Stainless or Titanium?

[Delancey]

Did some titanium anodizing in school. Can get a range of colors by varying the voltage. Not that you would want to. Just saying.

[a64pilot]

Originally Posted by Terra Nova

Don't use a rubber gasket under a chain stopper.

4200 should be fine.

I think he meant just around the edge, or I took it that way anyway.

[Terra Nova]

The stainless anti-chafe plate should be firmly attached to whatever is beneath it, as the chain stopper bears directly against it. Bed it solidly so it cannot move about. Make the stopper holes a net fit so the chafe plate takes the side loading.

[Jim Cate]

TN, I'm curious as to your thinking:

Functionally, how is a thin (~0.5mm) rubber gasket different from a thin (~0.5mm) layer of elastomeric sealant like 4400 or similar? Both would allow minor movement of the chafe plate, both would keep water out, neither one would do much to improve the shear strength of the stopper attachment... or at least that's how it looks to me.

The big difference IMO is that the sealant would bugger up the teak decking under it and maake removal of the chafe plate difficult.

Jim

[Terra Nova]

The big difference is that 4200 would bond the chafe plate to the substrate, helping to prevent movement of the stopper, if installed as I suggested.

4200 can be de-bonded. So there should be no concern about the teak beneath. Though I cannot understand this concern at all.

[Jim Cate]

Originally Posted by Terra Nova

The big difference is that 4200 would bond the chafe plate to the substrate, helping to prevent movement of the stopper, if installed as I suggested.

4200 can be de-bonded. So there should be no concern about the teak beneath. Though I cannot understand this concern at all.

OK, if the stopper is not bonded to the chafe plate, how is the bond between the plate and the deck helping prevent movement of the stopper? Seems like it is the through bolts that clamp the stopper to the deck structure that prevent the movement, not the chafe plate.

But no use in arguing, I was just curious...

Jim

[Terra Nova]

Originally Posted by Terra Nova

...Bed it solidly so it cannot move about. Make the stopper holes a net fit so the chafe plate takes the side loading.

Originally Posted by Jim Cate

OK, if the stopper is not bonded to the chafe plate, how is the bond between the plate and the deck helping prevent movement of the stopper? Seems like it is the through bolts that clamp the stopper to the deck structure that prevent the movement, not the chafe plate.

But no use in arguing, I was just curious...

Jim

See previous post.

[Jim Cate]

Originally Posted by Terra Nova

See previous post.

How does a very thin bit of sheet metal take the side loading from the bolts? Seems like the ~1 inch thickness of the deck is what does that, even if there is a 100% contact hole in the sheet metal.

Jim

[Terra Nova]

I thought you were once an engineer. And so should not need me to explain something so pitifully obvious.

But for those who are not engineers, take my word for it. The enormous bonded area will prevent the stainless chafe plate from moving. And the relatively thin section of stainless is tightly sandwiched between the stopper and the deck.

The teak substrate, by itself, is very soft. And the bolt holes can easily be deformed by expectedly heavy side loads.

[Jim Cate]

Originally Posted by Terra Nova

I thought you were once an engineer. And so should not need me to explain something so pitifully obvious.

But for those who are not engineers, take my word for it. The enormous bonded area will prevent the stainless chafe plate from moving. And the relatively thin section of stainless is tightly sandwiched between the stopper and the deck.

The teak substrate, by itself, is very soft. And the bolt holes can easily be deformed by expectedly heavy side loads.

No, TN, I was in a previous life a physicist, and subject to all the ills of that trade. This includes an enquiring mind, one that questions categorical statements like "Don't use a rubber gasket under a chain stopper", especially when that was not suggested. (the gasket being between the chafe plate and the deck, not between the stopper and the plate)

But my pitiful knowledge says that the deck isn't teak, the deck is fibreglass with a thin teak overlay, and the bolts side loads will be absorbed mostly in that layer. That very soft teak that you dislike is what the plate, if bonded, would be attached to. And as you mention the stainless is "tightly sandwiched between the stopper and the deck". The high clamping force between stopper and deck is there with or without bonding, and the friction added by a thin rubber gasket isn't zero, so it isn't going to be sliding around with every pull on the stopper.

I will agree that there is some support offered to the bolts by the plate. I'm not convinced that the bonding adds that much to the picture. If the OP had not wanted the chafe plate, it is likely that he would have mounted the stopper directly on the deck as most folks do... likely would have been ok. And remember, typical deck cleats are simply mounted directly on the deck with no intermediate sheet metal, and they seem to survive large horizontal loads pretty well, even on timber decks made of "very soft teak". And their normal footprint is much smaller than that of a chain stopper...

So, it appears that we will continue to disagree on this, and that's ok. The OP will mount it however he wishes, and I bet it will be ok, too.

Jim

[Terra Nova]

Have it your way. If anyone thinks it's a good idea to place a rubber gasket beneath a plate on which a chain stopper is mounted, they at least have your support. We disagree.

[delmarrey]

I'm not voting for Hillary or Trump.