Prop "glazing" after cleaning with brick cleaner

Halo

Halo

Well-Known Member
Joined
10 Nov 2009
Messages
2,051
Location
Wetherby
Visit site
For a few years now I have cleaned up my flex o fold 3 blade prop with brick acid. The just dissolves away the crud and barnies leaving a beatiful shiny prop with no scratches and very little effort. Last year I noticed the prop was getting a hard smooth glaze finish on the blades - not simply smooth metal but a ceramic like smooth surface. This year its even better - almost a glass like surface a little darker than the original bronze. Has anyone else noticed a similar effect ?
 
Which type of brick cleaner?
I'm keen to give this a try and will donate my old fixed radice prop to try it out.
Can anyone advise what the chemical reaction could be that might cause this effect?
 
bignick said:
Which type of brick cleaner?
I'm keen to give this a try and will donate my old fixed radice prop to try it out.
Can anyone advise what the chemical reaction could be that might cause this effect?
Click to expand...

Its "Cementone Brick and Patio Cleaner" . The crud removed is a bit like water hardness and makes the prop feel rough. After removal its very smooth as described. Nothing special about the location/ water as this year and I went from Preston to Whitby via Scillies and S Coast and last year went from Glasson to Ireland and Wales, previous year from Whitby to Glasson via Calednoian Canal
 
MAURICE said:
My boat is in spain and I use aqua fuete which is the same as brick cleaner but slightly diluted i think.
Click to expand...

The Cementone data sheet states 5-10% hydrochloric acid.

Agua fuerte, which I presume is what you mean, is also hydrochloric acid - otherwise known as acido clorhidrico, spirits of salts, muriatic acid, and yet others. As sold in supermarkets and hardware shops, it would probably be in concentrations of maybe 10-15% or so. It should say on the bottle. (The percentages are a little misleading since the highest possible concentration under normal conditions is only around 37%.) Many proprietory toilet bowl cleaners also contain HCl, usually in the range of 10 to 15%.

'Brick/patio cleaner' is no more specific than 'toilet cleaner'. It often, but not always, contains HCl. Even 'brick acid' may contain acids other than HCl. (Industrial versions can even contain hydroflouric acid, which is very nasty stuff indeed.)
 
Last edited:
If you moor 'inland' as I did in Suffolk with as much river water passing your prop as sea water your prop will end up with that very thin concreting, where in Suffolk they call it 'shelling'.

Doesn't happen if you use the boat a lot - who has that luxury?

In the end, I had to using anti fouling.
 
I take it from the thrust of this thread that it's OK to use brick cleaner which I think is 5-10%hydrochloric on bronze and stainless steel; my daughter who has more knowledge of chemistry than me thinks it should be OK on cast iron keel also.
 
eddystone said:
I take it from the thrust of this thread that it's OK to use brick cleaner which I think is 5-10%hydrochloric on bronze and stainless steel; my daughter who has more knowledge of chemistry than me thinks it should be OK on cast iron keel also.

Just read the label and it says don't use on stainless steel
Click to expand...

As said in post #6, 'brick cleaner' is not at all specific. It may contain HCl, it may not. The label or data sheet should tell you.

As I think Vyv Cox has written, there should be no great problem in cleaning carbonacious crud from stainless with HCl, providing you just clean it rather than dump it in it for extended periods. I suspect there may, however, be a cosmetic issue with polished stainless (which you might not care about if the component lives underwater). Certainly regular use of oxalic acid can sometimes 'etch' the surface of stainless to the extent that it loses some of its gleam; the same may be true of HCl. It's also possible that it has an effect on passivation of welds: afraid I don't know.
 
I would not expect hydrochloric acid to produce a brown glaze - although CuCl2 is brown, it becomes green on hydration – and the hydroxy chlorides (like atacamite and botallackite, Cu2(OH)3Cl) are also green minerals. Artificial brown patination on brass, bronze and copper seems typically, but not exclusively, to involve iron: http://www.sciencecompany.com/Patina-Formulas-for-Brass-Bronze-and-Copper.aspx#1.

I just get a light calcareous deposit on the prop, plus a few barnacles, which scrapes off (or dissolves with acid), following which I polish. Your glaze sounds rather less boring - though it does not seem as if it deters the 'crud' formation!
 
You must log in or register to reply here.

Share this page

Top