Sprenger pintles / pack with epoxy?

[Doug Hagan]

Folks

Sprenger pintles weakness: the weld at the bottom of the pin will rust and crack.  I have seen .5mm cracks in the upper webbing, in the corner where it bends to the flange.   The upper press fit has also loosened on one fitting, encouraged by weakened weld at the bottom of the pin.

Does it make any sense / difference to pack the inner void with filler and West Systems 105?  

Would this reduce the chance of rust, hold the pin more firmly and make the pintles last longer?  Or would it hide any impending failures?

I keep a close eye on these fittings and replace them whenever I see rust/crack  or just get nervous.  There's no guarantee that a new one won't fail out of the box either.

 I think I've seen folks (TeamSpot and others) pack the seasure-s with epoxy and filler.  This mitigates and reduces motion between the transom and the fitting?  I don't see that this applies to these fittings?

Thoughts?

--Doug

808-446-4881 (c)

[Brian Trainor]

Doug,

I look forward to reading comments written by those better educated in metallurgy than me.

But if you coat stainless steel in epoxy, it's my understanding that you block its access to oxygen, and therefore inhibit the formation of chromium oxide.

It's the chromium oxide that makes the stainless, stainless.

Wherever I have got epoxy on anything stainless, it makes a hell of a rusty mess in a couple of seasons.

I'd be pretty wary of getting it all over a pintle.

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[Paul Scoffin]

Correct, starving stainless steel of oxygen can lead to serious corrosion issues. A damp boat cover or similar can have an effect. Stainless steel pins through salt water laden sailcloth will result in the same outcome as with SS keel bolts. Pits or crevices are the worst areas as water pools there. 

Sent from my iPhone

On Sep 22, 2026, at 6:48 PM, Brian Trainor <bptr...@gmail.com> wrote:



Doug,

I look forward to reading comments written by those better educated in metallurgy than me.

But if you coat stainless steel in epoxy, it's my understanding that you block its access to oxygen, and therefore inhibit the formation of chromium oxide.

It's the chromium oxide that makes the stainless, stainless.

Wherever I have got epoxy on anything stainless, it makes a hell of a rusty mess in a couple of seasons.

I'd be pretty wary of getting it all over a pintle.

On Tue, Sep 22, 2026, 8:35 PM Doug Hagan <dhag...@gmail.com> wrote:

Folks

Sprenger pintles weakness: the weld at the bottom of the pin will rust and crack.  I have seen .5mm cracks in the upper webbing, in the corner where it bends to the flange.   The upper press fit has also loosened on one fitting, encouraged by weakened weld at the bottom of the pin.

Does it make any sense / difference to pack the inner void with filler and West Systems 105?  

Would this reduce the chance of rust, hold the pin more firmly and make the pintles last longer?  Or would it hide any impending failures?

I keep a close eye on these fittings and replace them whenever I see rust/crack  or just get nervous.  There's no guarantee that a new one won't fail out of the box either.

 I think I've seen folks (TeamSpot and others) pack the seasure-s with epoxy and filler.  This mitigates and reduces motion between the transom and the fitting?  I don't see that this applies to these fittings?

Thoughts?

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--Doug

808-446-4881 (c)

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