I hate stainless steel! (rant)

[Duvie]

Just dove into the bowels of the sailboat to fasten in the new fuel tank with 4, 5/16 stainless steel machine screws. The first two which are easiest to access went in just OK. The second two which are significantly harder to reach both "galled" up to the point the nuts could not be moved in either direction.

Had to crawl out of the bilge, down the ladder and over to the shop to grab the sawsall. Then back into the boat to cut the bolts out. Now of course since these are not fasteners I typically use I will need to go back to Hamilton Marine 30 miles away to pick up a new bolt (Probably will replace them all!).

After dealing with the back two bolts I was not super happy with the way the front two machine screws snugged up. So I broke out the bit brace and was able to turn the front nuts an additional two turns or so. From the feel of the bit brace it was obvious that the two front nuts started galling up as they they started taking on some load.

I have dealt with this issue before with stainless and have tried greases, oils, teflon tape and teflon plumbers dope. None of these cured the problem completely but the teflon dope seemed to help the most.

I have had crevice corrosion eat away and destroy the metal under a prop shaft taper on a stainless shaft, dealt with the galling issue before and no matter how much proper bedding and sealing you do with some stainless fittings they leach out iron stains. I have also seen stainless clamps fracture after only a year in service.



I'll take bronze fasters and fittings any day over Stainless but I could not use them on the aluminum fuell tank mounting tabs. I hate stainless!

 

[HiDHo]

Galled threads caused by friction, maybe installed with power tool. I always test thread, any resistance is a warning sign, usually dinged thread.
I find a great selection of 316 stainless fasteners at FastenAll if you have one in your area.

 

[Pack Mule]

Anti -seize is your friend when using stainless bolts and nuts.

 

[KnotYet]

Anti -seize is your friend when using stainless bolts and nuts.

There are even specific anti-seize compounds made for stainless fasteners.

I love 316 stainless.

 

[motion30]

The local stainless steel bolt salesman told me. If you buy 304 screws then use 316 nuts. Said the different alloys will be much less apt to gall each other. This has worked well for me

 

[KnotYet]

The local stainless steel bolt salesman told me. If you buy 304 screws then use 316 nuts. Said the different alloys will be much less apt to gall each other. This has worked well for me

304 will quickly corrode in the marine environment as you may be aware of.

Also, the two alloys are quite similar in appearance and so will be hard to tell apart.

Anti-seize probably should be used even if you mix alloys as you suggest.

 

[Arc]

Tef-Gel the crap out of them. Will never have a problem. Also only had fasten.

 

[Comodave]

Tef-Gel the crap out of them. Will never have a problem. Also only had fasten.

+1 on Tef-gel.

 

[SoWhat]

#2 on tef-gel but any anti-seize will work

 

[Bacchus]

There are even specific anti-seize compounds made for stainless fasteners.

I love 316 stainless.

+1
The other trick that seems to help is to chase the threads with a tap & die to make sure they are good. Lots of off shore hardware that isn't that great.

 

[sean9c]

Use silicon bronze nuts

 

[caltexflanc]

+10 on Tef-Gel. Formulated specifically for this purpose, stainless vs aluminum in particular.

 

[jleonard]

Nylock nuts don't gall either. No anti seize required.

 

[caltexflanc]

Nylock nuts don't gall either. No anti seize required.

A stainless bolt or machine screw in contact with aluminum still needs Tef_Gel or equivalent; the aluminum takes a beating if you don't.

 

[Frosty]

Nylock nuts don't gall either. No anti seize required.

Maybe it's just my bad luck, but I have had a few Nylocs gall. These were 316 from McMaster. If I have to use stainless/stainless, I tighten *very* slowly. (I was never sure if Tefgel and Nylocs would be advisable - should research that.)

I like to use bronze nuts if appropriate to the situation (would like entire bronze fasteners, but not always practical these days). Especially if it's something I may be removing and re-installing.

(For example, I had a swing down all-around light stalk on a radar arch with a 5/16" thumbscrew into a tapped boss on the stainless tubing. So I'd swing that down a few or more times a year. Having the stainless arch boss gall would be a bummer, and it did not need super-strength, so I changed out the stainless thumbscrew for a bronze one. No more worries about galling.)

