Over 698,000 strictly plumbing related posts
Plumbing education, information, advice, help and suggestions are provided by some of the most experienced plumbers who wish to "give back" to society. Since 1996 we have been the best online (strictly) PLUMBING advice site. If you have questions about plumbing, toilets, sinks, faucets, drains, sewers, water filters, venting, water heating, showers, pumps, and other strictly PLUMBING related issues then you've come to the right place. Please refrain from asking or discussing legal questions, or pricing, or where to purchase products, or any business issues, or for contractor referrals, or any other questions or issues not specifically related to plumbing. Keep all posts positive and absolutely no advertising. Our site is completely free, without ads or pop-ups and we don't tract you. We absolutely do not sell your personal information. We are made possible by:
Author:
nicholas123 (FL)
Does anybody see any problems with using stainless steel drop elbows like the one below?
I found some that cost much less than brass and I like the additional drop ear which should make it more secure.
I plan to use brass nipples and brass angle stops with these stainless steel drop elbows.
My real concern is with galvanic corrosion, but others on this site have mentioned that stainless thermometers are routinely screwed into brass fittings with no problems.
I also saw a great price on stainless steel nipples, but HJ mentioned the galling problem, so I will skip on those. Besides I will have the brass angle stops, so I will still have the stainless/brass issue.
I've done a lot of research on galvanic corrosion and it has so many variables so there is no clear answer from reading alone. That's why I was hoping someone would have some real-world experience to offer on this issue. I live in South Florida so my water is hard with calcium and the pH is around 8. You can taste and see the calcium in the water sometimes. In addition, my city-supplied water smells like chlorine sometimes.
The copper pipes in my neighborhood don't last long so I am converting to cpvc, that's why the drop elbow has a cpvc socket. I know the brass nipples are similar to copper so whatever is attacking my copper pipes will probably attack the brass nipples as well, but at least the nipples have much thicker walls. Any advice, especially first-hand experience on stainless/brass corrosion would be greatly appreciated!
|
Post Reply
|
Author:
KCRoto (MO)
Hard water doesn't tend to harm copper tubing without other factors in play, but if you are replacing it, Pex is a much smarter option. Pex can be installed without as many fittings and is more durable than cpvc. Plastic fittings won't corrode and can be used in both acidic and alkaline situations. Pex can be bent around and contorted while installing provided that you don't kink it (Uphonor is different) to accommodate installs from attics or crawlspaces. Brass fittings don't generally corrode badly no matter what pipe type is installed into them.
|
Post Reply
|
Author:
hj (AZ)
Brass and copper are two different materials so problems with one do not affect the other.
|
Post Reply
|
Author:
KCRoto (MO)
[www.copper.org]
This chart has the chart of "Standard Galvanic Series Of Common Metals In Sea Water
(Ranked from most corrodible to least corrodible)"
The farther away on the chart that two metals are, the more reactive they are with one another. The article is describing fire systems, but it doesn't change the chemistry any. The article is a good read if you have 5 free minutes or so.
|
Post Reply
|
Author:
nicholas123 (FL)
Thanks for the article, KC. I think I read it a long time ago, but I read it again. It has some good information. Unfortunately, it talks about copper/steel and not brass/stainless.
I am no expert. The more I dig the more I find I don't know. For example, stainless steel can be either more or less reactive than brass depending on whether the stainless has a thin protective film which depends on adequate oxygen. If there is little oxygen, the stainless corrodes and the brass is safe. If there is adequate oxygen, the brass corrodes and the stainless is safe. That is why the stainless steels are listed twice on the galvanic series you sent me.
Now, where is the stainless drop elbow deprived of oxygen? Around the threads perhaps. That's where corrosion might occur. Are people in the field seeing this?
So perhaps my question should be, if galvanic corrosion is significant between my stainless drop elbow and my brass nipple, which will corrode? If it's the brass nipple, it's no big deal. I can just replace it. If it's the stainless drop elbow, that's a bigger problem because it will be behind drywall, tile etc.
|
Post Reply
|
Author:
packy (MA)
don't forget, we are operating under a whole new set of rules..
