Well hell...damn iPad auto correct
Brion,
The PTF chainplates are made from manganese bronze. They are stronger than 316.
I have decided to get new rigging pieces instead of milling down to 1/4. The milling would have been expensive because of the convuluted shape of the CP. plus I don't trust the shop that broke the first ones or the other shop here. But I have also purchased some nylon washers used for insulating dissimilar metal parts, and I will also slather on some Tef-gel.
A quick comparison between M bronze...
Minimum Properties Ultimate Tensile Strength, psi 119,000
Yield Strength, psi 66,700
And SS 316
Minimum Properties Ultimate Tensile Strength, psi 89,900
Yield Strength, psi 60,200
So at twice the size needed I guess I have a very large error of neglect.
this manganese situation is very disappointing. I spent good money on "bronze" so I could basically neglect them. But that doesn't seem to be the case now. No doubt they are strong. But the zinc component is troubling. Pete was very concerned that I would be using his chainplates w/aluminum fittings. I didn't understand that at the time. But seeing the zinc content now I do.
I'll just have to keep an eye on them. But what happens if one of my boomkin chainplates is submerged for 22 days on a trip to Tahiti?
Cheers Brion, and thanks for the imput.
Gary