Chainplates from grainger

[malbert73]

Originally Posted by VinnyVincent

Alright you guys convinced me, dremel tool is out.



I didn't realize I would need to use so much pressure. I also have an angle grinder, but I will look into renting a real deal polisher as well.



I know it seems like I'm being super cheap(and I guess I am), but this will not be my last boat. It's just a little beater I bought to get the hang of cruising and maintaining a cruising boat. I plan on selling in the next 5ish years for something in the 40ft range...

This is key. Not your last boat. Do your best. They are 316 so better than par. Chainplates should be inspected every handful of years anyway. Doubtful anyone will cross oceans in that boat so what you are doing is an upgrade no matter what.


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[VinnyVincent]

Originally Posted by Cheechako

Lookin good!

Thanks man I appreciate you nudging me in the direction of doing it all myself. It really wasn't bad at all. I probably got more of a headache trying to find a local place to polish it with a decent turn around time.

I'm sure a professional could have done a better job, but I don't think it would have been all that much more effective for corrosion resistance than the job I did.(short of more aggressive techniques like electropolishing) There are some small imperfections where I didn't quite get all the scratch's out, but for the most part it is smooth as glass. I paid special attention to detail on the areas that will/could be exposed to seawater.
I also scrubbed it down twice with bar keepers friend. It's a technique used in home brewing, in an effort to get the oxalic acid contained in the bar keepers friend to "passivate" the stainless.

Hopefully this will be "good enough" and I am thinking another key factor is how well I seal them, which is more fun I have ahead of me.

[Stumble]

Vinnie,

Now that the polishing is finished I would really suggest passivating the parts. Nitric acid is preferred, but isn't really available to a home user because it is so caustic. Instead mix up a bucket of 7% (by weight) citric acid and distiller water. The citric acid should be readily available at any home brewing shop, or commercial kitchen supply place.

Drop the parts in and let them soak for 2 hours or so. This will remove the free iron on the surface of the metal.

And because citric acid is food safe you can pour it down the drain (just heavily dilute it first please).

[VinnyVincent]

Originally Posted by Stumble

Vinnie,

Now that the polishing is finished I would really suggest passivating the parts. Nitric acid is preferred, but isn't really available to a home user because it is so caustic. Instead mix up a bucket of 7% (by weight) citric acid and distiller water. The citric acid should be readily available at any home brewing shop, or commercial kitchen supply place.

Drop the parts in and let them soak for 2 hours or so. This will remove the free iron on the surface of the metal.

And because citric acid is food safe you can pour it down the drain (just heavily dilute it first please).

Thanks Greg I might try that...In fact I think I have some citric acid laying around from the last batch of wine I made.
I did make up a paste of bar keepers friend and I rubbed the on there, but I am wondering how effective it is, since BKF is only 7-10% oxalic acid. I read where this technique is widely used in home brewing, but I'm not sure it's good enough for marine use.
I will probably try your method to be sure.

[Stumble]

For really caustic environments (like the sea) citric acid passification is generally considered a minimum. But like I said nitric acid is rough stuff to mess with. The problem with a paste is the boundary surface can get clogged with iron molecules and won't disperse, so there can be an uneven reaction. A big bucket that can be swirled around from time to time is crude, but effective.

[VinnyVincent]

Okay, I got my citric acid crystals. Any reason not to throw the hardware into the tub with the plates?

[Cheechako]

Originally Posted by VinnyVincent

Okay, I got my citric acid crystals. Any reason not to throw the hardware into the tub with the plates?

FYI: I suspect that using acid at this point will dull the finish some. Although it may be easy to get the mirror back after.

[model 10]

Originally Posted by VinnyVincent

Okay, I got my citric acid crystals. Any reason not to throw the hardware into the tub with the plates?

Use warm water. The dulling is very minor. I use 1/2 lb per gallon. It's enough to sting under your finger nails.

[Stumble]

Originally Posted by VinnyVincent

Okay, I got my citric acid crystals. Any reason not to throw the hardware into the tub with the plates?

I would suggest dissolving the crystals first, it's just easier. A paint stirrer on a cordless drill works a treat.

[VinnyVincent]

Soaked them last night. It's be a lie if I said it seems like it did anything.
The finish was affected a little, but it's borderline noticeable.

Anyhow I did some research and used a method that Boeing uses for their aerospace stainless. 15% solution for 2 hours at ambient temp.

You can read up on it here: Passivating stainless 304 brew vessels (Page 1) - General Discussion - Finishing Talk Forums - The Online Surface Finishing Community


So, I took 1.25lbs of citric acid, a gallon of distilled water and a large, flat container. It ended up looking like the this:




After 1 hour, I flipped the parts and I also continually agitated it by rocking the container back and forth.


Now that the steel is done, I get to go replace the old rotted core near the holes in the deck with thickened epoxy...right in time for heavy rain/wind in the forecast.

[Stumble]

Yea the visual effects are minimal. Even under ideal conditions with nitric acid you are only removing a few (2-3) molecules deep layer of iron. But the chemical difference is huge.

[VinnyVincent]

Another update here. I got one side done relatively easy. Used a router to cut away some of the balsa core and replaced the core with west systems six10 thickened epoxy. I bolted the chain plate in place, only covered with grease so that the epoxy could form a "perfect fit" around the chain plate. Here's how it came out:



That was easy right? Maybe this whole chainplate thing wasn't so bad afterall? WRONG!



This is what the core looked like on the opposite side of the deck after I eventually took a screw gun, with an allen key and a vacuum cleaner and went to town clearing out the 3" of core surrounding the chain plate. Now that it is cleared out, just refill with epoxy, right? WRONG!

As soon as I got the caulk gun loaded and squirted the first little bit of epoxy into on of the holes, the caulk gun broke
So I run to home depot with the epoxy in the fridge, trying to slow the curing process down.
I get back and it starts pouring down rain. For hours

Now here we are two days later. I am heading over after work in hopes that the holes has dried enough for the epoxy to at least stick to the hollow glass near the chain plate.
That good deal I got on this boat isn't sounding so good now lol

[Cheechako]

yep, sounds like boat work to me!

[Stumble]

Sounds about right... At least you know you have stopped the core rot and can sleep safely at night.

No matter what project I have on a boat I always assume something is going to go wrong... its like a guessing game. Sometimes I guess right, most of the time I have to take additional trips to the store.

[lifeofreilly57]

Gar Hauer now makes chain plates to order, they can copy from your originals. By the time you figure your labor and the polishing it.might be a wash.

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