NO LEAD LAWS...
brass used in potable water can not contain any lead.
the chemical make up of lead free brass is different.
whether it is better or worse ?????
|
Post Reply
|
Author:
KCRoto (MO)
metals lower on the chart are saved, higher are sacrificed. Plumbing brass is red brass in fixtures and faucets, cartridge brass in applications like pex fittings. red brass is brownish, cartridge is yellow. Referencing the chart, the relative danger of galvanic corrosion if all other factors is negated is affected solely by the particular alloy of stainless. I can't remember which page I saw it on now as I was looking earlier, but I thought I saw 410 stainless as the type used in most plumbing applications, but like I said, I am not sure. If that is the case, the stainless would be destroyed first. The other factors in play are the relative areas of contact, the presence of an electrolyte, and as you mentioned, the film buildup that can protect the anode (stainless). If you are threading the two together and have sufficient tape/dope in the joint, it limits both the contact and the amount of water between the surfaces, reducing the chance of galvanic corrosion even further.
|
Post Reply
|
Author:
hj (AZ)
quote; brass used in potable water can not contain any lead.
Brass drop ear elbows, since they are not in the potable water flow can be "normal" brass, see the J G Guess product catalog which has that same three hole elbow in "brass not for potable water use".
|
Post Reply
|
Author:
nicholas123 (FL)
That is a good point, Packy. We are in a new era. Modern brass may behave different from older brass with more lead. In fact, if I was able to find a study about galvanic corrosion between stainless steel and brass, it may not apply sufficiently to the brass on the market today.
I started to wonder why lead was in brass to begin with and found this interesting article...
[www.safeplumbing.org]
The stuff they put in modern brass to make up for the missing lead may move it along the galvanic series.
|
Post Reply
|
Author:
KCRoto (MO)
I think I see next year's science project for Sum's son.
|
Post Reply
|
Author:
nicholas123 (FL)
KC, the tape/dope may inhibit corrosion by acting like a resistor to electron flow, but I am not sure it will make a big difference. I say this because tape/dope is applied on the sacrificial anode on a water heater and enough current still travels through the anode to protect the steel water tank. Also, copper plumbing systems are still conductive enough with tape/dope to be used as a home's electrical grounding system.
It's complicated.
As you mentioned, an electrolyte like water is needed. Unfortunately, my water is hard, with a bunch of ions, so it is more conductive and could lead to more corrosion.
All this is just stuff I have read, and using a little logic. I was hoping someone might have first-hand knowledge of stainless on brass galvanic corrosion. But I realize every situation is probably unique.
|
Post Reply
|
Author:
KCRoto (MO)
If the possibility of corrosion worries you that much, use non-metallic piping and spend the extra pennies on brass drop ears so that your shower arm, valves, etc. are all the same material. It isn't money saved if it doesn't last. In a world where time is money, you have already spent your potential savings in fretting about the potential for corrosion.
|
Post Reply
|
Author:
hj (AZ)
Tape and pipe dope, so NOT cover the threads once the joint is made. Their purpose is to fill the voids caused by inaccuracies in the threading and tapping processes.
|
Post Reply
|
Author:
nicholas123 (FL)
Yes, I would enjoy this project more if I didn't worry so much about the money and just make a decision.
With plumbing there seems to be so many options, and when you are a perfectionist it is hard to make a decision.
|
Post Reply
|
Author:
bernabeu (SC)
use a 6" stainless steel nipple for the shower 'arm'
if you need some 'angle' attach a stainless steel 'street 45'
==============================================
"Measure Twice & Cut Once" - Retired U.A. Local 1 & 638
Edited 1 times.
|
Post Reply
|
Author:
packy (MA)
the drop eared elbow for a shower must be lead free as it is considered part of the potable water system..
just like the brass nipple for a urinal flushometer must be lead free. unless the brass nipple is supplied by the manufacturer with the flushometer.
shut off for toilet and water heater relief valve must also be lead free.
2 paragraphs(8 & 9) from this article
[digital.bnpmedia.com]
"The same restriction would be true for drop ear elbows. Most of us thought that leaded drop ear elbows could be used for connecting shower heads or tub fillers. However, this also is prohibited.
The EPA’s concern is that a contractor may confuse the fittings and use a leaded one on a drinking water supply line. There is a lot of validity to this concern."
|
Post Reply
|
Please note:
- Inappropriate messages or blatant advertising will be deleted. We cannot be held responsible for bad or inadequate advice.
- Plbg.com has no control over external content that may be linked to from messages posted here. Please follow external links with caution.
- Plbg.com is strictly for the exchange of plumbing related advice and NOT to ask about pricing/costs, nor where to find a product (try Google), nor how to operate or promote a business, nor for ethics (law) and the like questions.
- Plbg.com is also not a place to ask radiant heating (try HeatingHelp.com), electrical or even general construction type questions. We are exclusively for plumbing questions.
Search for plumbing parts on our sponsor's site:
Special thanks to our sponsor:
|