amp; Fibreglass test results.

I didnt say it did! The question was would DOMESTOS AND BLEACH have the same effect. Of course Oxalic Acid does not contain bleach. In fact if you mixed the two it would cause a fairly violent reaction.
 

Vara

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Re: Bleach &amp;amp;amp; Fibreglass test results.

My understanding is that domestos is bleach with a bit of stuff to make it a bit sticky and improve its wetting properties(surfactant),according to Lever web site,it is a Hypochlorite bleach(sodium).
I would expect in the pure bleach v Domestos test,for the end result to be the same but that the Domestos would act more quickly as a result of it's better wetting properties.
 

BrendanS

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Re: Bleach &amp;amp; Fibreglass test results.

No, Oxalic acid is exactly that. It's an acid. It contains no bleach in the accepted sense. It does have bleaching qualities in that it can remove stains, but it does it by a different process to household bleach.
 

Thistle

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Re: Bleach &amp;amp;amp;amp; Fibreglass test results.

Sorry! Misunderstanding here from me (even after re-reading the posts just now) and, I think, Silverseal. I quite agree about the violent reaction - definitely one in the "do not try this at home" category!
 
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