[PSUBS-MAILIST] 302 v 316 stainless for springs

Wed Oct 1 10:32:22 EDT 2025

Hi James, 

Bit late reply but SS316 is likely to soft for springs. 316 has a yield strength of 250 N/mm2 and spring steel 1500 N/mm2

Br, Emile

Van: Personal_Submersibles <personal_submersibles-bounces at psubs.org> Namens James Frankland via Personal_Submersibles
Verzonden: woensdag 1 oktober 2025 13:16
Aan: Personal Submersibles General Discussion <personal_submersibles at psubs.org>
Onderwerp: Re: [PSUBS-MAILIST] 302 v 316 stainless for springs

Hi both.
Thanks for the advice.  I am still awaiting final quotes, but I suspect i may well go for 302.   316 is very expensive.

I will probably cover the springs in laquear.   Someone gave me my K350 springs.  It was a guy in USA.  So they could well be 302 and ive never had any issues with them.  They are laquered.

Regards
James

On Tue, 30 Sept 2025 at 19:59, Rick Patton via Personal_Submersibles <personal_submersibles at psubs.org <mailto:personal_submersibles at psubs.org> > wrote:

Hey James, I think you'll be fine with that grade as long as you wash it well after every dive. It will haze like some other grades above it but the haze is only on the surface unless it was never washed but for the cost of the 316-L, I would think that 302 is OK. If the haze gets really bad, you could pickle them but would have to take them off of course for that. 

Rick 

On Tue, Sep 30, 2025 at 3:13 AM Cliff Redus via Personal_Submersibles <personal_submersibles at psubs.org <mailto:personal_submersibles at psubs.org> > wrote:

James, your dive environment is different from most psubbers, being exclusively salt water.  I don't have any experience with using 302 stainless steel for hatch springs, but for both the R300 and R400, I use spring-tempered steel wire, ASTM A229, that I have power-coated.  This has not been an issue for the 10 years I have been operating the R300.  Yes, 316 stainless would be the ideal case but given that we don't put these in the water that often and always rinse them off after dives, I would not have a problem with using 302 SS.  While 302 stainless steel is prone to pitting in saltwater, the consequences of failure are low.  If pitting occurs to the point that the spring breaks, you lose some support against the weight of the hatch.  This is not a big deal. It is not worth spending excessively on the 316SS for this application.

Best

Cliff

On Tuesday, September 30, 2025 at 07:39:00 AM CDT, James Frankland via Personal_Submersibles <personal_submersibles at psubs.org <mailto:personal_submersibles at psubs.org> > wrote: 

Hi All

Im struggling to get hatch springs made at a decent price.

Has anyone used 302 stainless in a salt water environment.  I know its not the right material, and not supposed to be used in salt water, but they are so much cheaper and readily available.

I could possibly coat them in some sort of lacquer or even just replace them every dive. They really are that much cheaper.

Im still trying to get 316.

Anyone used 302 springs in the sea?  Did they disintegrate?  

Regards

James

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