304 or 316 tubing?

[stove]

I am refurbishing my pushpit and some stanchions and was wondering which stainless steel is generally used 304 or 316.

[BillKny]

304 will gradually collect surface rust, 316 will not. 316 can corrode at the welds, the lower carbon alloy 316L is much better for this issue.

Basically the only reason to use 304 is that 316 is too expensive for your pocketbook.

[pcmm]

Originally Posted by BillKny

304 will gradually collect surface rust, 316 will not. 316 can corrode at the welds, the lower carbon alloy 316L is much better for this issue.

Basically the only reason to use 304 is that 316 is too expensive for your pocketbook.

Or unavailable. Where I am on the great lakes 316L is almost impossible to find without doing a special order or full length pieces I.E 20ft lengths

[stove]

Thanks for the info about 316L. It's as I thought, the pocket book determines the material.

[Jim Cate]

IMO the long term advantage of 316 (much less polishing to keep shiny) is worth some additional cost. And would a 20 foot length have all that much left over? Depends on design of pulpit, I guess, but mine would have nearly that much in it.

Jim

[Orion Jim]

If you just need a short length of 316 buy a piece from a marine canvas shop or a marine fabricator. They always have left overs which they hope to find a need for at some point.

[boatpoker]

Originally Posted by pcmm

Or unavailable. Where I am on the great lakes 316L is almost impossible to find without doing a special order or full length pieces I.E 20ft lengths

Over the last 3yrs in Toronto I have bought various lengths from 6' to 12' for stanchions, solar panel mounts, bimini and dinghy mounting rails in Toronto (1hr from Whitby) without any problem whatsoever.

[Pelagic]

If you Polish the 304 to a high finish, it takes care of rust issues

[boatpoker]

Originally Posted by Pelagic

If you Polish the 304 to a high finish, it takes care of rust issues

and hit it with a coat of Barkeepers Friend

[pcmm]

Originally Posted by boatpoker

Over the last 3yrs in Toronto I have bought various lengths from 6' to 12' for stanchions, solar panel mounts, bimini and dinghy mounting rails in Toronto (1hr from Whitby) without any problem whatsoever.

if you know places I'd be open to ideas, I'f found that buying ( or trying to buy 316) in Toronto most of the metal shops I've asked ( when really pressed didn't actually know if what they had was 304 or 316.

[Dave_S]

Most producers of SS have a colour coding for the grades, here red is 316 and yellow is 304, painted on the ends, it is probably different there but you should be able to find out.

I would still use 316.

Good 316 used to be great stuff, most is chineesium grade SS now and is made in it's lowest form to satisfy a standard, so, depends on the standard. Almost all 304 and 316 will tea stain now. It used to be 303 (machine grade) and below would do that.

Use a pickling solution (from welding shops) on welds, works a treat. It's nasty stuff so wear the PPE when using it. It sorts out the discolouration and corrosion.

[Manateeman]

Find a welding shop and bring some nice cold beer. Ask them to please explain why they flood the interior of stainless with argon before TIG welding.
You will also learn a lot about stainless from anyone who fabricates pipes for food processing or pharmaceuticals.
My manatee crew TIG welds custom stuff for a brewery for free beer.
Happy trails to you .
Mark and his crew

[Dave_S]

Never clean it with steel wool or a steel buff, or for that matter anything that has been used to clean or polish steel. It will impart the steel to the stainless and rust.

[s/v Jedi]

A highly (electro) polished 304 will stain less than a poorly polished 316. I have some 304 tubing from West Marine that is 15 years old and spotless with less maintenance than some 316 I have.

[Pelagic]

Exactly Jedi
I have a 2" 304 flat bar that was welded as a T-section on rub rail so they could clamp the teak timber as final rub rail.

Needing replacement, as a test, I had the 304 highly polished with compounds.
Looked great, so forgot about finding the teak and faired so that rain decants into sea without touching hull.
14 years later it still looks perfect with a light hand Polish once a year