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USnavy


Dec 22, 2011, 3:00 AM
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Polishing bolts to increase their corrosion resistance in marine environments?
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At least one manufacturer of marine grade glue-in bolts polishes the exposed parts of their bolts. Polishing the bolt makes sense, it makes for a smoother profile which reduces the chance of salt crystals sticking to the surface of the bolt, and all the like.

I bought some 316SS Wave Bolts and I am considering polishing the exposed parts of the bolt before installing them in an effort to extend their lifespan. I am wondering what specific type of polish and/ or buffing compound should be used. I know some SS polish can actually promote pitting and I dont want to inhibit the passivization coating on the SS, making things worse. So there is a lot to consider.

Does anyone have any recommendations for this process?


(This post was edited by USnavy on Dec 22, 2011, 3:02 AM)


bill123


Dec 22, 2011, 5:18 AM
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Re: [USnavy] Polishing bolts to increase their corrosion resistance in marine environments? [In reply to]
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I thought SA bolts have corroded rapidly in a marine env.


mattm


Dec 22, 2011, 9:31 AM
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Re: [USnavy] Polishing bolts to increase their corrosion resistance in marine environments? [In reply to]
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Bolt Products passivates their bolts (I assume that's who you're referring too). Note that 316SS won't be that great in nasty marine environs. I'm betting you know that too though...
Bolt Products use Duplex SS in their marine bolts.

The Wave Bolts do look a bit rough when you get them compared to Titt bolts. I do a bit of cleaning up as well to help with corrosion resistance.

I'm working in smaller batches of 20 or so. I use Barkeeper's Friend (oxalic acid) to clean and passivate. I simply scrub them with a rough sponge with water and the Barkeeper's stuff. Polishes them right up. I've also used the stuff to clean up SS hangers that have rust stains on them from PS washers. They look like new when done.

If I were doing larger numbers of bolts, I'd look into running them all in a dishwasher with citric acid (look for dishwasher cleaner) Same idea. You still might need to do some spot scrubbing if there's real dirty spots.


Before


After


(This post was edited by mattm on Dec 23, 2011, 8:22 AM)


tolman_paul


Dec 22, 2011, 9:51 AM
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Re: [USnavy] Polishing bolts to increase their corrosion resistance in marine environments? [In reply to]
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Your best bet would be to tumble them in a polishing media.


USnavy


Dec 23, 2011, 2:31 AM
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Re: [mattm] Polishing bolts to increase their corrosion resistance in marine environments? [In reply to]
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mattm wrote:
Bolt Products passivates their bolts (I assume that's who you're referring too). Note that 316SS won't be that great in nasty marine environs. I'm betting you know that too though...
Bolt Products use Duplex SS in their marine bolts.
Yep, I am referring to Bolt Products. I know 316 is not the best grade you could use in nasty marine environments, fortunately our marine environment is a bit less harsh than others' such as Thailand. Yep, their Sea Water Series bolts are made out of 2205 SS. We normally use titanium here. I am just exploring a few different options.

I bought the Barkeeper's Friend and I will give it a try. However I am trying to treat new bolts, not used ones. I wanted to polish them in an effort to maximize their life before installation. I looked at the picture of the 2205 bolts listed on Bolt Product's website. In the picture it appears the exposed part of the bolt is shinier than the rest of the bolt. This implies they buff it. It seems like a good idea, but will generic stainless steel buffing clay do the trick, or will that do more harm than good?

As far as the passivization with oxalic goes, I have always wondered if oxalic actually passivates SS or not.

The link below shows that 300 series SS should be passivated with nitric acid and critic acid, with a submersion time of 30 min in each bath and each bath needs to be heated.

http://www.mmsonline.com/...tainless-steel-parts


(This post was edited by USnavy on Dec 23, 2011, 2:53 AM)


USnavy


Dec 23, 2011, 2:32 AM
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Re: [bill123] Polishing bolts to increase their corrosion resistance in marine environments? [In reply to]
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bill123 wrote:
I thought SA bolts have corroded rapidly in a marine env.
SA bolts?


bill123


Dec 23, 2011, 5:38 AM
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Re: [USnavy] Polishing bolts to increase their corrosion resistance in marine environments? [In reply to]
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Sorry. I meant SS (stainless )


Partner j_ung


Dec 23, 2011, 9:22 AM
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Re: [USnavy] Polishing bolts to increase their corrosion resistance in marine environments? [In reply to]
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USnavy wrote:
Yep, I am referring to Bolt Products. I know 316 is not the best grade you could use in nasty marine environments, fortunately our marine environment is a bit less harsh than others' such as Thailand. Yep, their Sea Water Series bolts are made out of 2205 SS. We normally use titanium here. I am just exploring a few different options.

Just curious, but why stray from what you know works?


