No problem, hope this comes together for you. We did quite a bit of what we called "Rust Check" on stainless parts as well as other parts. We placed them in a tank of pure deionized water running oxygen bubbles in the water. The water was maintained at 190 Deg. F. After prescribed times the parts were removed and inspected using magnification. The idea or thinking was the stainless parts, mostly 317 stainless wouldn't rust but tiny pin head spots of rust would be found. That was steel left embedded from any machining process. Back in the tank after cleaning again and again till the parts passed ruct check inspection. Wasn't my thing but I watched it daily.

Good luck in finding an alloy.

Ron

 

When I dismantled a 30-year old electric shower and a vintage steam iron (as you do ) a while back I found springs which looked as though they were made of brass, or perhaps phosphor-bronze? Their immersion had caused some discolouring but no other sign of corrosion.

 

When I dismantled a 30-year old electric shower and a vintage steam iron (as you do ) a while back I found springs which looked as though they were made of brass, or perhaps phosphor-bronze? Their immersion had caused some discolouring but no other sign of corrosion.

I did consider phosphor-bronze for my application. The problem is that said alloy has trace amounts of lead in it. And this application is for a special domestic valve through which drinking water will be running.

 

Well, it seems that I'm going to have to use two springs for this project. One is an extension spring made of 0.020 mm 316 wire, which I've already shown pictures of in previous posts. And the other one will be a double torsion spring made from either 0.035" or 0.049" (#18 or #20 ga) wire.

I've already received quotes from several suppliers, and I must say that pricing for samples has been consistently outrageous. While volume pricing is fairly decent and expected (in quantities of 5,000 and above), the minimum number of samples they're willing to sell is 20, at $23.00 bucks each!

So I've decided that if I'm going to spend close to $500.00 on samples, I'll better get them right the first time. That is, I'll better make sure that my design is 100% effective. So what I'm going to do is buy from a local supplier 5Kg of each of the two wire gauges I intend to test, and then make those springs by hand myself. That material will end up costing me a total about $250.00 dlls. But that way it won't matter if it takes me a couple of day's work to get it right... nor if I make dozens of springs that don't perform as I want them to. I'll have enough material with me to experiment to my hearts' desire...

Of course, I'm going to have to fabricate some sort of gig or fixture to help me make those torsion springs, but that's something I've already thought of and I'm sure I can come up with something workable... at least to make those much needed few samples.

 

Do they have any 316 springs that are similar you can get as samples? It might help you to have something to test against. With 316L the material work hardens quickly so it shouldn’t be difficult to get a spring just by forming it around a mandrel. You will have to design the mandrel to what you need. You might be fine with found objects... even a drill bit Might work.

 

Do they have any 316 springs that are similar you can get as samples? It might help you to have something to test against. With 316L the material work hardens quickly so it shouldn’t be difficult to get a spring just by forming it around a mandrel. You will have to design the mandrel to what you need. You might be fine with found objects... even a drill bit Might work.

Yeap, I've already experimented with drill bits before, and they work alright. I do have a few samples with me of springs of a similar size to what I need also made of 316L, although they're of the single coil type. Making the double torsion spring that I need by hand is going to be a little tricky, but I'm sure I'll find a way to make it work somehow.

But rest assured, I have no intention of manufacturing this things myself. I plan on outsourcing them from the best bidder once I've made and thoroughly tested the perfect spring and carefully annotated its specs.

 

For prototype work would they need to be SS? It will take a long, long time to really degrade even a bare steel spring in water. And many are lacquered not bare.

 

For prototype work would they need to be SS? It will take a long, long time to really degrade even a bare steel spring in water. And many are lacquered not bare.

Good point. But I prefer to make them from the material they're supposed to be from the start. Mainly because the elastic and fatigue properties are slightly different between ordinary music wire and hardened ss wire.

I'd rather learn from the start about any potential problems that might arise during use.

 

Good point. But I prefer to make them from the material they're supposed to be from the start. Mainly because the elastic and fatigue properties are slightly different between ordinary music wire and hardened ss wire.

I'd rather learn from the start about any potential problems that might arise during use.

But doing it with music wire, off the shelf springs would get you an empirical figure to the strength of them cheaper and faster.

 

But doing it with music wire, off the shelf springs would get you an empirical figure to the strength of them cheaper and faster.

I've also considered that... and I've also already played with a lot of surplus springs from local suppliers. That way I've been able to estimate a very good approximation of what I want. And of course, I've also done some calculations. That's how I arrived at the conclusion that either of two different wire diameters are going to get me the results I want.

And another thing is that local and foreign suppliers are giving me more than a week of delivery time per ordered sample. That's why I think it's crucial for me to do this testing phase in-house.... time has become a critical commodity...