Pear anode removing the white deposit

[davidmh]

Every year when the boat is hauled out the pear anode has patches of erosion which are grey and obviously active, but there is alot more of the anode which is pitted but is covered with a white hard deposit, you can chip it off to get to the bare metal. Could you dissolve the deposit if you removed it from the hull first. Would brick cleaner be effective.

David MH

 

[vyv_cox]

Brick cleaner would be effective at removing the deposit, but even more effective at removing the zinc anode. You should clean up anodes using something non-ferrous, either abrasive discs in a grinder or a brass wire brush. Small amounts of iron in the surface of an anode can inhibit its performance.

 

[VicS]

Every year when the boat is hauled out the pear anode has patches of erosion which are grey and obviously active, but there is alot more of the anode which is pitted but is covered with a white hard deposit, you can chip it off to get to the bare metal. Could you dissolve the deposit if you removed it from the hull first. Would brick cleaner be effective.

David MH

I assume the boat is moored in salt, not fresh or brackish water therefore thinking your anode may not be very active from what you say. It might be a good idea to check the bonding to whatever it is fitted to protect.

 

[johnalison]

An old anode re-immersed into salt water can take up to two weeks to become active again, so I was told. The answer suggested was to abrade the anode so that mostly bright metal was showing, and that the untreated parts would become active again eventually.

 

[Stork_III]

An old anode re-immersed into salt water can take up to two weeks to become active again, so I was told. The answer suggested was to abrade the anode so that mostly bright metal was showing, and that the untreated parts would become active again eventually.

Volvo Penta instructions which come with new prop and leg anodes, recommends abrading before use to remove oxidation since casting.

 

[johnalison]

Volvo Penta instructions which come with new prop and leg anodes, recommends abrading before use to remove oxidation since casting.

I've not seen that, though, like most people, I don't read instructions until something goes wrong. It sounds reasonable, but I would think not strictly necessary if the metal looks bright.

 

[GrahamM376]

Brick cleaner would be effective at removing the deposit, but even more effective at removing the zinc anode.

In common with several others, I drop mine into 30% hydrochloric acid (available in diy stores in Portugal) for a couple of minutes, lots of bubbling then wash in water and they come out nice and clean.

 

[RichardS]

In common with several others, I drop mine into 30% hydrochloric acid (available in diy stores in Portugal) for a couple of minutes, lots of bubbling then wash in water and they come out nice and clean.

30% is very strong HCl and I would have thought that in a couple of minutes you would have lost a lot of anode unless you mean a 30% dilution of household HCl which is usually 10 - 20% HCl.

Richard

 

[Sinbad1951]

Use a brass wire brush in a drill. It will soon remove the calcium build up on the anode.

 

[GrahamM376]

30% is very strong HCl and I would have thought that in a couple of minutes you would have lost a lot of anode unless you mean a 30% dilution of household HCl which is usually 10 - 20% HCl.

Richard

No, this is 30% concentration HCL, off the shelf, used out of the bottle. No sign of any loss to the anode just turns the surface grey. Works well on rope cutters as well, come out like new with any barnacle glue gone.

 

[vyv_cox]

No, this is 30% concentration HCL, off the shelf, used out of the bottle. No sign of any loss to the anode just turns the surface grey. Works well on rope cutters as well, come out like new with any barnacle glue gone.

VicS is the authority but AFAIK 30% is almost maximum concentration. HCl is a gas that dissolves in water to a maximum of about 32%. Seems like powerful stuff for your average housewife to throw around.

 

[VicS]

VicS is the authority but AFAIK 30% is almost maximum concentration. HCl is a gas that dissolves in water to a maximum of about 32%. Seems like powerful stuff for your average housewife to throw around.

IIRC Laboratory conc hydrochloric acid is 36% but it is unpleasant and somewhat dangerous to handle in any quantity due to the fumes of hydrogen chloride.

For cleaning anodes or general descaling I'd suggest diluting to between 5 and 10%.

 

[GrahamM376]

VicS is the authority but AFAIK 30% is almost maximum concentration. HCl is a gas that dissolves in water to a maximum of about 32%. Seems like powerful stuff for your average housewife to throw around.

All I know is what it says on the bottle, just done a quick Google and available here (UK) quoted as 32%. http://www.farmchem.co.uk/hydrochloric-acid-32-25-litres-123-p.asp?gclid=COnf3ebxlMgCFWkOwwodD2oN_A

Chemistry not my strong point, according to my school reports I was only interested in explosive compounds

 

[Kurrawong_Kid]

All I know is what it says on the bottle, just done a quick Google and available here (UK) quoted as 32%. http://www.farmchem.co.uk/hydrochlo... are reported to be interested in explosives!

 

[Heckler]

All I know is what it says on the bottle, just done a quick Google and available here (UK) quoted as 32%. http://www.farmchem.co.uk/hydrochloric-acid-32-25-litres-123-p.asp?gclid=COnf3ebxlMgCFWkOwwodD2oN_A

Chemistry not my strong point, according to my school reports I was only interested in explosive compounds

I love the Jumbo in Faro, all sorts of interesting bottles of "cleaning" agents on the shelf! I mean can you believe that they actually sell 30% HCL acid in litre bottles? Put it in the basket and go checkout!
Going on to your school boy interest, as school kids we used to go to a pharmacy in King St in Wrexham, please sir can we have an ounce of potassium nitrate and a couple of ounces of sulphur please! The charcoal we used to get by powdering BBQ charcoal!
Stu

 

[rogerthebodger]

I can go to any supermarket and buy 5 litres of 30% HCL sold as pool acid to correct the acidity of swimming pool water.

I have 5 litres on my boat at the moment used to remove rust spots on my steel deck followed by Phosphoric acid then paint.

 

[Robg71]

once you have dissolved your zinc anodes in the HCL, makes zinc chloride, fantastic for soldering with, better than any shop bought flux...

 

[[29051]]

The advertising of the concentration of the acid is often confusing. It's the units that matter and they are often not mentioned apart from in the safety data sheet. If the acid is sold as 10% hydrochloric acid it is usually v/v (volume/volume) ie concentrated hydrochloric acid diluted 1:10 by volume. The concentrated acid contains about 37% hydrochloric acid by weight. So the 10% solution actually contains about 3.7 % hydrochloric acid.

 

[Malish]

The advertising of the concentration of the acid is often confusing. It's the units that matter and they are often not mentioned apart from in the safety data sheet. If the acid is sold as 10% hydrochloric acid it is usually v/v (volume/volume) ie concentrated hydrochloric acid diluted 1:10 by volume. The concentrated acid contains about 37% hydrochloric acid by weight. So the 10% solution actually contains about 3.7 % hydrochloric acid.

Spot on

 

[GrahamM376]

Going on to your school boy interest, as school kids we used to go to a pharmacy in King St in Wrexham, please sir can we have an ounce of potassium nitrate and a couple of ounces of sulphur please! The charcoal we used to get by powdering BBQ charcoal!
Stu

Off topic I know but, sadly times have changed and it's 54 years since school and I parted company. Kids can no longer blow tree stumps out or make fireworks, would most likely get arrested for having items of use to a terrorist or some such nonsense. Can't nip down to the post office either aged 14 for a 10 bob shotgun license.:sorrow: