bronze fitting queery

[Sans Bateau]

Last year I fitted a new seacock and adaptor ( VP call it a nipple) to my saildrive. The nipple came from VP.

This year I had a reason to remove the seacock and nipple, but I noticed that there was a small area within the threads of the nipple that screw into the saildrive (ally) that were pink.

With all that we have learned over the last 12 months about brass and bronze fittings, its my understanding that pink indicates dezincification in brass. I have spoken to 2 VP dealers and both reckon that the fitting is bronze or DZR at least. At the price it was it ought to be gold!

I can refit the nipple but it is really difficult to undo at another time and the next time it may be because it has failed. Anyone got any suggestions?

 

[VicS]

Last year I fitted a new seacock and adaptor ( VP call it a nipple) to my saildrive. The nipple came from VP.

This year I had a reason to remove the seacock and nipple, but I noticed that there was a small area within the threads of the nipple that screw into the saildrive (ally) that were pink.

With all that we have learned over the last 12 months about brass and bronze fittings, its my understanding that pink indicates dezincification in brass. I have spoken to 2 VP dealers and both reckon that the fitting is bronze or DZR at least. At the price it was it ought to be gold!

I can refit the nipple but it is really difficult to undo at another time and the next time it may be because it has failed. Anyone got any suggestions?

1. I am astounded that a bronze or brass fitting is screwed directly into the aluminium alloy saildrive! But I suppose the saildrive is large and the nipple small.

2. I am surprised any dezicification would occur in a fitting screwed in to aluminium.

 

[prv]

Is there anything VP-specific about the nipple? Can you not just buy a definitely-DZR one from ASAP?

Pete

 

[Martin_J]

I bought the same part last year from Keyparts... to replace the plastic valve that was in the saildrive from new...

It is shown as the batch of parts #65B/C/D/E here...

Replacement water inlet valve on Volvo Saildrive

I did wonder at the time what it was made from but Keyparts did not say.

 

[Sans Bateau]

It was Keyparts that supplied mine, but I bought the nipple separately. I did ask them and Motortech and they both said bronze. At 30 quid youd expect it to be bronze. a male/male fitting in bronze from ASAP is £2.60!

 

[vyv_cox]

If it is definitely bronze it could be that you are seeing some sort of inter metallic reaction between bronze and aluminium. I assume that if this occurred it would be limited to a very thin surface layer. Diffusion of one metal into another often occurs, although more commonly at higher temperatures than seawater.

I have seen slight pinkness on DZR but again, only on the surface and it doesn't go further. Maybe an effect of the manufacturing process?

 

[Sans Bateau]

Thank you Vyv, that is reassuring.

 

[lw395]

Are you sure the pinkness is not some sort of threadlock or sealant?

 

[Martin_J]

My nipple might be pink.. I'll check shortly..

(I did use Jetlube V2 when I assembled it so it could well be coloured!)

I would have thought Galadriel might have remembered if he had used a pink sealant when he replaced his nipples last winter

 

[Sans Bateau]

Are you sure the pinkness is not some sort of threadlock or sealant?

PTFE tape.

Oh! White PTFE tape.

This time it will be black Sikaflex.