Daihatsu Skywing - Electrolytic corrosion of pipe in hose

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Sun 17 May 2020 15:27
Daihatsu Skywing - Electrolytic corrosion of pipe in hose - edlithgow

Quite bad, with pin holes. The other end of this steel pipe was leaking at a gasket and / or O-ring, which is why I took it off. Made a polythene gasket from lay-flat irrigation hose and supplemented the O-ring with RTV silicone. No corrosion that end.

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Lucky leak really, because this end probably wouldn't have lasted much longer.

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I put some sealant goop on, then PTFE tape, and finally polythene sheet, to give electrical separation of the steel from the rubber. Put a coil of beer can aluminium (also gooped up) inside for physical reinforcement and cathodic protection, though there is some risk of blockage.

Is corrosion of steel pipes by rubber hoses common? Can't remember seeing it before

Edited by edlithgow on 17/05/2020 at 15:38

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Sun 17 May 2020 19:29
Daihatsu Skywing - Electrolytic corrosion of pipe in hose - bathtub tom

Is corrosion of steel pipes by rubber hoses common? Can't remember seeing it before

I see quite a lot of it, but then I often work on cars over 100 years old. Just been dealing with a '35 Austin 7. The steel bolts holding the aluminium water manifold to the side of the cast iron block had corroded such that one had rotted completely and the other was only a couple of millimetres thick. Put a spanner on one and it sheared, then the thing fell off. No wonder it was leaking.

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Tue 19 May 2020 10:19
Daihatsu Skywing - Electrolytic corrosion of pipe in hose - edlithgow

The sealant I used "ENA 168 " was left behind by plumbing contractors a few years ago.

Seems to be pretty useful stuff, though I've no idea whats in it.

Pink stuff (A) smells acidic (acetic or formic. maybe) and the white stuff (B) doesn;t have much smell and probably contains talc or fumed silica.

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Any guesses as to what it might be? Doesn't seem to be an epoxy.

Google translate has "Enamax super strong piping enamel ENA-168 Contains nanometer ultra-fine particles molecules, which penetrates into the deep part of the coating and blocks cracks when exposed to heat.

Good adhesion, high toughness, thermal expansion and shrinkage without cracking and falling off. Acid and alkali resistance and cooling medium" but then they would say that.

Equivalent UK market products?

Edited by edlithgow on 19/05/2020 at 10:20

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