Seriously off topic

[smittys800]

As the title say, VERY off topic, but need help anyway.
I use Stainless Steel Bolts in these products that I make, and choose Stainless Steel since they are in the Elements ALL the time. Have had a few concerns with stripping the bolts/nuts and on occasion, broken bolt.
The grade of Stainless I get is A-2 ( 18-8 )
I personally have had no problems with them. They are used in Suspension brackets for sleds ( Snowmobiles ) I use Metric Socket bolts, washers and Nylocks.
Was hoping I might find a supplier for the GOLD color'd corrosion plating.
Any ideas, and sorry for the off topic, just ran out of luck with searching the net!
Smitty

[Donkey Hotey]

What are they in contact with? I hope it's not aluminum. You know about galvanic corrosion, right? Stainless and aluminum is just about the worst combination possible.

Stainless to stainless will gall. Stainless to many other materials is a very good battery. As favorable a material as it might seem, it's often a poor compromise.

This is often why products use plated steel when stainless fasteners seem like such an obvious choice. In something that is high load (suspension parts), high grade steel is probably the better choice.

[smittys800]

It just so happens to be Aluminum!!!
Hmmm,
Better re-think this quick!

[Donkey Hotey]

Do a search for Galvanic Corrosion or Galvanic Scale. Think about it: what is a battery? Two dissimilar metals with an electrolyte (water can be enough). The further apart the two metals are on the Galvanic Scale, the more voltage you get. Lead acid batteries work on the the same principal as corrosion. This is also why aluminum manifolds and heads destroy themselves in contact with a cast iron engine block. We never had these problems in the 'old days'.

That's the powdery, white substance you get in a joint bolted with aluminum and stainless. This kind of stuff gets done all the time in aircraft but you have to take precautions. Wet installing fasteners with an appropriate sealant for example. It's not generally a good idea in something like a consumer product.

Of course: your customers might not know that and even though it's a poor choice, they might be happier if the hardware is stainless. Perceived quality is often worth more than actual quality. Sometimes it's more about the marketing.

[DSL PWR]

The gold color is cadnium plating. You can get gold or clear/silver cad plating.

What sled do you market parts for? I run an 04 Summit X 151. Do you have a web site?

[smittys800]

DSL PWR,
Just E-mailed my supplier about a possable return, as I have a TON of Stainless.
As a matter of fact, most of my parts are made for the REV Chassis... the drop brackets work awesome in the deep!!
The web site is a work in progress....
smittysspeedworks.com

[Mike Stevenson]

Titanium bolts would be sublime.

[JoBwan]

Stainless and aluminum is just about the worst combination possible.

Donkey,
I am by "no" means a metalurgist, but what about galvanized fasteners?

[Donkey Hotey]

It just depends on where the metal combination is on the galvanic scale. Stainless-aluminum: aluminum loses. Zinc-aluminum: zinc loses.

That's why they have galvanized fasteners (zinc coating). That's why outboard motors have a sacrificial anode made of zinc or magnesium bolted to them somewhere. Aluminum hulls usually have a larger block bolted somewhere.

Water heaters have a zinc anode rod to prevent this from happening. After five years or so, the zinc is all gone. The process starts attacking the steel tank and your water heater rusts out.

Marine engines and most larger, commercial diesel engines have zinc anodes screwed into the engine block (cooling system). Passenger cars rarely last 30 years so they don't care but diesels are often in service for a long time. The anodes protect all the dissimilar metals in the cooling system.

It might sound complicated but all you have to do is Google for Galvanic Scale. Basically: the further two metals are apart on the scale, the worse they will be together. The one higher on the scale wins--meaning the lesser metal will be consumed in the corrosion process.

[PBMW]

In Smitty's case though, They spend little time in the wet. Most live in the garage during the week and only see one or two days a week in the snow. I have seen stainless fastners used on motorcycles for years. Very little corrosion.

[Donkey Hotey]

I agree...and disagree. I'm a motorcycle guy too, so it's sort of the same thing. The biggest enemy in my case is washing the bike. You take it out, wash it up really good, soap everywhere, a little degreaser...you know. The water seeps into joints, engine covers (just around the fasteners), brake calipers, etc.

When you're done, it get's lovingly dried, waxed and polished. The problem is that you don't go out and ride it (which would heat everything up and dry it out). You park it. And that water stays trapped in all of those joints.

I've pulled axles where they were totally chalk-white from corrosion. It was from being too good to the bike. The water doesn't have to get into the bearings. Motorcycles have plated steel axles, going into steel bearings--sometimes with brass spacers or other hardware--and clamped into aluminum fork legs. Water definitely seeps into those joints unless the assembly surfaces are well greased.

I can imagine that snowmobiles are the same way. They get used in a wet environment, come home just a little damp, then get put away. The moisture condenses in the joints and the damage is done.

The real challenge for a manufacturer of products is guessing how the end-user is going to use the item. If I know that the joint is never going to remain damp, stainless against polished aluminum is really pretty (I'm guilty of having done this very recently on some tooling I made). If I don't know, then I have to plan for the worst.

And as I posted before, it may not matter. A 'polisher' guy is going to want shiny, stainless hardware, even if you spend hours telling him why it's a bad idea. I'm guilty here too.

[PBMW]

Yea, I know. I have a bunch of British bikes. Some have plated fastners, I've put stainless fastners on one of my Nortons, No issues. They are inside, not in the rain, when I wash them, they get heat cycles and blown off. the axels are greased, yada yada. A lot of these guys now a days only keep a sled or sport bike for a year or two. Then it's on the the next fad.