Stainless Steel Question

Here’s another question for who ever, As many of you know by now I make most of all my own housings. Again I’ve run Into a question you might be able to help me with. I’m making my

own push button type controls for my up coming housing ( Fuji S2 Pro ) I have figured out the

design, and have built a prototype and tested it to a depth of 179 ft. The finished product will

actually go deeper than this. My problem is with the quality of the springs that I will be purchasing. It seems most of the Spring manufacturing companies want to sell me a Stainless steel spring that I have know experience with. I’ve mainly used Type 303 stainless steel.

I have never had any trouble with it, such as rusting. Most of the manufactures want to sell me Type 302 springs that they have in stock.. I did receive sample springs and their perfect for my application. My confusion is with getting different opinions from sale persons. Some say it is, and will work fine, and should not rust. Others say I should stay away and use a higher quality. The samples I received are slightly magnetic, which Leads me to the feeling they probably will rust. I know there are better qualities of stainless but they’ll cost me 10 times the cost. They’ll be custom fabricated to my specifications, and I’ll have to buy 100's more than I’ll ever use.

Does anyone think I could use type 302 for my springs?

How about you Ike, if anyone knows I'm shure you do?

Unfortunately, I think that crevice corrosion will be more of an issue with 302 than with the 303 series. If you can make sure that the spring can be rinsed thoroughly and not sit with NaCl on it then you should be OK. Your magnetic measurements have much more to do with how the material is formed than with the actual composition. If I remember correctly (it was a long time ago) you can remove the magnetism by annealing.

It sound like you know what your talking about.

It’s definitely a problem as to how I ‘m going to flush out the controls after every dive. Salt X

is most useful with a good soak, while working the controls in and out. A friend recommended

replacing the springs with a maintenance plan. I would like to make it as maintenance free as possible.

Is there is a process like anodizing, but for Stainless that would help ?

Thanks for the input,

Marc

Salt X strikes terror in our heart because it can cause many plastics to craze or crack just like spray lubricants which should never be used around plastic.

Salt X strikes terror in our heart because it can cause many plastics to craze or crack just like spray lubricants which should never be used around plastic.

Hi Ike,

Thanks for saving me the the trouble of learning the hardway. I've never used it

besides cleaning my boats motor.

By the way, I got a very nice response from Blake at Aquatica, He's recommending I have my springs Zinc plated.

Have you ever used Type 302, or do you use a higher grade of Stainless ?

Thanks Again to both of you for your support here at Wet Pixel.

Happy 4th,

Marc

You will find that most "stainless steel" springs are not actually SS. Unless a specific alloy is called out it usually only meets a spec for corrosion resistance. It is difficult to get the elastic qualities out of SS and you have to pay for it. The spring metals that will attract a magnet are not normally SS but offer some degree of corrosion resistance. I can offer more assitance when I get to work tomorrow. I am an engineer. I have some supplier that can answer that question if they work on the 5th.

Krash,

I would appreciate any information you could assist me with.

Thanks so much for your support.

Marc

hi Marc,

I'm not a metallurgist, but after looking through some materials, it appears that 302 and 303 are very similar metals. This reference appears useful:

http://www.kastenmarine.com/mbqMetRef.pdf

Mike

Industrial Spring Corp.

(816) 741-6073

They are not in today (5th). They may be able to answer your questions.

If possible, 316 stainless is pretty good in most appliacations. Plating in our hands (medical devices for long term i.e. 10 years implants) just doesn't work. Any pinhole makes the problem much worse.

Bill

I finally resolve my stainless steel issue.

I have contracted with a spring manufacturing company. The springs will be fabricate exactly to my specification, and be made from stainless steel type 316.

Thanks for all your support,

Marc

I am curious - do you mind posting what you have learned? I am in the food service industry so we work with stainless steel sheet metal daily. I am interested to hear your conclusions even though I do not deal with salt water applications.

Hi Krash,

I don’t think I’m going to be able to teach you anything you probably don’t already know.

My experience has been with recommendation from manufactures trying to sell me their products .I have done some testing on a sample spring made from type 302 S/S. I have repetitiously place my sample in sea water for hours, and days at a time. With out any success

in it’s change in appearance. I guess that’s good if my testing has any validity to it.

My objectives were to be able to afford the best material at a reasonable price. I think I have

achieved my goals. I have a manufacture making my springs at what I believe is excellent price.

It actually costing me .19 cents for each spring made from type 316 S/S. Which everyone in the spring business agrees will be most adequate for my application. Of course I’m buying 1000

springs , about 985 more than I’ll be using on my S2 Pro housing. That will leave me with some extra spring in case I disced to make a few extra housing available for sale later.

I did do some follow up on a suggestion on Zinc plating. Most manufactures agree that it would

not hold up to repeated compression cycles and was to costly verses a higher grade alloy .

Thanks again,

Marc

How much trouble is it for you to replace your springs? I would consider the zinc only if you are able to change them out after a dive trip.

I use an ASTM test for EN plating that may prove useful to you. Basically, you boil salt water (table salt not sea water). Use a SCUBA tank (clean compressed air) to aerate the water. I leave the parts in the water for 30 mins. The plating is on steel and will show rust if there are any holes. You could cycle this test many times for an aging test. Each cycle would certainly be more corrosive than a dive.

Plus you have an alternative use for the SCUBA tank you paid $150 for and don't travel with!