 

[FF]

WE carry fuel filters , life preservers and fire extinguishers on board , "just in case" and yet we know something on the boat will need repair.

Next time you order from a good marine supply a 1/10 of a boat buck worth of common sizes of bronze nuts and bolts and screws might be a good idea.

 

[Antares]

I agree on using an anti-seize product. I would not use bronze fasteners is the tank is aluminum.

 

[DDW]

Nylock nuts will most definitely gall. I've had them do it just running them down before any tension at all. Anti-seize will work, but Tef-Gel will work much better to keep this from happening.

Bronze is resistant to galling, but Monel is a badly galling material. Using a nut with different hardness than the bolt is helpful, for example Nitronic 60 nuts on K500 Monel, or 17-4PH or Bumax 88 nuts on 316 bolts.

About 100% of SS hardware available in N.A. is now Chinese sourced, and quality varies a great deal but is mostly well below the US or German product of 15 years ago.

 

[Frosty]

I agree on using an anti-seize product. I would not use bronze fasteners is the tank is aluminum.

Sadly, there are times bronze is not a good choice

 

[FF]

"Sadly, there are times bronze is not a good choice."

Yes, then quality galvanized does a great job .

 

[jleonard]

Nylock nuts will most definitely gall. I've had them do it just running them down before any tension at all. Anti-seize will work, but Tef-Gel will work much better to keep this from happening.

I guess I have been lucky then. Never happened to me.

 

[rgano]

Call me lucky - never had the OP's problem.

 

[HiDHo]

I did read about boaters complaining the stainless fasteners they used would show rust marks. Turns out if you use a ferrous metal tool to install the stainless steel fastener it leaves microscopic particles of ferrous metal which cause the rust stains.
I know you can buy non-ferrous phillips bits for your power tools, bronze wrenches are also sold for use in explosive environments but are very pricey.
I don’t know if there is a lube that would keep the ferrous metals from adherence at least in topside areas where rust stains are noticeable.

 

[KnotYet]

I did read about boaters complaining the stainless fasteners they used would show rust marks. Turns out if you use a ferrous metal tool to install the stainless steel fastener it leaves microscopic particles of ferrous metal which cause the rust stains.
I know you can buy non-ferrous phillips bits for your power tools, bronze wrenches are also sold for use in explosive environments but are very pricey.
I don’t know if there is a lube that would keep the ferrous metals from adherence at least in topside areas where rust stains are noticeable.

Instead of stocking non-ferrous tools you can 'passivate' the stainless fastener
with a mild acid and a toothbrush.

 

[bayview]

Ace hardware often stocks SS

 

[Steve DAntonio]

While TefGel and anti-seize will work, virtually any lubricant will prevent stainless steel galling, including ordinary oil. Anti-seize should be used with caution for two reasons, one, most are metallically loaded and in some cases that metal is copper, which you would not want to use with aluminum substrates (aluminum is anodic to all metals except zinc and magnesium). Two, you don't want to use it on fasteners that are cyclically loaded, like motor mounts and coupling bolts, as they will tend to loosen. This article covers galling in general and for prop nuts specifically (ideally, prop nuts should be manganese bronze) https://stevedmarineconsulting.com/propeller-installation/

 

[sdowney717]

Have not had SS gall if it is greased. The few times some SS small bolts on nuts galled on me they were fine thread and I tightened them dry. So try to avoid fine thread is what I do and a little marine grease on the bolt.

 

[thirsty boy]

Always put SS together with anti-seize. There are different brands but if it says thread sealant and lubricant, it will work. As far as corrosion, SS that is wet and in the absence of air will corrode.

 

[Brooksie]

316: well worth the slight extra $.

Bolt Depot : reasonable quantities & prices. Family owned, American made stuff.
Never-Seize or equal: Good for everything threaded.

 

[BrianSmith]

316: well worth the slight extra $.

Bolt Depot : reasonable quantities & prices. Family owned, American made stuff.
Never-Seize or equal: Good for everything threaded.

+1 for Bolt Depot. They have EVERYTHING!