JimTitt


Dec 23, 2011, 1:23 PM
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Re: [USnavy] Polishing bolts to increase their corrosion resistance in marine environments? [In reply to]
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We hand polish the exposed part of our 1.4462 bolts as the polishing smooths the surface and gives less chance of crevice corrosion than just passivating. The whole bolt is pasivated first.
We could electro-polish the whole bolt which solves the corrosion problems but the surface is smoother so less adhesion for the glue so we leave the rest of the bolt passivated.
Oxalic acid is o.k for cleaning rust but is not used for passivating to the AISI standards, only nitric/suphuric acid mixes and citric acid are listed as far as I can remember. Using nitric acid is pretty environmentally unacceptable in Europe as well as being an additional industrial hazard and is difficult to transport.
We use citric acid in conjunction with tumbling in wet ceramic abrasive as the acid is bio-degradeable, cheaper and safer. The chemical composition and ph value of the rinse water is important as well to promote rapid oxide formation.

The relative value of all the different treatments is much discussed in the finishing industry but hand polishing is generally considered the best treatment for worked products to close the micro-cracking on the surface (with the right wheel and polish you are removing the softer elements on the alloy and smearing the chrome over the pores, you need a 600X microscope to check this is being done properly).

There are a number of tests in the standards for the success of the treatment, which one you choose is also debatable and usually one creates ones own test (we use the standard copper sulphate test and a 30 day brine spray). And then climbers hit them in with steel hammers and wonder about the rust marks, such is life!

Jim


sween345


Dec 23, 2011, 3:31 PM
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Re: [USnavy] Polishing bolts to increase their corrosion resistance in marine environments? [In reply to]
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  Navy,

This might interest you: http://www.climbcaymanbrac.com/?page_id=28


USnavy


Dec 23, 2011, 7:59 PM
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Re: [sween345] Polishing bolts to increase their corrosion resistance in marine environments? [In reply to]
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sween345 wrote:
Navy,

This might interest you: http://www.climbcaymanbrac.com/?page_id=28
Thanks for the link. I have seen my fair share of SSC and pitting, its scary stuff. Fortunately our environment is a fair bit less harsh than Thailand so we do not see the same level of problems that they do.
j_ung wrote:

Just curious, but why stray from what you know works?
I regularly place different bolts in different parts of the island for research purposes. This is an ongoing project that I have been conducting for a couple of years now. I have a number of rocks sitting next to the ocean with a wide variety of bolts installed in them. I conduct long term studies on the suitability of different alloys of stainless steel and different types of bolts. After a certain amount time has elapsed I pull test them to see how strong they are.

There are conditions in which titanium is not necessary required. I am trying to figure out if we need to use Ti bolts on routes that are well inland. If we did not have to use Ti on inland routes we could halve our bolting costs for those routes. That is part of what my research is about. Currently it costs well over $100 to bolt a single route. So if we can safely use a less expensive alloy further inland, than that helps everyone.

So ultimately these bolts are just another in a long series of tests. I just want to make sure I prep them correctly to maximize their potential. These bolts seem promising which is why I am giving them special attention and taking the extra time to polish them and all the like.

But ultimately, Ti or 2205SS is the way to go for serious environments.


(This post was edited by USnavy on Dec 23, 2011, 8:18 PM)


Partner j_ung


Dec 24, 2011, 8:35 AM
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Re: [USnavy] Polishing bolts to increase their corrosion resistance in marine environments? [In reply to]
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Interesting! Looking forward to learning how it turns out.


USnavy


Dec 30, 2011, 1:21 AM
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Re: [j_ung] Polishing bolts to increase their corrosion resistance in marine environments? [In reply to]
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Well I just finished the passivation of 40 of the 316SS Wave Bolts. I followed the directions given here: http://www.mmsonline.com/...tainless-steel-parts

I started by thoroughly washing the parts in water. I than soaked the parts in a 11% concentrate anhydrous citric acid solution that was heated to 150 degrees Fahrenheit in a kettle made out of stainless steel (assuming 304). The bolts were allowed to stand in the solution for 32 minutes. Lastly, I rinsed the parts in water and wiped them off with a cloth. Next I am going to polish them.




As you can see from the picture above, quite a bit of crap came off the bolts. I thoroughly washed and wiped the parts before they entered the bath, so the bath was solely responsible for lifting the grit you see on the cloth.

The manufacturer of the Wave Bolt tells me the parts are not pacified, but they are cleaned of shop debris before they are sent out to the customer.


(This post was edited by USnavy on Dec 30, 2011, 4:13 AM)


sungam


Dec 30, 2011, 2:59 AM
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Re: [USnavy] Polishing bolts to increase their corrosion resistance in marine environments? [In reply to]
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Not only is this interesting, but I think it's rad that you are going through the effort to give the kit your placing longevity. Much more responsible then a lot of equippers I can think of.


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