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Replacing hardware; Stainless - Titanium... pros - any cons
Topic Started: Jun 4 2014, 01:17 PM (757 Views)
brsja
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Thought I'd start a new discussion.
Topic is replacing the stock hardware with what many would thing is better hardware, I'm talking Stainless - Titanium for the most part, but there are others as well.

Not an expert on hardware, so the question I have is it always ok to replace old rusty bolts and screws with new shinny stainless (SS) or titanium??? IDK

I have read on a few thread SS may not be as strong in some aspects. I also know from aviation about dissimilar metal corrosion. It's a big deal on airplanes, for example you can not put aluminum in contact with titanium, they are not electrically compatible and the aluminum will turn to dust in a few years or so, especially if it gets moist.

So hardware and engineering experts, what about it. Can we say one can always replace a stock steel bolt or screw with a certain grade SS.

Let the fun begin ^o)
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Bjetmech
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Outside of aviation I have never seen a titanium fastener. Very expensive. And if not heat treated right it can be very brittle. The only advantage to use Ti is for weight and there aren't enough fasteners to gain that much to make it worth the cost.

I think stainless would be the way to go. Still a bit expensive but cheaper than Ti.
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doviatt
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Zinc plating is also a reasonable rust prevention coating that comes on a lot of hardware. Try to know the manufacturing source of the HW. Plastic boxes with assorted sized HW from a department store can be of poor quality and unknown origin. Try for industrial quality that will test quality to ANSI or similar standards.
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Old Man


zinc plates are used on ships to stop electrolysis from eroding the ships hull. The zinc sacrifices and erodes away instead of the hull.

Knowing this, I would be very reluctant to use zinc plated hardware in any application where electrolysis can/will occur.

My preferred choice is Stainless Steel. Any 300 series Stainless. Stay away from the 400 series Stainless because it contains carbon and will rust almost as bad as stock hardware.
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t3ragtop
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Turbo3 and Twincam Tweaker

316 stainless is a marine grade material that takes a sparkling polish.

knowing what grade hardware you are replacing is the key. if it's just a general fastener, a2 stainless is okay. if it's a load bearing fastener like a suspension bolt use something with a similar rating, 10.9 or 12.9 (grade 8 or better.)

i have used 17-4 stainless in special places, like head studs. i have also used titanium bolts is a few key spots like the accessory pulley on the crankshaft - even with a lightened aluminum pulley. the key there is to use anodized aluminum and anodized titanium fasteners together. also, always use never seize on ss and titanium bolts. those alloys gall very easily and can permanently lock up without lubrication.

i've searched out special cheesehead screws to replace the buttonhead oem screws they used on bumpers, dash and interior panels. i use flange nuts, flange shoulder bolts, buttonhead allens - all kinds of neat fasteners.

i live in the rust belt and even on my summer cars, the ones that never see salt, zinc plated fasteners turn into rust balls in a matter of a couple years. my father in law drove his 2 year old van on a western vacation, had a flat tire and some suspension damage and had to have a service station in oregon work on it. the mechanic said that he had never seen a car that was so rusty on the bottom! 2 year old gm machine!

my red vert had almost every bolt on it rusted into it's threads, and so bad that most of them just broke off even with heat, good penetrating oil, and care taken while trying to get them loose. i have almost every bolt replaced with stainless and it doesn't bother me to take something apart now. ;)
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myredvert
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myredvert

I'm not about to provide fastener advice when we have t3 and others to share some serious knowledge that I don;t have, but I do have one quick comment about titanium that I learned from exposure to aircraft design and modification projects...

