What is the white powder?

[Ed Nye]

Rich VanValkenburg and I have the same question. What is that white powder that forms on the lead keel around the stainless bolt pockets? I have always been told that stainless suffering from stagnant water corrosion weeps a black gunk. So what is the white powder? Lead oxide you put on your nose is white; is it that?
Ed

[mark g]

i believe what is put on your nose is zinc oxide. The white powder might be a chemical reaction from the two dissimilar metals with the salt water acting as electrolite

[Dave Fleming]

I have observed SS fasteners will develop a whitish crust when used to fasten AL fixtures on a vessel. Been told that is a chemical reaction between the SS-AL and salt air. Mighten the same thing be happening between the SS and the Lead in the salt water?

[Rich VanValkenburg]

My boat hasn't seen salt water since 1936. She's a fresh water boat.

Rich

[ 10-14-2002, 05:02 PM: Message edited by: Rich VanValkenburg ]

[Dave Fleming]

Well that half arsed thesis goes down in flames. redface.gif

[Bob Adams]

If you have suspicious white powder on your boat I suggest you keep your distance from the Coast Guard! :rolleyes:

[Frank Wentzel]

The white powder would be lead chloride if there is salt water present. If not is should be lead oxide (litharge) or lead carbonate (white Lead). Lead carbonate will fizz slightly on contact with a drop of muriatic (hydrochloric) or sulfuric acid. Lead oxide is soluble in warm vinegar (Acetic acid) forming lead acetate (sugar of lead). Lead chloride is not very soluble in cold water - on the order of 0.6 grams per liter - but it is relatively soluble (3.5 grams per liter) in very hot water. Lead oxide will not dissolve in water.

In other words, depending on the exact conditions, you have one of several lead corrosion products present. Do not panic! It is not particularly dangerous, regardless of the apparent panic that several agencies and businesses, that are currently making a living off lead, are trying to instill in us. Just don't eat without thoroughly washing your hands after handling the lead. Also, avoid breathing any dust from this area. The minimum oral acute toxic dose of lead is on the order of ten grams. However, lead does bio-accumulate, so reasonable care is warranted.

/// Frank ///

[DragonFly]

Frank, does that include the white stuff mentioned above that someone was putting on their nose? lol

Thanks for the breakdown on how to do a simple test to see what we might have. After reading your response I believe the 'white stuff' I have has been caused by the rain water sitting in the hull and seeping down the keel bolts. That would explain why it's seemingly inside the ballast and why it's worse at the cracks from where it was poured at different times. Probably has some rust in there as well. Looks like I better start collecting some tire balance weights and do a repour for sure!

Thanks again, Louis

[PeterSibley]

Does the white powder fizz if you pour a bit of white vinegar on the wood and it ? If so it could be the beginnings of electrolysis (spelling ?) Seek professional advice and find the article on "Gauntlet "in WB ,pretty old ,around no.54 as I remember.