HCl to clean SS props

[DavidJ]

Had an antifouling week (in Sardinia) last week and although it was my intention to DIY, I decided to pay up and watch others. To clean the barnicles off the SS props and parts of the leg, the guys used 30% HCl, yes Hydrochloric Acid!. They dabbed it on with a stick with a pad on the end. The barnicles just bubbled off and the material was left untouched. It seemed most effective. Is this a Sardinian thing or have others come across the practice.
Health Warning: I suspect Al props might just dissappear under the same treatment.
David

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[peterandjeanette]

Nothing wrong with using a little hydrochloric acid to clean stainless steel. The worst it will do is remove the chrome oxide coating from the surface. As soon as it is washed off the chromium content of the steel oxidises again immediately and forms the passive surface. This is what makes stainless steel stainless. (The only way to "pickle" stainless is with a mixture of nitric and hydrofluoric acid. Not the sort of thing that the average boat owner keeps in the engine room - or anywhere else for that matter.)

Definite no-no on aluminium. The only time aluminium should come into contact with an acid is in controlled electronic processes with sulphuric acid. This is the basis of anodising.

All the above IMHO as a metal finisher!!!

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[Tiger Rag]

we use it over all the time as well, also works well on brass props. You can buy it really cheaply in most hardware shops for about €3 a litre called aqua fuerte (strong water).

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[jfm]

strong stuff in med

Sounds good. I think much easier to buy strong stuff retail in Med than UK. Last summer TCM needed some decent acid and came back from chandlers with 1 litre bottle of quite conc sulphuric acid. When he splooshed it about the smell of sulphur was incredibly strong. Rubber gloves and goggles time. Jeans dissolved off people at 20 paces. Whereas in UK it would be 100 times more dilute than this

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[tripleace]

Re: strong stuff in med

I need to clean ss props on Triple Ace.

Concerned about acid.

Is it safe to dab on a hose off?

what sort of gloves

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[jfm]

Re: strong stuff in med

I dont know really. If it's slime then bleach will help remove it. If it's more stuck on then sulphuric acid will work becuase it attacks organic stuff well, but really I dont know if acid etc will damage your metals or seals, sorry. Anyway, it's hard to get conc acids retail in UK. People use ordinary pvc type gloves for even strong acids, I think

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[ArthurWood]

Re: strong stuff in med

Chlorine solution for green stuff, if it wont rub off - leave on till stuff dies then wash off. Don't breath fumes - they attack mucous membranes.
Hydrochloric acid for barnacles-leave on till barnies gone then wash off
Use rubber gloves, but main thing is to protect your eyes from splashes. If you get an acid splash in your eye (you will know it if you do) immediately turn hose on your eye and flood with water. If any pain persists, see a doctor.

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[Bejasus]

2 things.
1. Do you know how volatile Nitric Acid can be in contact with water.
2. Hydrofluoric Acid is one of the deadliest substances around. I work with it in offshore environments and we have to carry a special injection kit as an antidote. It is that bad it can gradually destroy your organs from within over a period of years.

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[tripleace]

Remembered a few years ago I bought and put in a cupboard a sand blasting attachement for my water pressure cleaner.

That has got to be a whole load safer than playing with chemicals.



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[DavidJ]

You're right but it is fun watching barnacles fizz away
David

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[peterandjeanette]

Highly doubtful that any Tom, Dick or Harry could get their hands on Hydrofluoric Acid. We only use it in small quantities in the laboratory not on the factory floor. Personally, I won't go any where near the damn stuff, except in its cabinet for etching small samples of stainless steel.

Note that several forumites quoting use of sulphuric acid. Remember to add the acid to water for dilution and not the other way round.

Glad to see use of P.P.E. (personal protective equipment) highly advised.

This is getting a bit technical. I use the boating side of my life to escape from the factory. Nothing like a bit of fresh air after a week of chemicals.

Best advice. Stay away from concentrated chemicals unless properly trained.



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[tripleace]

agree with comment however

local chemist was willing to sell me 2 litres for £5.00 on Friday. Desided against doing a re-run of Batman and Joker (chemical spill)

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[Bejasus]

Separately the chemicals constituents of HF Acid are reasonably easy to get hold of.

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[ArthurWood]

and don't store HF in a glass bottle!

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