Quote:
 
The only advantage to use Ti is for weight
In addition to "saving weight," titanium fasteners can be used for higher strength than conventional to be achieved for the same weight, titanium has I believe decent high temperature performance (good enough for the 600 degree or so external skin temps on an SR-71, but not good enough for use in exhaust gas paths like inconel is), and performs well at extreme low temperature.
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punkozuna
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What most people don't understand about titanium is that the strength to weight ratio is similar to steel (and aluminum). It's lighter than steel per unit volume but heavier than aluminum. So in applications where you need high strength in small volumes (like fasteners) steel is better. In applications where you need high volume and low weight (like motorcycle spar type frames), aluminum is better. Titanium is great for higher temps than steel or aluminum, has better corrosion resistance than steel. Titanium exhaust pipes for motorcycles are available (but expensive) because they are lighter than steel and can withstand the exhaust temps without rusting out. If aluminum pipes could take the vibration and heat, they'd use them instead.
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brsja
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So what about oil pan bolts, anyone use stainless steel?
If so where did you get them?
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Old Man


In my little town there is an Ace Hardware that has individual bins in a section about 20 ft X 5 ft of nothing but MM stainless bolts, nuts and washers.
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t3ragtop
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Turbo3 and Twincam Tweaker

oil pans have m6 x 1.0 screws 10mm in length. the front corners have studs in the same thread size and 15mm long capped with flange nuts.

all that business is available in a2 polished stainless steel.

i use 12mm long allen head cap screws with small flat washers and split washers in stainless on my oil pans. ;)
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t3ragtop
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Turbo3 and Twincam Tweaker

punkozuna, you use titanium where you want a weight savings over steel and higher tensile strength than aluminum.

i use titanium some places "just because i can." :D

i worked under contract with nasa on the space shuttle and a lot of times i just like the fact that i can use aerospace materials on my car. :)

going back about 10 years, i had a friend who ran a mail order store for custom suzuki swift parts. he sent me a prototype titanium keeper plate for the ends of the transmission shafts behind the 5th gears. i'm holding it in my hand right now. it's probably the only one left in the world.

it's so rare that i have never been able to bring myself to install it. :P if i did, nobody would ever see it.

i'm running titanium bolts to hold the aluminum accessory pulleys to the cranks on 3 engines and nobody ever sees those. i also run adjustable aluminum cam sprockets on my 2 turbo3 engines and i used titanium bolts in those. i bought titanium m6 shoulder bolts for an aluminum water pump pulley before the pulleys were even made. :P

see, i just do it because when i worked on the shuttle i couldn't afford titanium hardware and now i can buy the stuff. i do it just because i can. ;)
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Coche Blanco
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t3ragtop
Jun 11 2014, 11:32 PM
punkozuna, you use titanium where you want a weight savings over steel and higher tensile strength than aluminum.

i use titanium some places "just because i can." :D

i worked under contract with nasa on the space shuttle and a lot of times i just like the fact that i can use aerospace materials on my car. :)

going back about 10 years, i had a friend who ran a mail order store for custom suzuki swift parts. he sent me a prototype titanium keeper plate for the ends of the transmission shafts behind the 5th gears. i'm holding it in my hand right now. it's probably the only one left in the world.

it's so rare that i have never been able to bring myself to install it. :P if i did, nobody would ever see it.

i'm running titanium bolts to hold the aluminum accessory pulleys to the cranks on 3 engines and nobody ever sees those. i also run adjustable aluminum cam sprockets on my 2 turbo3 engines and i used titanium bolts in those. i bought titanium m6 shoulder bolts for an aluminum water pump pulley before the pulleys were even made. :P

see, i just do it because when i worked on the shuttle i couldn't afford titanium hardware and now i can buy the stuff. i do it just because i can. ;)
And unlike the shuttle, your Metro lives on...


(the plate you speak of, is that the one with the 6 screw holes and the 2 big holes?)
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doviatt
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Not true. The shuttle lives on (museum worthy) and has way more miles than probably any car. It was just decommissioned as it met its projected life requirement (or lack of budget to fly it any more).
Edited by doviatt, Jun 12 2014, 12:55 AM.
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Coche Blanco
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doviatt
Jun 12 2014, 12:54 AM
Not true. The shuttle lives on (museum worthy) and has way more miles than probably any car. It was just decommissioned as it met its projected life requirement (or lack of budget to fly it any more).
The shuttle is not living. What I said was true, move along.


(yes I'm a fan of NASA, no they don't get enough funding, Obama sucks)
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Way


In my experience delivering parts to garages, I found that the majority of garages used anti-seize lube more so than stainless bolts / nuts. This was a while ago but they seemed to swear by it more than swear at it.

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