Select material for hot water fitting

huleo · Nov 14, 2018

We have an internal (in our own organization) need for some special water fittings. Fittings will see no more than 200F water temp, all potable water, and in all ways a very simple part. Aluminum would probably work but we have threads to make which is pushing us more towards brass. However, we have not run brass in a long time and about fell over to see the low volume pricing for it!!

I am open to ideas!!! We have thousands of these little guys to make so we need something that machines easy and is cheap. I think I am more or less having sticker shock with brass unless there is a grade we need to look at that is cheaper?

We could probably almost do it in a high temp plastic but I am a bit leery with that because the one factor here is it cannot fail. I realize in plumbing, PEX and such is used without issue so maybe we are being over cautious.

JCByrd24 · Nov 15, 2018

What material is the fitting connected to, what is the environment, and what is the pressure? Aluminum is not often used in residential plumbing likely due to corrosion concerns, but also potential connection to dissimilar metals. Even stainless is uncommon, but likely due to cost in mass production.

Guest · Nov 15, 2018

Look at the cost of bronze and brass will look cheap. All joking aside have you looked at making them from pipe or tubing instead of solid?

atex57 · Nov 15, 2018

Remember, if you have thousands to do you will have a lot of valuable chips. That may offset a lot of the material cost if done in brass.

Ed.

huleo · Nov 15, 2018

Pressure would not exceed 100psi and would be hooking to lines or hoses that have a standard hose connection so that is typically brass or plated steel.

So.... If I wanted to look more at brass, where do I shop? Please don't send me to one of these onlinemetals retailers that charges 15x as much. No one here runs brass that could spot me a good vendor for it?

I guess brass is better in that there should be scrap value. We commonly run high tech plastics and steels and always irritated when I find out our scrap value is next to nothing. Hell, we could not find one place to even take our plastic.

G00 Proto · Nov 15, 2018

If you are already hooking it up to brass or plated brass, you are kind of stuck using brass (galvanic corrosion). Brass prices are definitely high...

It has been a couple of years since I bought brass in volume, but I used to buy from Alaskan Copper and Brass in Seattle.

charlie gary · Nov 15, 2018

How about CPVC?

Wlodek · Nov 15, 2018

One must not use dissimilar metals in water - especially hot water - system. Brass, bronze, copper are compatible, aluminum certainty not. Stainless could be used too, though I only have experience with 316 that is probably more expensive than brass.

MattiJ · Nov 15, 2018

Wlodek said:
Stainless could be used too, though I only have experience with 316 that is probably more expensive than brass.

Judging by scrap prices stainless should be lot cheaper. Brass scrap something like 3usd/kg vs stainless scrap 0.7usd/kg

huleo · Nov 15, 2018

Well I think we have determined that unless Aluminum could be surface treated to resist any corrosion concerns, that will have to be out.

As well, brass and stainless are out. Brass is far too expensive and stainless is both too expensive and would take too much time to process it for what the part does.

basically we need to be in the material costs for the part at somewhere around a buck. We are having to examine plastics I guess.
It is not ideal but things have to stay on budget. It really sort of could be done as an injection mold part but we don't have a machine and have not designed a mold to date so that would be a hurdle. Maybe a good one to learn from though if anyone has any thoughts.

I looked at some pricing on CPVC and it seems to be right at double the price of PVC in rods, and Nylon was around the price of PVC. Problem is trying to find good data for these materials to compare, not just the melting point.

Wlodek · Nov 15, 2018

I would be hesitant to use plastic for long term application with hot water especially if the water is chlorinated. Chlorine makes most plastics brittle and even hot water by itself can create dimensional changes in the fitting causing leaks. CPVC is used for domestic hot water but almost all threaded CPVC fittings I have seen have brass insets for the treads. With a metal male thread threaded inside all plastic CPVC fitting there is increased danger of leaks developing after some time as the fitting gets loose. In domestic plumbing most, if not all, fittings and pipes are cemented.

garyhlucas · Nov 15, 2018

Who is doing the assembly? We build waste treatment plants using PVC and contractors broke so many threaded fittings that we now install sacrificial bushings at every thread location, so we can replace the broken bushing instead of the whole assembly.

72bwhite · Nov 15, 2018

I want gas for a buck a gallon too

rcoope · Nov 15, 2018

What about HDPE? It's pretty inert and more pH resistant than Acetal and decently strong. I'd like to know more about the application as the design of the part has a potential role to play.

LKeithR · Nov 15, 2018

I think there's a flaw in your process somewhere. Brass is clearly the "right" material for the job and, especially if you've
got "thousands" to do, you should have built your budget around that material. Using an inferior material to save money
seldom works out in the long run--go cheap now and there's a very good chance that it will come back to bite you in the
future...

Screwmachine · Nov 16, 2018

Seems silly to use an inferior material in a situation where your part "can't fail". Maybe you'll make budget this go round and then get a nice new budget down the road to remake and reinstall these things.

adama · Nov 16, 2018

Is there a existing fitting you can buy in and simply modify? I did hundreds of adaptations on a 3/4 bsp brass bit for a local boiler company a few years back, they could bulk buy the fittings and pay me to modify them for less than we could buy the solid brass rod any were, brass tube was even more costly. I have a meter of 1 1/4" solid brass here and its damn near doubled in price in the last few years.

I would add serious caution to the plastic parts idea, people are anamals and you will be left fixing the damage and replacment, does not need many warrentie claims to soon make the brass parts seam free. Theres good reason solid brass is the long time proven hot water industry std material for these kinda bits.

SeymourDumore · Nov 16, 2018

Screwmachine said:
Seems silly to use an inferior material in a situation where your part "can't fail".

Can't fail but it must be cheap.....
It ain't silly, rather stupid.

And to boot, stainless is too much time to process..... :scratchchin:

Guest · Nov 16, 2018

Hard for me to recommend anyone as any large quantity of brass I picked it up myself. Some places aren't so kind about arranging economic shipping, they want to UPS it to you and mark up their discount to UPS list and then some. I guess you could call Fry Steel in the Los Angeles area or the closest Industrial Metal Supply, I bought brass from them when on the left coast, but I always picked it up.

Mtndew · Nov 16, 2018

Since you have thousands to do, use brass. Just take care to keep all of the chips and sell them for scrap.

Select material for hot water fitting

Hot Rolled

Aluminum

Guest

Guest

Stainless

Hot Rolled

Hot Rolled

Stainless

Aluminum

Titanium

Hot Rolled

Aluminum

Stainless

Titanium

Stainless

Stainless

Titanium

Diamond

Diamond

Guest

Guest

Diamond

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