PDA

View Full Version : 316 vs 304 Stainless Steel. How critical a difference?



Toyon
12-Oct-2007, 09:21
Is it a bad idea to buy a darkroom sink made with 304 stainless, versus the more frequently recommended 316 stainless? I use only black and white chemistry.

Colin Graham
12-Oct-2007, 09:29
304 is not recommended for saltwater contact, but other than that it's the most commonly used stainless steel. Other than being marine grade, 316 is stronger too. I imagine the price difference would be quite a bit.

John Schneider
12-Oct-2007, 09:31
To be pedantic, a 304L sink with 309 filler rod would be the best material. Unless you plan submit the sink to large tensile stresses or to immerse the sink in concentrated salt solutions at elevated temperatures, 304 will be fine. For room temperature aqueous solutions of moderate pH, 304L is preferred, which is why it's used for all food-grade applications.

resummerfield
12-Oct-2007, 09:39
My sink is 316L and the back splash is 304L. They have been in use many years and subjected to the same conditions, and there is no visible difference. The 304 should work fine.

vann webb
12-Oct-2007, 09:57
304 is fine. We build food grade washdown st. st. machinery at the company that I work at, and it holds up for years and years. 316L is really only necessary in the most demanding circumstances, and it is quite a bit more expensive.

neil poulsen
12-Oct-2007, 09:59
I wonder if it matters whether or not color, either film or paper, is being done in a 304 vs. a 316 stainless steel sink.

Of course, people aren't really doing as much color processing these days.

Randy H
14-Oct-2007, 03:28
You are just doing photo work. Get whatever is the cheapest in your area.
If rocket-science is what you are after, get inconel. Or monel, at least.
Your precious prints and negs could care less if it was plastic. Some of the finest prints ever made came off a plywood table covered in fiberglass. Geez. Put the serious money where it seriously belongs.

Jay W
16-Oct-2007, 05:38
I had two four ft stainless steel sinks made a number of years ago, and didn't know there were different types of stainless steel. (I was young and stupid.) The sinks rusted, particularly near the drains. I don't recall if the drains rusted, but I think they did. I remember hearing that chlorides can cause rusting problems unless you specify the correst SS for the job. In spite of that, I now use one of the two sinks without a drain and occasionally sand it to get rid of the rust. (I'm just using it for film developing, and there's no sewer connection nearby.) I've wondered if I could shine the thing up and then coat it with a clear finish like a polyurathane. Ideas welcome.

I kind of agree that a sink could easily be made to look good, that would be cheaper and easier to build without using stainless. Down the road if you move houses or switch to digital (slap me), you could just trash the sink. It's hard to scape a SS sink because of the money invested.

Jay

Bruce Watson
16-Oct-2007, 06:05
Is it a bad idea to buy a darkroom sink made with 304 stainless, versus the more frequently recommended 316 stainless? I use only black and white chemistry.

Some color chemicals will supposedly etch 304 and not 316. If you are ever going to do color work, you should probably go ahead and use 316. If you use 304, you are essentially closing off your options.

Randy H
16-Oct-2007, 08:14
I have worked with stainless, monels and inconels and chromes for a living for 30+ years. Unless there is a very specific requirement for one type, why bother with the cost, weight, etc. ALL stainless "WILL" develop surface rust if subjected to moisture "of any kind". We use high-grade 316L, and if left outside in the elements, will develop a surface rust in about a months time. Scotch-brite it, and forget it. Hospital-grade 316 sheet will rust if left unattended. Commercial food-grade 316 will rust if left unattended. If you are doing color work, and have the bucks to help buy the salesmans Lexus, go for the Lab-grade 316L. Otherwise, build your sink in the size and shape you want with plywood, and cover it with fiberglass resin. Seems the major proponents of "gotta be 316+ blah blah" are the ones that have helped buy the Lexus.
The work we do is from hospital equip to food-grade to corrosive chemical pumping systems. I am needing to make my next house payment. I have a few sheets of 316 commercial-grade stainless out in the garage. Wanna make a deal?