Quality of Brass in Old vs. New Screws

Yes many things get harder as they age, copper, brass, wood....

getting up in the morning.....

but seriously, metal does not just get harder just laying around doing nothing, but, they may work harden from usage, (some people call it crystalize, but that the wrong terminology).

Metallurgy is not my strong suit, but I never thought about the environment. As far as Precipitation hardening this would come into account with changes in solid solubility with temperature.

Stand corrected.

sorry to disagree,

Brass is an alloy that is made with cupper (copper) and merely zinc. Second of this goes through a mere precipitation cycle.

Why (alu) cast blocks of engines use(d) to be in all weather, sometimes for years?

Okay maybe it wasn't beryllium that is or was a more common impurity that came from processing one of the ores.

I too am not a metallurgist but I do know they put an effort into trying to separate very old brass components form the newer stuff and someone pays good money for it for some reason.

Nice chart. GA. I vote that the new brass screws are from China and they have too much lead content. We went through that issue with brass fittings used in the water industry. NSF actually tested many brass fittings and recalled many pumps with brass ends. It cost the pump industry big time. The lead was leached out of the fitting and into the water supply. Private wells were particularly affected by lead content. I am not sure if screws with high lead content would be less hard but that is my guess.

Thanks for the brass chart; I copied it. Thank your wife too.

Yeah I think they call it precipitation hardening, anybody who has worked with copper tubing knows that when in new shiny condition, it's extremely pliable...but left laying around it gets stiffer....trying to bend old 7/8" copper tubing on a changeout will make a believer out of any skeptic...

I'm not sure about that. Even today you can buy different grades of brass screws, and I'm not sure the the brass colored stuff you get at Home Depot, would even be considered true brass.

http://everestmfgco.com/Brass_Screws_Fasteners.htm

I'm thinking that people rarely order the high grade brass, today, and that maybe all of the old brass would be considered high grade.

My Uncle used to talk about red brass and yellow brass. Red brass was the stronger alloy, yellow was cheaper and not as strong. Yellow brass was slightly less weather/water resistant than red. Most of what we see today (H Depot & the like) is yellow brass.

I'd say that the quest to save money (or, rather maximize profits) probably accounts for the weakening of modern day "brass" hardware.

There's "brass" and then there's brass "alloy" hardware that mostly has only the color in common.

Maybe they are just trying to stay in business. It is hard competing with the 3rd world and now they ( 3rd world ) are competing against themselves. I usually do not pay for quality unless I must.

It could be that 80 to 90 years ago we didn't have this disposable culture. That the hardware was alloyed to last.

Today we have these big stores on every corner that we can run out to to get replacements.

80 - 90 years ago I doubt it. Most likely replacements came mail order and took weeks to get. Don't think many manufactures would do a very good business if their hardware failed like what we have today at these big hardware stores. Their purchasing agent is most likely one step up from the person that checks you out. And like the person that check you out it's all about price. Ever have a conversation with anyone of their so called associates. Have little knowledge of the product. It's questionable if you can find one that even knows where hardware is in the store.

Different alloys to make more profit save money. Zinc is a lot cheaper.

My buddy that has the large scrap yard has commented many times that the old brass is of a different grade and metallurgical formulation than most of the modern brass. If I am recalling things right much of the old brass has more beryllium in it compared to today's brass.

I think it had to do with the base mineral stock they used back then being less refined and having more trace element impurities in them that were actually beneficial to the final products characteristics.

Beryllium is a poisonous metal and needs careful work procedures to prevent long term poisoning and serious health problems....

Maybe thats why it is not seen as often today.....

I found a reasonable explanation here:-

http://en.wikipedia.org/wiki/Beryllium#Precautions

Containing this:-

Approximately 35 micrograms of beryllium is found in the human body, but this amount is not considered harmful.[82] Beryllium is chemically similar to magnesium and therefore can displace it from enzymes, which causes them to malfunction.[82] Chronic berylliosis is a pulmonary and systemic granulomatous disease caused by inhalation of dust or fumes contaminated with beryllium;
either large amounts over a short time or small amounts over a long time can lead to this ailment. Symptoms of the disease can take up to five years to develop; about a third of patients with it die and the survivors are left disabled.

I'm not sure Beryllium is or was the correct element of compound that he was talking about relating to old brass.

As I said he does have some people who ask specifically for old brass regardless of what it was used for and they pay above and beyond normal clean sorted brass market value for it.

You mentioned it first, I only said it was dangerous!! It wasn't in the table if I remember correctly...

One possibility, Doors and drawers was heavier back then, then they are today, so was the hardware used.

May have to go with the premium hardware.

More than one factor may be coming into play.

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Historical brass used in musical instruments is known to age harden. It is a precipitate hardening process related to impurities in historical brass.

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The difference in strength might be more influenced by factors other than the alloy, like difference in the shape, and the way the manufacturer made the screws.